,transcrib]'s ,notes3 ,! spell+1 hyph5ation1 punctuation & acc5tuation are z ! orig9al1 except = app>5t typographical errors :i* h be5 correct$4 ,italic text is d5ot$ ?us4 ,bold text is d5ot$ ?us4 ,see fur!r notes at ! end ( ! book4 ,illu/ration3 ,,g5]al ,,view ,,( ,,filt]s ,,at ,,hamburg4 ,frontispiece4 ,,! ,,filtration ,,( ,,public ,,wat]-,,supplies4 ,,by ,,all5 ,,haz51 ,,memb] ,,( ,,! ,,am]ican ,,society ,,( ,,civil ,,eng9e]s1 ,,! ,,bo/on ,,society ,,( ,,civil ,,eng9e]s1 ,,! ,,am]ican ,,wat]-,,works ,,association1 ,,! ,,new ,,engl& ,,wat]-,,works ,,association1 ,,! ,,am]ican ,,*emical ,,society1 ,,! ,,am]ican ,,public ,,heal? ,,association1 ,,etc4 ,,?ird ,,edition1 ,,revis$ ,,& ,,enl>g$4 ,,second ,,?\s&4 ,,new ,,york3 ,,john ,,wiley ,,sons4 ,,london3 ,,*apman ,,hall1 ,,limit$4 #aije4 ,copyright1 #aijj1 ,,by ,,all5 ,,haz54 ,,rob]t ,,drummond1 ,,electrotyp] ,,& ,,pr9t]1 ,,new ,,york4 ,,preface ,,to ,,fir/ ,,edition4 ,! subject ( wat]-filtration is comm5c+ to receive a great deal ( att5tion 9 ! ,unit$ ,/ates4 ,! m d5sely populat$ ,european c\ntries 7 =c$ to adopt filtration _m ye>s ago1 to prev5t ! evils aris+ f ! unavoidable contam9ations ( ! riv]s & lakes :i* 7 ! only available s\rces = _! public wat]-supplies2 & x has be5 f\nd to answ] its purpose s well t at ! pres5t "t cities 9 ,europe ne>ly if n q equal 9 population to all ! cities ( ! ,unit$ ,/ates are suppli$ ) filt]$ wat]4 ,_m ye>s ago1 :5 ! :ole subject ( wat]-supply 0 /ill comp>atively new 9 ?is c\ntry1 filtration 0 consid]$ z a means = r5d]+ ! wat]s ( our riv]s suitable = ! purpose ( dome/ic wat]-supply4 ,/4 ,l\is inve/igat$ ?is subject 9 #ahff1 & ! eng9e] ( ! ,/4 ,l\is ,wat] ,bo>d1 ! late ,mr4 ,j4 ,p4 ,kirkwood1 made an inve/igation & report ^u ,european me?ods ( filtration :i* 0 publi%$ 9 #ahfi1 & 0 su* a model ( full & accurate /atem5t comb9$ ) cle>ly-drawn conclusions t1 up to ! pres5t "t1 x has rema9$ ! only treatise ^u ! subject 9 ,engli%1 not)/&+ ! great advances :i* h be5 made1 p>ticul>ly 9 ! la/ t5 ye>s1 ) ! aid ( k ( ! bact]ia & ! g]ms ( c]ta9 diseases 9 wat]4 ,un=tunately ! int]e/ 9 ! subject 0 n ma9ta9$ 9 ,am]ica1 b 0 all[$ to lag = _m ye>s2 x 0 *eap] to use ! wat] 9 its raw /ate ?an x 0 to purify x2 ! p became indiff]5t to ! dang] ( su* use1 & ! disa/r\s epidemics ( *ol]a & typhoid fev]1 z well z ( m9or diseases1 :i* s (t5 result$ f ! use ( pollut$ wat]1 7 attribut$ to o!r causes4 ,) increas+ /udy & diffusion ( k ! relations ( wat] & disease are becom+ bett] kn[n1 & ! pres5t /ate ( ?+s w n be all[$ to cont9ue2 inde$ at pres5t !re is inquiry at e h& z to ! me?ods ( improv+ wat]s4 ,! "o un=tunate feature is ! "q ( co/4 ,n t ! co/ ( filtration is excessive or beyond ! means ( ,am]ican communities2 9 po9t ( fact1 exactly ! rev]se is ! case2 b we h be5 s long accu/om$ to obta9 dr9k+-wat] )\t exp5se o!r ?an pump+ t any co/ t5d+ to improv$ quality seems excessive1 ?us af=d+ a *ance = ! in/allation ( inf]ior filt]s1 :i* by fail+ to produce ! promis$ results t5d to br+ ! :ole process into disrepute1 s9ce few p c di/+ui% betwe5 an adequate filtration & a poor sub/itute = x4 ,x is und\bt$ly true t improvem5ts are made1 & w cont9ue to be made1 9 processes ( filtration2 s x w (t5 be possible to r$uce ! exp5se ( ! process )\t decreas+ ! effici5cy1 b great c>e mu/ be ex]cis$ 9 su* cases to ma9ta9 ! conditions really ess5tial to success4 ,9 ! pres5t volume ,i h endeavor$ to expla9 briefly ! nature ( filtration & ! conditions :i*1 9 half a c5tury ( ,european practice1 h be5 f\nd ess5tial = successful practice1 ) a view ( /imulat+ int]e/ 9 ! subject1 & ( prev5t+ ! un=tunate & disappo9t+ results :i* s easily result f ! con/ruction ( inf]ior filt]s4 ,! economies :i* may possibly result by ! use ( an inf]ior filtration are comp>atively small1 & x is believ$ t 9 ^? ,am]ican cities :]e filtration is necess>y or desirable x w be f\nd be/ 9 e case to furni% filt]s ( ! be/ con/ruction1 fully able to d :at is requir$ ( !m ) ease & c]ta9ty4 ,,preface ,,to ,,?ird ,,edition4 ,!re h be5 sev]al di/9ct epo*s 9 ! developm5t ( wat] purification 9 ! ,unit$ ,/ates4 ,! fir/ may be said to date f ,kirkwood's report on ! 8,filtration ( ,riv] ,wat]s10 & ! second f ! inauguration ( ! ,lawr5ce ,exp]im5t ,/ation by ! ,massa*usetts ,/ate ,bo>d ( ,heal?1 & ! con/ruction ( ! ,lawr5ce city filt]1 ) ! demon/ration ( ! wond]ful biological action ( filt]s ^u highly pollut$ wat]s4 ,! ?ird epo* is m>k$ by ! exp]im5ts at ,l\isville1 ,pittsburg & ,c9c9nati1 :i* h greatly increas$ our k ( ! treatm5t ( wat]s conta9+ enorm\s quantities ( susp5d$ matt]1 & h r$uc$ to some?+ l ord] ! previ\sly exi/+ confus$ mass ( data reg>d+ coagulation & rapid filtration4 ,! fir/ edition ( ?is book repres5t$ ! e>li] epo*s be=e ! op5+ ( ! ?ird4 ,9 ! five ye>s s9ce x 0 writt51 progress 9 ! art ( wat] purification has be5 rapid & sub/antial4 ,no apology is ne$$ = ! v complete revision requir$ to treat ^! newly inve/igat$ subjects z fully z 7 o!r matt]s 9 ! e>li] editions4 ,9 ! pres5t edition ! fir/ sev5 *apt]s rema9 ) b few additions4 ,exp]i5ce has /r5g!n$ ! propositions conta9$ 9 !m4 ,new data might h be5 add$1 b 9 few cases w\ld ! conclusions h be5 alt]$4 ,! rema9+ *apt]s ( ! book h be5 entirely rewritt5 & enl>g$ to repres5t ! add$ in=mation n[ available1 s t ! pres5t edition is ne>ly twice z l>ge z ! e>li] ones4 ,9 ! app5dices1 also1 mu* matt] has be5 add$ relat+ to works 9 op]ation1 p>ticul>ly to ^? 9 ,am]ica4 ,,new ,,york ,janu>y1 #aijj4 ,,cont5ts4 ,,page ,*apt] ,i4 ,,introduction4 #a ,,ii4 ,,cont9u\s ,,filt]s ,,& ,,_! ,,con/ruction #e ,s$im5tation-bas9s #h ,size ( ,filt]-b$s #aj ,=m ( ,filt]-b$s #aa ,cov]s = ,filt]s #ab ,,iii4 ,,filt]+-,,mat]ials #bj ,s& #bj ,s&s ,us$ 9 ,european ,filt]s #bd ,effect ( ,size ( ,gra9 ,^u ,effici5cy ( ,filtration #cj ,effect ( ,gra9 ,size ,^u ,frequ5cy ( ,scrap+ #cb ,selection ( ,s& #cc ,?ickness ( ! ,s& ,lay] #cd ,und]dra9+ #ce ,gravel ,lay]s #ce ,und]dra9s #ci ,dep? ( ,wat] on ,filt]s #de ,,iv4 ,,rate ,,( ,,filtration ,,& ,,loss ,,( ,,head #dg ,effect ( ,rate ,^u ,co/ ( ,filtration #dh ,effect ( ,rate ,^u ,effici5cy ( ,filtration #ej ,! ,loss ( ,head #eb ,regulation ( ! ,rate & ,loss ( ,head 9 ! ,old] ,filt]s #eb ,app>atus ,= ,regulat+ ! ,rate & ,loss ( ,head #ee ,app>atus ,= ,regulat+ ! ,rate ,directly #eg ,app>atus ,= ,regulat+ ! ,height ( ,wat] ,^u ,filt]s #ei ,limit to ! ,loss ( ,head #fj ,v4 ,,clean+ ,,filt]s #fh ,frequ5cy ( ,scrap+ #gb ,quantity ( ,s& to ,be ,remov$ #gd ,wa/+ ! ,efflu5ts ,aft] ,scrap+ #gd ,s&-wa%+ #gf ,,vi4 ,,!ory ,,& ,,effici5cy ,,( ,,filtration #hc ,bact]ial ,exam9ation ( ,wat]s #ic ,,vii4 ,,int]mitt5t ,,filtration #ig ,! ,lawr5ce ,filt] #ajj ,*emnitz ,wat]-,works #ajg ,application ( ,int]mitt5t ,filtration #aaa ,,viii4 ,,turbidity ,,& ,,color1 ,,& ,,! ,,effect ,,( ,,mud ,,^u ,,s& ,,filt]s #aac ,! ,measurem5t ( ,color #aad ,am\nt ( ,color 9 ,am]ican ,wat]s #aae ,removal ( ,color #aag ,measurem5t ( ,turbidity #aag ,relation ( ,plat9um-wire ,turbidities to ,susp5d$ ,matt]s #abb ,s\rce ( ,turbidity #abc ,! ,am\nts ( ,susp5d$ ,matt]s 9 ,wat] #abi ,prelim9>y ,processes to remove ,mud #acc ,effect ( ,mud ^u ,s& ,filt]s #acg ,effect ( ,turbidity ,^u ! ,l5g? ( ,p]iod #acg ,p[] ( ,s& ,filt]s to ,produce ,cle> ,efflu5ts f ,muddy ,wat] #aci ,effect ( ,mud ,^u ,bact]ial ,effici5cy ( ,filt]s #ada ,limits to ! ,use ( ,subsid5ce = ! ,prelim9>y ,treatm5t ( ,muddy ,wat]s #adb ,,ix4 ,,coagulation ,,( ,,wat]s #add ,sub/ances us$ = ,coagulation #ade ,coagulants ,:i* ,h ,be5 ,us$ #aej ,am\nt ( ,coagulant requir$ to remove ,turbidity #aej ,am\nt ( ,coagulant requir$ to remove ,color #aec ,successive ,applications ( ,coagulant #aed ,! ,am\nt ( ,coagulant :i* ,v>i\s ,wat]s w receive #aee ,x4 ,,me*anical ,,filt]s #aei ,provid5ce ,exp]im5ts #aei ,l\isville,exp]im5ts #afa ,lora9 ,te/s #afa ,pittsburg ,exp]im5ts #afb ,wa/+ ,efflu5t ,aft] ,wa%+ ,filt]s #afc ,influ5ce ( ,am\nt ( ,sulphate ( ,alum9a on ,bact]ial ,effici5cy ( ,me*anical ,filt]s #afe ,influ5ce ( ,degree ( ,turbidity ^u ,bact]ial ,effici5cy ( ,me*anical ,filt]s #afg ,av]age ,results ,obta9$ ) ,v>i\s ,quantities ( ,sulphate ( ,alum9a #aga ,types ( ,me*anical ,filt]s #agb ,effici5cy ( ,me*anical ,filt]s #agi ,pressure ,filt]s #ahj ,,xi4 ,,o!r ,,me?ods ,,( ,,filtration #aha ,worms ,tile ,sy/em #aha ,! ,use ( ,asbe/os #aha ,filt]s ,us+ ,high ,rates ( ,filtration ,)\t ,coagulants #ahb ,h\sehold ,filt]s #ahc ,,xii4 ,,removal ,,( ,,iron ,,f ,,gr\nd-,,wat]s #ahf ,am\nt ( ,iron ,requir$ to ,r5d] ,wat] ,objectionable #ahf ,cause ( ,iron 9 ,gr\nd-wat]s #ahg ,treatm5t ( ,iron-conta9+ ,wat]s #ahi ,iron-removal ,plants 9 ,op]ation #aib ,,xiii4 ,,treatm5t ,,( ,,wat]s #aig ,co/ ( ,filtration #bjj ,:at ,wat]s ,require ,filtration #bjg ,,xiv4 ,,wat]-,,supply ,,& ,,disease--,,conclusions #baj ,app5dix ,i4 ,,rules ,,( ,,! ,,g]man ,,gov]nm5t ,,9 ,,reg>d ,,to ,,! ,,filtration ,,( ,,surface-,,wat]s ,,us$ ,,= ,,public ,,wat]-,,supplies #bba ,,ii4 ,,extracts ,,f 8,,b]i*t ,,des ,,m$ic9al-,,inspectorats ,,des ,,hamburgis*5 ,,/aates ,f,r ,,das ,,jahr #ahib0 #bbf ,,iii4 ,,me?ods ,,( ,,s&-,,analysis #bcc ,,iv4 ,,filt] ,,/ati/ics #bda ,/ati/ics ( ,op]ation ( ,s& ,filt]s #bda ,p>tial ,li/ ( ,cities ,us+ ,s& ,filt]s #bdd ,li/ ( ,cities & ,t[ns ,us+ ,me*anical ,filt]s #bdg ,notes ,reg>d+ ,s& ,filt]s 9 ! ,unit$ ,/ates #bea ,capacity ( ,filt]s #bed ,v4 ,,london',s ,,wat]-,,supply #bee ,,vi4 ,,! ,,b]l9 ,,wat]-,,works #bfa ,,vii4 ,,altona ,,wat]-,,works #bfe ,,viii4 ,,hamburg ,,wat]-,,works #bfi ,,ix4 ,,notes ,,on ,,"s ,,o!r ,,european ,,wat]-,,supplies #bgb ,! ,use ( ,unfilt]$ ,surface-wat]s4 #bge ,! ,use ( ,gr\nd-wat]4 #bgf ,x4 ,,lit]ature ,,( ,,filtration #bgg ,,xi4 ,,! ,,albany ,,wat]-,,filtration ,,plant #bhh ,description ( ,plant4 #bhi ,capacity ( ,plant & ,means ( ,regulation4 #cjh ,results ( ,op]ation4 #cad ,co/ ( ,con/ruction4 #cad ,,index #cag ,,units ,,employ$4 ,! units us$ 9 ?is "w are uni=mly ^? 9 common use 9 ,am]ica1 ) ! s+le exception ( data 9 reg>d to s&-gra9 sizes1 :i* are giv5 9 millimet]s4 ,! ,am]ican units 7 n select$ because ! au?or pref]s !m or consid]s !m p>ticul>ly well suit$ to filtration1 b because he fe>$ t ! use ( ! m conv5i5t metric units 9 :i* ! v compreh5sive records ( ,cont95tal filt] plants are kept w\ld add to ! difficulty ( a cle> compreh5sion ( ! subject by ^? n famili> ) ^? units1 & s 9 a measure defeat ! object ( ! book4 ,,table ,,( ,,equival5ts4 ,unit4 ,metric ,equival5t4 ,reciprocal4 ,foot #j4cjdh met] #c4bhjh ,mile #afji4cd met]s #j4jjjfbad ,acre #djdg squ>e met]s #j4jjjbdga ,gallon#a #c4ghe lit]s #j4bfdag #a million gallons #cghe cubic met]s #j4jjjbfdag ,cubic y>d #j4gfde cubic met]s #a4cjh #a million gallons p] met] 9 dep? acre daily #j4iced ( wat] daily #a4jgj ,,ackn[l$gm5t4 ,i wi% to ackn[l$ge my deep obligation to ! l>ge numb] ( ,european eng9e]s1 directors1 & sup]9t5d5ts ( wat]-works1 & to ! heal? (fic]s1 *emi/s1 bact]iologi/s1 & o!r (ficials :o h k9dly aid$ me 9 /udy+ ! filtration-works 9 _! respective cities1 & :o h repeat$ly furni%$ me ) valuable in=mation1 /ati/ics1 plans1 & reports4 ,to m5tion all ( !m w\ld be impossible1 b ,i wi% p>ticul>ly to m5tion ,major-,g5]al ,scott1 ,wat]-exam9] ( ,london2 ,mr4 ,mans]gh1 ,memb] ( ! ,royal ,commission on ! ,wat]-supply ( ! ,metropolis2 ,mr4 ,bryan1 ,eng9e] ( ! ,ea/ ,london ,wat] ,company2 & ,mr4 ,wilson1 ,manag] ( ! ,middlesbor\gh ,wat]-works1 :o h favor$ me ) mu* valuable in=mation4 ,9 ,holl& & ,belgium ,i am "u special obligations to ,messrs4 ,van ,hasselt & ,kemna1 ,directors ( ! wat] companies at ,am/]dam & ,antw]p respectively2 to ,director ,/ang ( ! ,hague ,wat]-works2 to ,dr4 ,van't ,h(f1 ,sup]9t5d5t ( ! ,rott]dam filt]s2 & to my fri5d ,h4 ,p4 ,n4 ,halb]tsma1 :o1 z consult+ eng9e]1 has built _m ( ! ,dut* wat]-works4 ,9 ,g]many ,i mu/ m5tion ,pr(s4 ,frhl+1 at ,dresd51 & ,flgge1 at ,breslau2 ,&reas ,mey]1 ,city ,eng9e] ( ,hamburg2 & ! ,directors ( wat]-works1 ,be] at ,b]l91 ,dieckmann at ,magdeburg1 ,nau at ,*emnitz1 & ,jockmann at ,liegnitz1 z well z ! ,sup]9t5d5t ,eng9e]s ,s*ro$] at ,hamburg1 ,debusmann at ,breslau1 & ,anklamm & ,piefke at ,b]l91 ! latt] ! di/+ui%$ head ( ! ,/ralau works1 ! fir/ & mo/ widely kn[n ^u ! ,cont95t ( ,europe4 ,i h to ackn[l$ge my obligation to ,city ,eng9e] ,se*n] at ,budape/1 & to ! ,assi/ant ,eng9e] 9 *>ge ( wat]-works1 ,kajl+]2 to ,city ,eng9e] ,pet]s & ,city ,*emi/ ,b]ts*+] at ,zri*2 & to ,assi/ant ,eng9e] ,regn>d ( ! ,compagnie ,gnrale des ,eaux at ,p>is4 ,on ?is side ( ! ,atlantic also ,i am indebt$ to ,hiram ,f4 ,mills1 ,c4,e41 "u ^: direction ,i _h ! privilege ( conduct+ = ne>ly five ye>s ! ,lawr5ce exp]im5ts on filtration2 to ,pr(s4 ,s$gwick & ,dr[n = ! num]\s sugge/ions & fri5dly criticisms1 & to ! latt] = k9dly read+ ! pro( ( ?is volume2 to ,mr4 ,g4 ,w4 ,full] = full in=mation 9 reg>d to ! m rec5t ,lawr5ce results2 to ,mr4 ,h4 ,w4 ,cl>k = ! labori\s exam9ation ( ! l>ge numb] ( samples ( s&s us$ 9 actual filt]s & m5tion$ 9 ?is volume2 & to ,mr4 ,desmond ,fitz,gerald = unpubli%$ in=mation 9 reg>d to ! results ( 8 valuable exp]im5ts on filtration at ! ,*e/nut ,hill ,res]voir1 ,bo/on4 ,,all5 ,,haz54 ,,bo/on1 ,april1 #ahie4 ,,filtration ,,( ,,public ,,wat]-,,supplies4 ,,*apt] ,i4 ,,introduction4 ,! rapid & enorm\s developm5t & ext5sion ( wat]-works 9 e civiliz$ c\ntry dur+ ! pa/ =ty ye>s is a matt] :i* des]ves our mo/ c>eful consid]ation1 z !re is h>dly a subject :i* m directly affects ! heal? & happ9ess ( almo/ e s+le inhabitant ( all cities & l>ge t[ns4 ,consid]+ ! mod]n me?ods ( communication1 & ! free ex*ange ( ideas betwe5 nations1 x is really m>vell\s h[ ea* c\ntry has met its problems ( wat]-supply f its own res\rces1 & (t5 )\t mu* reg>d to ! me?ods :i* _h be5 f\nd mo/ useful else:]e4 ,engl& has secur$ a :ole s]ies ( magnific5t supplies by imp\nd+ ! wat]s ( small /reams 9 res]voirs hold+ en\gh wat] to la/ ?r\gh dry p]iods1 :ile on ,cont95tal ,europe su* supplies are h>dly kn[n4 ,g]many has sp5t millions ^u millions 9 purify+ turbid & pollut$ riv]-wat]s1 :ile ,france & ,au/ria h /riv5 = m\nta9-spr+ wat]s & h built hundr$s ( miles ( co/ly aqu$ucts to secure !m4 ,9 ! ,unit$ ,/ates an abundant supply ( "s liquid has too (t5 be5 ! objective po9t1 & ! ef=ts h be5 mo/ successful1 ! ,am]ican works be+ entirely unrivall$ 9 ! volumes ( _! supplies4 ,i d n wi% to imply t quality has be5 entirely neglect$ 9 our c\ntry1 = _m cities & t[ns h s]i\sly & successfully /udi$ _! problems1 ) ! result t !re are hundr$s ( wat]-supplies 9 ! ,unit$ ,/ates :i* w comp>e favorably ^u any basis ) supplies 9 any "p ( ! _w2 b on ! o!r h& x is equally true t !re are hundr$s ( o!r cities1 includ+ "s among ! l>ge/ 9 ! c\ntry1 :i* supply _! citiz5s ) turbid & unheal?y wat]s :i* _c be reg>d$ z any?+ else ?an a national disgrace & a m5ace to our prosp]ity4 ,"o c travel ?r\gh ,engl&1 ,belgium1 ,holl&1 ,g]many1 & l>ge portions ( o!r ,european c\ntries & dr9k ! wat] at e city visit$ )\t anxiety z to its effect ^u 8 heal?4 ,x has n always be5 s4 ,=m]ly ,european capitals drank wat] no bett] ?an t s (t5 disp5s$ n[ 9 ,am]ica4 ,z rec5tly z #ahib ,g]many's great comm]cial c5tre1 ,hamburg1 hav+ a wat]-supply ess5tially l ^? ( ,philadelphia1 ,pittsburg1 ,c9c9nati1 ,/4 ,l\is1 ,new ,orleans1 & a hundr$ o!r ,am]ican cities1 paid a p5alty 9 "o mon? ( eight ?\s& lives = its c>elessness4 ,! lesson 0 a de> "o1 b x 0 n wa/$4 ,hamburg n[ has a new & :olesome supply1 & o!r ,g]man cities ! qualities ( ^: wat]s 7 op5 to "q h be5 =c$ to take active measures to bett] _! conditions4 ,we also c le>n some?+ f _! exp]i5ce4 ,!re are ?ree pr9cipal me?ods ( secur+ a good wat]-supply = a l>ge city4 ,! fir/ consi/s ( damm+ a /ream f an un9habit$ or b sp>sely inhabit$ wat]%$1 ?us =m+ an imp\nd+ res]voir4 ,?is me?od is ext5sively us$ 9 ,engl& & 9 ! ,unit$ ,/ates4 ,9 ! latt] mo/ ( ! really good & l>ge supplies are s obta9$4 ,x is only applicable to places hav+ suitable wat]%$s )9 a reasonable di/ance1 & !re are l>ge regions :]e1 ow+ to geological & o!r conditions1 x _c be appli$4 ,x is mo/ useful 9 hilly & poor f>m+ c\ntries1 z 9 p>ts ( ,engl& & ,wales1 9 ! ,atlantic ,/ates1 & 9 ,cali=nia4 ,x _c be us$ to any consid]able ext5t 9 level & f]tile c\ntries :i* are sure to be or to become d5sely populat$1 z is ! case ) l>ge p>ts ( ,france & ,g]many & 9 ! ,middle ,/ates4 ,! second me?od is to secure gr\nd-wat]1 t is1 spr+ or well wat]1 :i* by its passage ?r\gh ! gr\nd has become ?or\ghly purifi$ f any impurities :i* x may h conta9$4 ,?is 0 ! e>lie/ & is ! mo/ widely us$ me?od ( secur+ good wat]4 ,x is specially adapt$ to small supplies4 ,"u favorable geological conditions v l>ge supplies h be5 obta9$ 9 ?is mann]4 ,9 ,europe ,p>is1 ,vi5na1 ,budape/1 ,muni*1 ,cologne1 ,leipzig1 ,dresd51 a "p ( ,london1 & v _m small] places are s suppli$4 ,?is me?od is also ext5sively us$ 9 ! ,unit$ ,/ates = small & m$ium-siz$ places1 & des]ves to be mo/ c>efully /udi$1 & us$ :5ev] possible1 b is un=tunately limit$ by geological conditions & _c be us$ except 9 a fraction ( ! cases :]e supplies are requir$4 ,no gr\nd-wat] supplies yet develop$ 9 ! ,unit$ ,/ates are comp>able 9 size to ^? us$ 9 ,europe4 ,! ?ird process ( secur+ a good wat]-supply is by means ( filtration ( surface wat]s :i* w\ld o!rwise be unsuitable = dome/ic purposes4 ,! me?ods ( filtration1 :i* x is ! purpose ( ?is volume to expla91 are beyond ! exp]im5tal /age2 !y are n[ appli$ to ! purification ( ! wat]-supplies ( ,european cities ) an aggregate population ( at lea/ #bj1jjj1jjj p4 ,9 ! ,unit$ ,/ates ! use ( filt]s is mu* less common1 & mo/ ( ! filt]s 9 use are ( comp>atively rec5t in/allation4 ,great int]e/ has be5 %[n 9 ! subject dur+ ! la/ few ye>s1 & ! peculi> "* ( "s ,am]ican wat]s1 :i* diff] widely 9 _! prop]ties f ^? ( _m ,european /reams1 has receiv$ c>eful & exhau/ive consid]ation4 ,9 ,europe filtration has be5 practis$ ) cont9ually improv+ me?ods s9ce #ahbi1 & ! process has /eadily receiv$ wid] & wid] application4 ,x has be5 mo/ se>*+ly inve/igat$ 9 its hygi5ic relations1 & has be5 repeat$ly f\nd to be a mo/ valuable aid 9 r$uc+ mortality4 ,! conditions "u :i* satisfactory results c be obta9$ are n[ tol]ably well kn[n1 s t filt]s c be built 9 ! ,unit$ ,/ates ) ! utmo/ confid5ce t ! result w n be disappo9t+4 ,! co/ ( filtration1 al?\gh consid]able1 is n s great z to put x beyond ! rea* ( ,am]ican cities4 ,x may be r\ghly e/imat$ t ! co/ ( filtration1 ) all necess>y int]e/ & s9k+ funds1 w add #aj p] c5t to ! av]age co/ ( wat] z at pres5t suppli$4 ,x may be confid5tly expect$ t :5 ! facts are bett] und]/ood & realiz$ by ! ,am]ican public1 we %all ab&on ! pres5t fil?y & unheal?y habit ( dr9k+ pollut$ riv] & lake wat]s1 & %all put ! quality z well z ! quantity ( our supplies ^u a level n exce$$ by ^? ( any c\ntry4 ,,*apt] ,,ii4 ,,cont9u\s ,,filt]s ,,& ,,_! ,,con/ruction4 ,filtration ( wat] consi/s 9 pass+ x ?r\gh "s sub/ance :i* reta9s or removes "s ( its impurities4 ,9 its simple/ =m filtration is a /ra9+ process1 & ! results obta9$ dep5d ^u ! f95ess ( ! /ra9]1 & ?is 9 turn is regulat$ by ! "* ( ! wat] & ! uses to :i* x is to be put4 ,?us 9 ! manufacture ( pap] an enorm\s volume ( wat] is requir$ free f p>ticles :i*1 if !y %\ld become imb$d$ 9 ! pap]1 w\ld injure its appe>ance or texture4 ,obvi\sly = ?is purpose ! removal ( ! small] p>ticles sep>ately invisible to ! unaid$ eye1 & ?us n affect+ ! appe>ance ( ! pap]1 & ! removal ( :i* w\ld require ! use ( a f9] filt] at increas$ exp5se1 w\ld be a simple wa/e ( money4 ,:51 h[ev]1 a wat] is to be us$ = a dome/ic wat] supply & transp>5cy is an object1 ! /ill f9] p>ticles :i* w\ld n %[ !mselves 9 pap]1 b :i* are /ill able1 9 bulk1 to r5d] a wat] turbid1 %\ld be z f> z possible remov$1 ?us necessitat+ a f9] filt]2 &1 :5 !re is reason to ?9k t ! wat] conta9s ! g]ms ( disease1 ! filt] mu/ be f9e en\gh to remove ) c]ta9ty ^? organisms s extraord9>ily small t millions ( !m may exi/ 9 a glass ( wat] )\t imp>t+ a visible turbidity4 ,x is n[ some?+ ov] half a c5tury s9ce ! fir/ successful attempts 7 made to filt] public wat]-supplies1 & !re are n[ hundr$s ( cities suppli$ ) cle>1 heal?y1 filt]$ wat]4 7,app5dix ,,iv47 ,:ile ! details ( ! filt]s us$ 9 diff]5t places pres5t consid]able v>iations1 ! g5]al =m is1 9 ,europe at lea/1 ev]y:]e ! same4 ,! mo/ important p>ts ( a filt] are %[n by ! accompany+ sket*1 9 :i* ! dim5sions are mu* exagg]at$4 ,! raw wat] is tak5 f ! riv] into a settl+-bas91 :]e ! heavie/ mud is all[$ to settle4 ,9 ! case ( lake & pond wat]s ! settl+-tank is disp5s$ )1 b x is ess5tial = turbid riv]-wat]1 z o!rwise ! mud clogs ! filt] too rapidly4 ,! p>tially cl>ifi$ wat] !n passes to ! filt]1 :i* consi/s ( a horizontal lay] ( r f9e s& support$ by gravel & und]dra9$1 ! :ole be+ enclos$ 9 a suitable bas9 or tank4 ,! wat] 9 pass+ ?r\gh ! s& leaves beh9d ^u ! s& gra9s ! extremely small p>ticles :i* 7 too f9e to settle out 9 ! settl+-bas91 & is q cle> z x goes f ! gravel to ! dra9s & ! pumps1 :i* =w>d x to ! res]voir or city4 ,illu/ration3 ,,fig4 #a4--,,sket* ,,%[+ ,,g5]al ,,arrangem5t ,,( ,,filt] ,,plants4 ,! passages betwe5 ! gra9s ( s& ?r\gh :i* ! wat] mu/ pass are extremely small4 ,if ! s& gra9s 7 sph]ical & #a_/ej ( an in* 9 diamet]1 ! op5+s w\ld only all[ ! passage ( o!r sph]es #a_/cbj ( an in* 9 diamet]1 & ) actual irregul> s&s mu* f9] p>ticles are held back4 ,z a result ! co>s] matt]s 9 ! wat] are reta9$ on ! surface ( ! s&1 :]e !y quickly =m a lay] ( s$im5t1 :i* itself becomes a filt] mu* f9] ?an ! s& alone1 & :i* is capable ( hold+ back "u suitable conditions ev5 ! bact]ia ( ! pass+ wat]4 ,! wat] :i* passes be=e ?is takes place may be less p]fectly filt]$1 b ev5 !n1 ! filt] may be s op]at$ t ne>ly all ( ! bact]ia w be deposit$ 9 ! s& & n all[$ to pass ?r\gh into ! efflu5t4 ,z ! s$im5t lay] increases 9 ?ickness ) cont9u$ filtration1 increas$ pressure is requir$ to drive ! desir$ volume ( wat] ?r\gh its pores1 :i* are ev] becom+ small] & r$uc$ 9 numb]4 ,:5 ! requir$ quantity ( wat] w no long] pass ) ! maximum pressure all[$1 x is necess>y to remove1 by scrap+1 ! s$im5t lay]1 :i* %\ld n be m ?an an in* deep4 ,?is lay] conta9s mo/ ( ! s$im5t1 & ! rema9+ s& w !n act almo/ z new s& w\ld d4 ,! s& remov$ may be wa%$ = use aga91 & ev5tually replac$ :5 ! s& lay] becomes too ?9 by repeat$ scrap+s4 ,^! op]ations require t ! filt] %all be tempor>ily out ( use1 & z wat] mu/ 9 g5]al be suppli$ )\t int]mission1 a numb] ( filt]s are built toge!r1 s t any ( !m c be %ut out )\t int]f]+ ) ! action ( ! o!rs4 ,! arrangem5t ( filt]s 9 relation to ! pumps v>ies ) local conditions4 ,) gravity supplies ! filt]s are usually locat$ bel[ ! /orage res]voir1 &1 prop]ly plac$1 involve only a few feet loss ( head4 ,9 ! case ( tidal riv]s1 z at ,antw]p & ,rott]dam1 ! quality ( ! raw wat] v>ies ) ! tide1 & !re is a great advantage 9 hav+ ! settl+-bas9s l[ en\gh s t a :ole day's supply c be rapidly let 9 :5 ! wat] is at its be/1 )\t pump+4 ,at ,antw]p ! filt]s are high]1 & ! wat] is pump$ f ! settl+ bas9s to !m1 & aga9 f ! res]voir receiv+ ! efflu5ts f ! filt]s to ! city4 ,9 sev]al ( ! ,london works 7,ea/ ,london1 ,gr& ,junction1 ,s\?w>k & ,vauxhall1 etc47 ! settl+-bas9s are l[] ?an ! riv]1 & ! filt]s are /ill l[]1 s t a s+le pump+ suffices1 t com+ betwe5 ! filt] & ! city1 or elevat$ di/ribut+ res]voir4 ,9 _m o!r ,engli% filt]s & 9 mo/ ,g]man works ! settl+-bas9s & filt]s are plac$ toge!r a little high] ?an ! riv]1 ?us avoid+ at once tr\ble f floods & co/ = excavation4 ,! wat] requires to be pump$ twice1 once be=e & once aft] filtration4 ,at ,altona ! settl+-bas9s & filt]s are plac$ ^u a hill1 to :i* ! raw ,elbe wat] is pump$1 & f :i* x is suppli$ to ! city aft] filtration by gravity )\t fur!r pump+4 ,! location ( ! works 9 ?is case is said to h be5 det]m9$ by ! location ( a b$ ( s& suitable = filtration on ! spot :]e ! filt]s 7 built4 ,:5 two pump+s are requir$ !y are frequ5tly done1 especially 9 ! small] places1 9 ! same pump+-/ation1 ) b "o set ( boil]s & eng9es1 ! two pumps be+ connect$ to ! same eng9e4 ,! co/ is said to be only slightly great] ?an t ( a s+le lift ( ! same total height4 ,9 v l>ge works1 z at ,b]l9 & ,hamburg & "s ( ! ,london companies1 two sep>ate sets ( pump+ ma*9]y involve less extra co/ relatively ?an w\ld be ! case ) small] works4 ,,s$im5tation-,,bas9s4 ,kirkwood#b f\nd 9 #ahff t s$im5tation-bas9s 7 ess5tial to ! successful treatm5t ( turbid riv]-wat]s1 & subsequ5t exp]i5ce has n 9 any way %ak5 8 conclusion4 ,! ,g]man works visit$ by him1 ,b]l9 7,/ralau7 & ,altona1 7 bo? built by ,engli% eng9e]s1 & _! settl+-bas9s did n diff] mat]ially f ^? ( correspond+ works 9 ,engl&4 ,s9ce t "t1 h[ev]1 !re has be5 a well-m>k$ t5d5cy on ! "p ( ! ,g]man eng9e]s to use small]1 :ile ! ,engli% eng9e]s h us$ mu* l>g] s$im5tation-bas9s1 s t ! practices ( ! two c\ntries are n[ widely sep>at$1 ! diff]5ce no d\bt be+ 9 "p at lea/ due to local causes4 ,kirkwood f\nd s$im5tation-bas9s at ,altona ) a capacity ( #b-a_/d times ! daily supply4 ,9 #ahid ! same bas9s 7 9 use1 al?\gh ! filt]+ area _h be5 increas$ f #j4hb acre to #b4bj acres1 & /ill m filt]s 7 9 c\rse ( con/ruction1 & ! av]age daily quantity ( wat] _h increas$ f #fjj1jjj to #d1aej1jjj gallons 9 #ahia-b1 or m ?an ?ree times ! capacity ( ! s$im5tation-bas9s4 ,9 #ahij ! dep? ( mud deposit$ 9 ^! bas9s 0 report$ to be two feet deep 9 ?ree mon?s4 ,at ,/ralau 9 ,b]l91 also1 9 ! same "t ! filt]+ area 0 ne>ly d\bl$ )\t increas+ ! size ( ! s$im5tation-bas9s1 b ! ,spree at ?is po9t has su* a sl[ curr5t t x =ms itself a natural s$im5tation-bas94 ,at ,magdeburg on ! ,elbe works 7 built 9 #ahgf ) a filt]+ area ( #a4ib acres1 & a s$im5tation-bas9 capacity ( #aa1cjj1jjj gallons1 b 9 #ahid half ( ! latt] _h be5 built ov] into filt]s1 :i* ) two o!r filt]s gave a total filt]+ surface ( #c4ij acres1 ) a s$im5tation-bas9 capacity ( only #e1fej1jjj gallons4 ,! daily quantity ( wat] pump$ = #ahia-b 0 #e1jjj1jjj gallons1 s t ! pres5t s$im5tation-bas9 capacity is ab\t equal to "o day's supply1 or relatively less ?an a ?ird ( ! orig9al provision4 ,! idea foll[$ is t mo/ ( ! p>ticles :i* w settle at all w d s )9 tw5ty-f\r h\rs1 & t a great] /orage capacity may all[ ! gr[? ( alg1 & t ! wat] may det]iorate r ?an improve 9 l>g] tanks4 ,illu/ration3 ,,pav$ ,,embankm5t ,,betwe5 ,,two ,,filt]s1 ,,ea/ ,,london4 ,illu/ration3 ,,filt]s ,,& ,,*annels ,,= ,,raw ,,wat]1 ,,antw]p4 ,to face page #aj4 ,at ,london1 on ! o!r h&1 ! au?orities consid] a l>ge /orage capacity = unfilt]$ wat] z "o ( ! mo/ important conditions ( successful filtration1 ! object h[ev]1 be+ p]haps z mu* to secure /orage z to all[ s$im5tation4 ,9 #ahic ?irty-n9e places 7 report$ ^u ! ,?ames & ! ,lea :i* 7 giv+ _! sewage sy/ematic treatm5t be=e dis*>g+ x into ! /reams f :i* ,london's wat] is drawn4 ,^! sewage treatm5ts are1 ) h>dly an exception1 dry-wea!r treatm5ts1 & z soon z !re is a consid]able /orm crude sewage is dis*>g$ into ! riv]s at e po9t4 ,! riv]s are bo? %ort1 & are quickly flood$1 & aft]w>ds are soon back 9 _! usual condition4 ,at ^! times ( flood1 ! raw wat] is bo? v turbid & m pollut$ by sewage ?an at o!r times1 & x is ! aim ( ! au?orities to h ! wat] companies provide res]voir capacity en\gh to c>ry !m ?r\gh times ( flood )\t draw+ any wat] :atev] f ! riv]s4 ,?is obvi\sly involves mu* m ext5sive res]voirs ?an ^? us$ 9 ,g]many1 & ! companies actually h l>ge bas9s & are /ill add+ to !m4 ,! /orage capacities ( ! v>i\s companies v>y f #c to #ah times ! respective av]age daily supplies1 & toge!r equal #i times ! total supply4 ,9 case ! raw wat] is tak5 f a lake or a riv] at a po9t :]e !re is b little curr5t1 z 9 a natural or artificial pond1 s$im5tation-bas9s are unnecess>y4 ,?is is ! case at ,zri* 7lake wat]71 at ,b]l9 :5 ! riv]s ,havel & ,spree spread into lakes1 at ,tegel & ,mggel1 & at num]\s o!r works4 ,,size ,,( ,,filt]-,,b$s4 ,! total area ( filt]s requir$ 9 any case is calculat$ f ! quantity ( wat] requir$1 ! rate ( filtration1 & an all[ance = filt]s out ( use :ile be+ clean$4 ,to prev5t int]ruptions ( ! supply at times ( clean+1 ! filt]+ area is divid$ into b$s :i* are op]at$ sep>ately1 ! numb] & size ( ! b$s dep5d+ ^u local conditions4 ,! co/ p] acre is decreas$ ) l>ge b$s on acc\nt ( !re be+ less wall or embankm5t requir$1 :ile1 on ! o!r h&1 ! conv5i5ce ( op]ation may suff]1 especially 9 small works4 ,x is also frequ5tly urg$ t ) l>ge filt]s x is difficult or impossible to get an ev5 rate ( filtration ov] ! entire area ow+ to ! frictional resi/ance ( ! und]dra9s = ! m di/ant p>ts ( ! filt]4 ,a discussion ( ?is po9t is giv5 9 ,*apt] ,,iii1 page #da4 ,at ,hamburg1 :]e ! size ( ! s+le b$s1 #a4hh acres ea*1 is l>g] ?an at any o!r place1 x is %[n t !re is no s]i\s cause = anxiety2 & ev5 if !re 71 ! objectionable resi/ance c\ld be /ill f>!r r$uc$ by a few *anges 9 ! "u-dra9s4 ,! sizes ( filt]-b$s us$ at a l>ge numb] ( places are giv5 9 ,app5dix ,,iv4 ,at a numb] ( places hav+ sev]e w9t]s1 filt]s are vault$ ov] z a protection f cold1 & 9 ! mo/ important ( ^!1 ,b]l91 ,w>saw1 & ,/4 ,pet]sburg1 ! areas ( ! s+le b$s are ne>ly ! same1 namely1 f #j4eb to #j4ei acre4 ,! works ) op5 filt]s at ,london 7sev5 companies71 ,am/]dam1 & ,breslau h filt]-b$s f #j4hb to #a4ej acres ea*4 ,liv]pool & ,hamburg alone use filt]s ) some:at l>g] areas4 ,l>ge numb]s ( works ) bo? cov]$ & op5 filt]s h mu* small] b$s ?an ^! sizes1 b g5]ally ?is is to avoid too small a numb] ( divisions 9 a small total area1 al?\gh su* works h sometimes be5 ext5d$ ) ! gr[? ( ! cities until !y n[ h a consid]able numb] ( v small bas9s4 ,,=m ,,( ,,filt]-,,b$s4 ,! =m & con/ruction ( ! filt]-b$s dep5d ^u local conditions1 ! f\ndations1 & build+ mat]ials available1 ! pr9ciples gov]n+ ^! po9ts be+ 9 g5]al ! same z = ! con/ruction ( ord9>y res]voirs4 ,! bottoms require to be made wat]-tight1 ei!r by a ?9 lay] ( concrete or by a pavem5t ^u a puddle lay]4 ,= ! sides ei!r masonry walls or embankm5ts are us$1 ! =m] sav+ space1 b be+ 9 g5]al m exp5sive 9 con/ruction4 ,embankm5ts mu/1 ( c\rse1 be sub/antially pav$ ne> ! wat]-l9e to )/& ! action ( ice1 & mu/ n be injur$ by rapid fluctuations 9 ! wat]-levels 9 ! filt]s4 ,failure to make ! bottoms wat]-tight has p]haps caus$ m annoyance ?an any o!r s+le po9t4 ,) a leaky bottom !re is ei!r a loss ( wat] :5 ! wat] 9 ! filt]s is high] ?an ! gr\nd-wat]1 or "u rev]se conditions1 ! gr\nd-wat] comes 9 & mixes ) ! filt]$ wat]1 & ! latt] is r>ely improv$ & may be s]i\sly damag$ by ! admixture4 ,& ) v bad conditions wat] may pass f "o filt] to ano!r1 ) ! diff]5ces 9 pressure always exi/+ 9 neighbor+ filt]s1 ) mo/ unsatisfactory results4 ,,cov]s ,,= ,,filt]s4 ,! filt]s 9 ,engl& & ,holl& are built op51 )\t protection f ! wea!r4 ,9 ,g]many ! filt]s fir/ built 7 also op51 b 9 ! cold] climates m or less difficulty 0 exp]i5c$ 9 keep+ ! filt]s 9 op]ation 9 cold wea!r4 ,an addition to ! ,b]l9 filt]s1 built 9 #ahgd1 0 cov]$ ) masonry vault+1 ov] :i* sev]al feet ( e>? 7 plac$1 af=d+ a complete protection aga9/ fro/4 ,! filt]s at ,magdeburg built two ye>s lat] 7 cov]$ 9 ! same way1 & s9ce t "t cov]$ filt]s h be5 built at p]haps a doz5 diff]5t places4 ,illu/ration3 ,,int]ior ,,view ,,( ,,cov]$ ,,filt]1 ,,a%l&1 ,,wis4 ,:5 9 use ! wat] rises ne>ly to ! spr++ l9e ( ! ar*es4 ,illu/ration3 ,,cov]$ ,,filt] ,,9 ,,c\rse ,,( ,,con/ruction1 ,,%[+ ,,wood5 ,,c5t]s ,,= ,,masonry ,,vault+1 ,,som]swor?1 ,n4 ,h4 ,to face page #ab4 ,x 0 f\nd at ,b]l9 t1 ow+ to ! difficulty ( prop]ly clean+ ! op5 filt]s 9 w9t]1 x 0 impossible to keep ! usual proportion ( ! area 9 effective s]vice1 & z a result portions ( ! filt]s 7 greatly ov]tax$ dur+ prolong$ p]iods ( cold wea!r4 ,?is result$ 9 greatly decreas$ bact]ial effici5cy1 ! bact]ia 9 ,m>*1 #ahhi1 rea*+ #cjjj to #djjj p] cc4 7) #ajj1jjj 9 ! raw wat]71 al?\gh ord9>ily ! efflu5t conta9$ less ?an #ajj4 ,an epidemic ( typhoid fev] foll[$1 & 0 conf9$ to t "p ( ! city suppli$ f ! ,/ralau works1 ! w>ds suppli$ f ! cov]$ ,tegel filt]s rema9+ free f fev]4 ,op5 filt]s h s9ce be5 ab&on$ 9 ,b]l94 ,at ,altona also1 :]e ! wat] is tak5 f an excessively pollut$ s\rce1 decreas$ bact]ial effici5cy has repeat$ly result$ 9 w9t]1 & ! occasional epidemics ( typhoid fev] 9 t city1 :i* h inv>iably come 9 w9t]1 appe> to h be5 directly due to ! effect ( cold ^u ! op5 filt]s4 ,! city has j ext5d$ ! op5 filt]s1 & hopes ) an increas$ res]ve area to avoid ! difficulty 9 future )\t res\rce to cov]$ filt]s4 7,see ,app5dices ,,ii & ,,vii47 ,brunswick1 ,lbeck1 & ,frank=t on ,od] ) cold w9t]s h op5 filt]s1 b draw _! wat]-supplies f less pollut$ s\rces1 & h ?us f> escap$ ! fate ( ,b]l9 & ,altona4 ,! new filt]s at ,hamburg also are op54 ,at ,zri*1 :]e op5 & cov]$ filt]s 7 long us$ side by side1 ! cov]$ filt]s 7 mu* m satisfactory1 & ! old op5 filt]s h rec5tly be5 vault$ ov]4 ,knigsb]g orig9ally built op5 filt]s1 b 0 aft]w>d oblig$ to cov] !m1 on acc\nt ( ! sev]e w9t]s2 & at ,breslau1 :]e op5 filt]s h long be5 us$1 ! rec5t additions are vault$ ov]4 ,! fact t inf]ior effici5cy ( filtration results ) op5 filt]s dur+ prolong$ & sev]e w9t] wea!r is g5]ally admitt$1 al?\gh !re is "s d\bt z to ! exact way 9 :i* ! di/urbance is caus$4 ,9 "s works ,i am in=m$ t 9 cutt+ ! ice ar\nd ! edges ( ! filt] & repeat$ly pil+ ! loose pieces ^u ! float+ cake1 ! latt] ev5tually becomes s ?ick5$ at ! sides t ! project+ l[] corn]s actually t\* ! s&1 ) ! fluctuat+ levels :i* (t5 prevail 9 ^! works1 & t 9 ?is way ! s$im5t lay] ^u ! top ( ! s& is brok5 & ! wat] rapidly passes )\t adequate purification at ! po9ts ( di/urbance4 ,?is !ory is1 h[ev]1 inadequate to acc\nt = _m cases :]e su* an accumulation ( ice is n all[$4 ,9 ^! cases ! poor "w is n obta9$ until aft] ! filt]s h be5 scrap$4 ,! s& app>5tly freezes slightly :ile ! wat] is (f1 & :5 wat] is br\ght back & filtration resum$1 normal results are = "s reason n aga9 obta9$ = a "t4 ,9 addition to ! poor] "w f op5 filt]s 9 cold wea!r1 ! co/ ( remov+ ! ice adds mat]ially to ! op]at+ exp5ses1 & 9 v cold climates w\ld 9 itself make cov]s advisable4 ,i h arrang$ ! ,european filt] plants1 9 reg>d to :i* ,i h suffici5t in=mation1 9 ! table on page #ae1 9 ! ord] ( ! normal mean ,janu>y temp]atures ( ! respective places4 ,?is may n be an ideal crit]ion ( ! necessity ( cov]+ filt]s1 b x is at lea/ approximate1 & 9 ! abs5ce ( m detail$ comp>isons x w s]ve to give a good g5]al idea ( ! case4 ,i h n f\nd a s+le case :]e cov]$ filt]s are us$ :]e ! ,janu>y temp]ature is #cb ,f4 or above4 ,9 "s ( ^! places "s tr\ble is exp]i5c$ 9 unusually cold wea!r1 b ,i h n he>d ( any v s]i\s difficulty or ( any talk ( cov]+ filt]s at ^! places except at ,rott]dam1 :]e a project = cov]+ 0 be+ discuss$4 ,^? places hav+ ,janu>y temp]atures bel[ #cj exp]i5ce a great deal ( difficulty ) op5 filt]s2 s mu* s1 t cov]$ filt]s may be reg>d$ z necess>y = !m1 al?\gh x is possible to keep op5 filt]s runn+ ) decreas$ effici5cy & increas$ exp5se by freely remov+ ! ice1 ) ,janu>y temp]atures "s degrees l[]4 ,:]e ! mean ,janu>y temp]ature is #cj to #cb ,f4 !re is room = d\bt z to ! necessity ( cov]+ filt]s1 b1 judg+ f ! exp]i5ce ( ,b]l9 & ,altona1 ! cov]$ filt]s are mu* saf] at ?is temp]ature4 ,,table ,,( ,,places ,,hav+ ,,op5 ,,& ,,cov]$ ,,filt]s4 ,,arrang$ ,,accord+ ,,to ,,! ,,mean ,,janu>y ,,temp]atures4 ---------------------------------------- ---------------------------- ,normal ,mean ,janu>y ,place4 ,k9d ( ,filt]s & ,results4 ,temp]ature4 ,degrees ,f4 ---------------------------------------- ---------------------------- #cg-dj ,all ,engli% cities,op5 filt]s only are us$1 & no great difficulty ) ice is exp]i5c$4 #cc-ce ,cities 9 ,holl& ,all filt]s are op51 & !re is little s]i\s tr\ble ) ice2 b at ,am/]dam & ,rott]dam ! bact]ia 9 efflu5ts are said to be high] 9 w9t] ?an at o!r times4 #cb ,brem5 ,op5 filt]s4 #ca ,altona ,mu* difficulty ) ice 9 op5 filt]s 7see ,app5dices ,,ii & ,,vii74 #ca ,brunswick ,op5 filt]s4 #ca ,hamburg ,op5 filt]s4 #ca ,lbeck ,op5 filt]s4 #ca ,b]l9 ,op5 filt]s 7 =m]ly us$1 b ow+ to decreas$ effici5cy 9 cold wea!r !y h be5 ab&on$ = cov]$ ones4 #ca ,magdeburg ,cov]$ filt]s1 b a rec5t addition is n cov]$4 #cj ,frank=t on ,od] ,op5 filt]s4 #cj ,/uttg>t ,"p ( ! filt]s are cov]$4 #cj ,/ett9 ,"p ( ! filt]s are cov]$4 #bi ,zri* ,cov]$ filt]s 7 mu* ! mo/ satisfactory1 & ! op5 ones 7 cov]$ 9 #ahid4 ,! raw wat] has a temp]ature ( #ce4 #bi ,liegnitz ,op5 filt]s4 #bi ,breslau ,op5 filt]s h be5 us$1 b rec5t additions are cov]$4 #bi ,budape/ ,cov]$ filt]s only4 #bi ,pos5 ,cov]$ filt]s only4 #bf ,knigsb]g ,! orig9al filt]s 7 op51 b x 0 f\nd necess>y to cov] !m4 #bd ,w>saw ,cov]$ filt]s only4 #af ,/4 ,pet]sburg ,cov]$ filt]s only4 ---------------------------------------- ---------------------------- ,9 case ! raw wat] 0 drawn f a lake at a dep? :]e its m9imum temp]ature 0 above #cb1 :i* is ! temp]ature :i* mu/ ord9>ily be expect$ 9 surface-wat]s 9 w9t]1 op5 filt]s might be successfully us$ 9 slightly cold] places4 ,! cov]s are usually ( brick or concrete vault+ support$ by pill>s at di/ances ( #aa to #ae feet 9 ea* direction1 ! :ole be+ cov]$ by #b or #c feet ( e>?2 & ! top c be laid out z a g>d5 if desir$4 ,small holes = ! admission ( air & light are usually left at int]vals4 ,! ?ickness ( ! masonry & ! sizes ( ! pill>s us$ 9 "s ( ! e>li] ,g]man vault+s are unnecess>ily great1 & "s ( ! new] works are mu* light]4 ,= ,am]ican use1 vault+ l t us$ = ! ,newton1 ,mass41 cov]$ res]voir#c %\ld be amply /rong4 ,ro(s h be5 us$ at ,knigsb]g1 ,pos51 & ,budape/ in/ead ( ! masonry vault+4 ,!y are *eap]1 b d n af=d z good protection aga9/ fro/1 & ev5 ) great c>e "s ice w =m "u !m4 ,provision mu/ be made = ent]+ ! filt]s freely to introduce & remove s&4 ,?is is usually accompli%$ by rais+ "o section ( vault+ & build+ a p]man5t incl9e "u x f ! s& l9e to a door above ! high-wat] l9e 9 ! filt]4 ,! co/ ( build+ cov]$ filt]s is said to av]age fully "o half m ?an op5 filt]s4 ,among ! incid5tal advantages ( cov]$ filt]s is t ) ! comp>ative d>kness !re is no t5d5cy to alg gr[?s on ! filt]s 9 summ]1 & ! frequ5cy ( scrap+ is !re=e some:at r$uc$4 ,at ,zri*1 9 #ahib1 :]e bo? cov]$ & op5 filt]s 7 9 use side by side1 ! p]iods betwe5 scrap+s av]ag$ a ?ird long] 9 ! cov]$ ?an 9 ! op5 filt]s4 ,x has be5 suppos$ t cov]$ filt]s kept ! wat] cool 9 summ] & w>m 9 w9t]1 b ow+ to ! l>ge volume ( wat] pass+1 ! *ange 9 temp]ature 9 any case is v slight2 ,frhl+ f\nd t ev5 9 extreme cases a *ange ( ov] #c ,f4 9 ei!r direction is r>ely obs]v$4 ,illu/ration3 ,,remov+ ,,ice ,,f ,a ,,filt]1 ,,ea/ ,,london4 ,?is repres5ts ! greate/ accumulation ( ice 9 ! hi/ory ( ! works4 ,to face page #af4 ,at ,b]l91 :]e op5 & cov]$ filt]s 7 us$ side by side at ,/ralau = tw5ty ye>s1 x 0 f\nd t1 bact]ially1 ! op5 filt]s 71 except 9 sev]e w9t] wea!r1 m effici5t4 ,x 0 long suppos$ t ?is 0 caus$ by ! /]iliz+ action ( ! sunlight ^u ! wat] 9 ! op5 filt]s4 ,?is result1 h[ev]1 0 n confirm$ else:]e1 & x 0 f9ally discov]$1 9 #ahic1 t ! high] numb]s 7 due to ! exi/5ce ( passages 9 corn]s on ! columns ( ! vault$ ro( & ar\nd ! v5tilators = ! und]dra9s1 ?r\gh :i*1 practically1 unfilt]$ wat] f\nd its way into ! efflu5t4 ,?is at once removes ! evid5ce 9 favor ( ! sup]ior bact]ial effici5cy ( op5 filt]s & sugge/s ! necessity ( prev5t+ su* passages4 ,! con/ruction ( a l$ge all ar\nd ! walls & pill>s f\r in*es wide & a little above ! gravel1 z %[n 9 ! sket*1 might be useful 9 ?is way1 & ! slight lat]al movem5t ( ! wat] 9 ! s& above w\ld be ( no consequ5ce4 ,! s& w\ld evid5tly make a clos] jo9t ) ! horizontal l$ge ?an ) ! v]tical wall4 ,illu/ration3 ,,fig4 #b4 ,9 reg>d to ! probable requirem5t or advisability ( cov]s = filt]s 9 ! ,unit$ ,/ates1 ,i judge1 f ! ,european exp]i5ce1 t places hav+ ,janu>y temp]atures bel[ ! freez+-po9t w h consid]able tr\ble f op5 filt]s1 & w\ld be/ h cov]$ filt]s4 ,places hav+ high] w9t] temp]atures w be able to get along ) ! ice :i* may =m on op5 filt]s1 & ! con/ruction ( cov]s w\ld h>dly be advisable except "u exceptional local conditions1 z1 = in/ance1 ) a wat] ) an unusual t5d5cy to alg gr[?s4 ,i h drawn a l9e across a map ( ! ,unit$ ,/ates on ?is basis 7%[n by ! accompany+ plate7 & x w\ld appe> t places f> nor? ( ! l9e w\ld require cov]$ filt]s1 & t ^? s\? ( x w\ld n1 :ile = ! places 9 ! imm$iate vic9ity ( ! l9e 7comp>able to ,hamburg & ,altona7 !re is room = discussion4 ,9 ! ,unit$ ,/ates cov]$ filt]s h be5 con/ruct$ at ,/4 ,johnsbury1 ,vt41 ,som]swor?1 ,n4 ,h41 ,albany1 ,n4 ,y41 ,a%l&1 ,wis41 & ,gr& ,=ks1 ,n4 ,dak41 all ( ^! places be+ consid]ably nor? ( ! above-m5tion$ l9e4 ,! filt] at ,lawr5ce1 ,mass41 ) a mean ,janu>y temp]ature ( ab\t #be1 is n cov]$1 b s]i\s difficulty & exp5se h be5 exp]i5c$ at times f ! ice1 s mu* s t x has be5 repeat$ly recomm5d$ to cov] x4 ,op5 filt]s h also be5 9 use = _m ye>s at ,hudson & ,p\ghkeepsie1 ,n4 ,y41 ) mean ,janu>y temp]atures ab\t #bd2 & al?\gh consid]able difficulty has be5 exp]i5c$ f ice at times1 ^! filt]s1 p>ticul>ly ! ones at ,p\ghkeepsie1 h be5 kept 9 v s]viceable condition at all times1 not)/&+ ! ice4 ,at ,m\nt ,v]non1 ,n4 ,y41 ) a mean ,janu>y temp]ature ( ab\t #ca1 & ) a res]voir wat]1 no s]i\s difficulty has be5 exp]i5c$ ) ice2 & at ,f> ,rockaway1 ,l4 ,i41 ) a slightly high] temp]ature & well-wat]1 no difficulty :atev] has be5 exp]i5c$ ) op5 filt]s4 ,filt]s at ,ilion1 ,n4 ,y41 ) a mean ,janu>y temp]ature ( ab\t #bc1 are n cov]$1 & are f$ f a res]voir4 ,no s]i\s difficulty has be5 exp]i5c$ ) ice1 :i* is probably due to ! fact t ! wat] appli$ to !m is tak5 f ne> ! bottom ( ! res]voir1 & ord9>ily has a temp]ature some:at above ! freez+-po9t ?r\gh\t ! w9t]4 ,illu/ration3 ,map %[+ ,normal ,mean ,janu>y ,temp]atures ,,9 ,,! ,,unit$ ,,/ates & ! ,area 9 :i* ,filt]s %\ld be cov]$ ,! co/ ( remov+ ice f filt]s dep5ds1 among o!r ?+s1 ^u ! am\nt ( res]ve filt] area4 ,:5 ?is res]ve is small ! filt]s mu/ be kept con/antly at "w ne>ly up to _! rat$ capacity2 ! ice mu/ be remov$ promptly :5ev] ! filt]s require clean+1 & "u "s conditions ! exp5se ( do+ ?is may be consid]able4 ,if1 on ! o!r h&1 !re is a consid]able res]ve area1 s t :5 a filt] becomes clogg$ 9 sev]e wea!r1 ! "w c be turn$ ^u o!r filt]s & ! clogg$ filt] all[$ to rema9 until m mod]ate wea!r1 or until a ?aw1 ! exp5se ( ice removal may be kept at a mat]ially l[] figure4 ,9 case op5 filt]s are built ne> or nor? ( ?is l9e1 ,i w\ld sugge/ t pl5ty ( space betwe5 & ar\nd ! filt]s = pil+ up ice 9 case ( necessity may be f\nd advantage\s1 & t a great] res]ve ( filt]+ area = use 9 em]g5cies %\ld be provid$ ?an w\ld be consid]$ necess>y ) vault$ filt]s or ) op5 filt]s 9 a w>m] climate4 ,,*apt] ,,iii4 ,,filt]+ ,,mat]ials4 ,,s&4 ,! s& us$ = filtration may be obta9$ f ! sea-%ore1 f riv]-b$s or f s&-banks4 ,x consi/s ma9ly ( %>p qu>tz gra9s1 b may also conta9 h>d silicates4 ,z x occurs 9 nature x is frequ5tly mix$ ) clayey or o!r f9e p>ticles1 :i* mu/ be remov$ f x by wa%+ be=e x is us$4 ,"s ( ! ,new ,engl& s&s1 h[ev]1 z t us$ = ! ,lawr5ce ,city filt]1 are s clean t wa%+ w\ld be sup]flu\s4 ,! gra9 size ( ! s& be/ adapt$ to filtration has be5 v>i\sly /at$ at f #a_/h to #a mm41 or f #j4jac to #j4jdj in*4 ,! v>iations 9 ! figures1 h[ev]1 are due m to ! way t ! same s& appe>s to diff]5t obs]v]s ?an to actual v>iations 9 ! size ( s&s us$1 :i* are b a small fraction ( ^? indicat$ by ^! figures4 ,z a result ( exp]im5ts made at ! ,lawr5ce ,exp]im5t ,/ation#d we h a /&>d by :i* we c def9itely comp>e v>i\s s&s4 ,! size ( a s&-gra9 is uni=mly tak5 z ! diamet] ( a sph]e ( equal volume1 reg>dless ( its %ape4 ,z a result ( num]\s measurem5ts ( gra9s ( ,lawr5ce s&s1 x is f\nd t :5 ! diamet]1 z giv5 above1 is #a1 ! ?ree axes ( ! gra91 select+ ! longe/ possible & tak+ ! o!r two at "r angles to x1 are1 on an av]age1 #a4ch1 #a4je1 & #j4fi1 respectively & ! mean diamet] is equal to ! cube root ( _! product4 ,x 0 also f\nd t 9 mix$ mat]ials conta9+ p>ticles ( v>i\s sizes ! wat] is =c$ to g ar\nd ! l>g] p>ticles & ?r\gh ! f9] portions :i* occupy ! int]v5+ spaces1 s t x is ! f9e/ portion :i* ma9ly det]m9es ! "* ( ! s& = filtration4 ,z a provisional basis :i* be/ acc\nts = ! kn[n facts1 ! size ( gra9 su* t #aj p] c5t by weight ( ! p>ticles are small] & #ij p] c5t l>g] ?an itself1 is consid]$ to be ! effective size4 ,! size s calculat$ is uni=mly ref]r$ to 9 speak+ ( ! size ( gra9 9 ?is "w4 ,illu/ration3 ,,fig4 #c4--;,,app>atus ,,us$ ,,= ,,measur+ ,,! ,,friction ,,( ,,wat] ,,9 ,,s&s4 ,ano!r important po9t 9 reg>d to a mat]ial is its degree ( uni=mity--:e!r ! p>ticles are ma9ly ( ! same size or :e!r !re is a great range 9 _! diamet]s4 ,?is is %[n by ! uni=mity coeffici5t1 a t]m us$ to designate ! ratio ( ! size ( ! gra9 :i* has #fj p] c5t ( ! sample f9] ?an itself to ! size :i* has #aj p] c5t f9] ?an itself4 ,! frictional resi/ance ( s& to wat] :5 closely pack$1 ) ! pores completely fill$ ) wat] & 9 ! entire abs5ce ( clogg+1 0 f\nd to be express$ by ! =mula v cd#b7;h_/l77t ,fah4 #aj7_/fj1 :]e v is ! velocity ( ! wat] 9 met]s daily 9 a solid column ( ! same area z t ( ! s&1 or approximately 9 million gallons p] acre daily2 c is an approximately con/ant factor2 d is ! effective size ( s& gra9 9 millimet]s2 h is ! loss ( head 7,fig4 #c72 l is ! ?ickness ( s& ?r\gh :i* ! wat] passes2 t is ! temp]ature 7,fahr474 ,,table ,,%[+ ,,rate ,,at ,,:i* ,,wat] ,,w ,,pass ,,?r\gh ,,ev5-,,gra9$ ,,& ,,clean ,,s&s ,,( ,,! ,,/at$ ,,gra9 ,,sizes ,,& ,,) ,,v>i\s ,,heads ,,at ,a ,,temp]ature ,,( #ej4 ---------------------------------------- ----------------------------- ,effective ,size 9 ,millimet]s #aj p] c5t f9] ?an3 h_/l------------------------------------ ------------------- #j4aj #j4bj #j4cj #j4ce #j4dj #j4ej #a4jj #c4jj ---------------------------------------- ---------------------- ,million ,gallons p] ,acre daily4 4#jja 4#ja 4#jd 4#aj 4#ac 4#ag 4#bg #a4jg #i4fc 4#jje 4#je 4#ba 4#dh 4#fe 4#he #a4cd #e4ce #dh4ae 4#jaj 4#aa 4#dc 4#if #a4ca #a4ga #b4fg #aj4gj #if4cj 4#jej 4#ed #b4ad #d4hb #f4ee #h4ee #ac4dj #ec4ej 4#ajj #a4jg #d4bh #i4fc #ac4aj #ag4aj #bf4gj #ajg4jj #a4jjj #aj4gj #db4hj #if4cj #aca4jj #aga4jj #bfg4jj ---------------------------------------- ---------------------- ,! above table is comput$ ) ! value c tak5 z #ajjj1 ?is be+ approximately ! values d$uc$ f ! e>lie/ exp]im5ts4 ,m rec5t & ext5d$ data h %[n t ! value ( c is n entirely con/ant1 b dep5ds ^u ! uni=mity coeffici5t1 ^u ! %ape ( ! s& gra9s1 ^u _! *emical composition1 & ^u ! cleanl9ess & clos5ess ( pack+ ( ! s&4 ,! value may be z high z #abjj = v uni=m1 & p]fectly clean s&1 & maybe z l[ z #djj = v closely pack$ s&s conta9+ a good deal ( alum9a or iron1 & especially if !y are n q clean4 ,! friction is usually less 9 new s& ?an 9 s& :i* has be5 9 use = "s ye>s4 ,9 mak+ computations ( ! frictional resi/ance ( filt]s1 ! av]age value ( c may be tak5 at f #gjj to #ajjj = new s&1 & f #ejj to #gjj = s& :i* has be5 9 use = a numb] ( ye>s4 ,! value ( c decreases z ! uni=mity coeffici5t increases4 ,) ord9>y filt] s&s ) uni=mity coeffici5ts ( #c or less ! diff]5ces are n great4 ,) mix$ s&s hav+ mu* high] uni=mity coeffici5ts1 l[] & less con/ant values ( c are obta9$1 & ! arrangem5t ( ! p>ticles becomes a controll+ factor 9 ! increase 9 friction4 ,! friction ( ! surface lay] ( a filt] is (t5 great] ?an t ( all ! s& bel[ ! surface4 ,x mu/ be sep>ately comput$ & add$ to ! resi/ances comput$ by ! =mula1 z x dep5ds l>gely ^u o!r conditions ?an ^? controll+ ! resi/ance ( ! s&4 ,:ile ! value ( c is ?us n entirely con/ant1 x c be e/imat$ ) approximate accuracy = v>i\s conditions1 f a k ( ! composition1 condition1 & cleanl9ess ( ! s&1 & clos5ess ( pack+4 ,! foll[+ table %[s ! quantity ( wat] pass+ s&s at diff]5t temp]atures4 ,?is table 0 comput$ ) temp]ature factors z giv5 above1 :i* 7 bas$ ^u exp]im5ts ^u ! fl[ ( wat] ?r\gh s&s1 *eck$ by ! coeffici5ts obta9$ f exp]im5ts ) long capill>y tubes entirely subm]g$ 9 wat] ( ! requir$ temp]ature4 ,,relative ,,quantities ,,( ,,wat] ,,pass+ ,,at ,,diff]5t ,,temp]atures4 #cb #j4gj #ce #j4ge #ch #j4hj #da #j4he #dd #j4ij #dg #j4ie #ej #a4jj #ec #a4je #ef #a4aj #ei #a4ae #fb #a4bj #fe #a4be #fh #a4cj #ga #a4ce #gd #a4dj #gg #a4de ,! effect ( temp]ature ^u ! passage ( wat] ?r\gh s&s & soils has be5 fur!r discuss$ by ,pr(4 ,l4 ,g4 ,c>p5t]1 ,eng9e]+ ,news1 ,vol4 ,,xxxix1 p4 #dbb4 ,?is article reviews briefly ! lit]ature ( ! subject1 & ref]s at l5g? to ! =mula ( ,poiseuille1 publi%$ 9 ! ,memoires des ,savants ,etrang]s1 ,vol4 ,,xi1 p4 #dcc 7#ahdf74 ,?is =mula1 9 :i* ! quantity ( wat] pass+ at #j4j ,c5t41 is tak5 z unity1 is z foll[s3 ,temp]ature factor #a #j4jccfgit #j4jjjbbat#b4 ,! results obta9$ by ?is =mula agree v closely ) ^? giv5 9 ! above table ?r\gh\t ! temp]ature range = :i* computations are mo/ frequ5tly requir$4 ,at ! high] & l[] temp]atures ! div]g5cies are great]1 z is %[n 9 a communication 9 ! ,eng9e]+ ,news1 ,vol4 ,,xl1 p4 #bf4 ,! quantity ( wat] pass+ at a temp]ature ( #ej ,fahr4 is 9 _m respects m conv5i5t z a /&>d ?an ! quantity pass+ at ! freez+-po9t4 ,ne> ! freez+-po9t1 ow+ to molecul> *anges 9 ! wat]1 ! *anges 9 its action are rapid1 & ! results are less c]ta91 & also #ej ,fahr4 is a mu* m conv5i5t temp]ature = precise exp]im5ts ?an is ! freez+ po9t4 ,,s&s ,,us$ ,,9 ,,european ,,filt]s4 ,to secure def9ite in=mation 9 reg>d to ! qualities ( ! s&s actually us$ 9 filtration1 a l>ge numb] ( ,european works 7 visit$ 9 #ahid1 & samples ( s& 7 collect$ = analysis4 ,^! samples 7 exam9$ at ! ,lawr5ce ,exp]im5t ,/ation by ,mr4 ,h4 ,w4 ,cl>k1 ! au?or's me?od ( analysis describ$ 9 ,app5dix ,,iii be+ us$4 ,9 ! foll[+ table1 = ! sake ( compactness1 only ! lead+ po9ts ( ! analyses1 namely1 effective size1 uni=mity coeffici5t1 & album9oid ammonia1 are giv54 ,on page #bh full analyses ( "s samples f a few ( ! lead+ works are giv54 ,,analyses ,,( ,,s&s ,,us$ ,,9 ,,wat] ,,filtration4 ---------------------------------------- -------------------------- ,effective ,albu- ,size2 #aj ,uni- m9oid ,f9] =mity ,ammo- ,s\rce4 ?an ,coeffi- nia4 ,rem>ks4 7,milli- ci5t4 ,p>ts 9 met]s74 #ajj1jjj4 ---------------------------------------- -------------------------- ,london1 ,e4 ,london ,co4 #j4dd #a4h #j4de ,new s&1 nev] us$ or wa%$4 ,london1 ,e4 ,london ,co4 #j4ci #b4a #bf4bj ,dirty s&1 v old4 ,london1 ,e4 ,london ,co4 #j4cg #b4j #h4fj ,same1 wa%$ by h&4 ,london1 ,gr& ,junc4 #j4bf #a4i #a4ij ,s& f r\gh filt]4 ,london1 ,gr& ,junc4 #j4dj #c4e #aj4jj ,old s& 9 f9al filt]4 ,london1 ,gr& ,junc4 #j4da #c4g #b4gj ,fre%ly wa%$ old s&4 ,london1 ,s\?w'k ,v4 #j4ch #c4e #e4jj ,fre%ly wa%$ old s&4 ,london1 ,s\?w'k ,v4 #j4cj #a4h #b4hj ,fre%ly wa%$ new s&4 ,london1 ,lambe? #j4cf #b4c #b4fj ,fre%ly wa%$ old s&4 ,london1 ,lambe? #j4cf #b4d #j4ce ,new unus$ s&1 wa%$4 ,london1 ,lambe? #j4be #a4g #j4gj ,new extremely f9e s&4 ,london1 ,*elsea #j4cf #b4d #b4aj ,fre%ly wa%$ old s&4 ,middlesbor\gh #j4db #a4f #ag4fj ,dirty s&1 ord9>y scrap+4 ,middlesbor\gh #j4dc #a4f #g4cj ,same1 aft] wa%+4 ,birm+ham #j4bi #a4i #cc4bj ,dirty s&4 ,birm+ham #j4bi #a4i #g4bj ,s& bel[ surface ( filt]4 ,read+ #j4cj #b4e #d4jj ,dirty s&4 ,read+ #j4bb #b4j #a4ej ,same1 aft] wa%+4 ,antw]p #j4ch #a4f #g4hj ,dirty s&4 ,antw]p #j4ci #a4f #c4dj ,same1 aft] wa%+4 ,hamburg #j4bh #b4e #h4ej ,dirty s&4 ,hamburg #j4ca #b4c #j4hj ,same1 aft] wa%+4 ,hamburg #j4cd #b4b #g4ij ,dirty s&1 ano!r sample4 ,hamburg #j4cj #b4j #j4ij ,same1 aft] wa%+ drums4 ,hamburg #j4cd #b4c #a4ej ,same1 aft] wa%+ ejectors4 ,altona #j4cb #b4j #i4jj ,dirty s&1 old filt]s4 ,altona #j4cg #b4j #a4ej ,same1 aft] wa%+4 ,altona #j4cc #b4h #j4ej ,wa%$ s& = new filt]s4 ,b]l91 ,/ralau #j4cc #a4i #ab4bj ,dirty s&-pile4 ,b]l91 ,/ralau #j4ce #a4g #d4ej ,filt] ,no4 #f1 #c bel[ surface4 ,b]l91 ,/ralau #j4cd #a4g #f4cj ,filt] ,no4 #g1 #c bel[ surface4 ,b]l91 ,/ralau #j4ce #a4g #d4jj ,filt] ,no4 #aj1 #c bel[ surface4 ,b]l91 ,tegel #j4ch #a4f #aa4jj ,dirty s&1 old filt]s4 ,b]l91 ,tegel #j4ch #a4e #b4hj ,same1 aft] wa%+1 old filt]s4 ,b]l91 ,tegel #j4ce #a4f #c4bj ,same1 aft] wa%+1 new filt]s4 ,b]l91 ,mggel #j4ce #a4h #j4hj ,s& f filt]s bel[ surface4 ,b]l91 ,mggel #j4cc #b4j #f4cj ,dirty s&1 ord9>y scrap+4 ,b]l91 ,mggel #j4cd #b4j #ae4cj ,dirty s&1 ano!r sample4 ,*>lott5burg #j4dj #b4c #g4bj ,dirty s&4 ,*emnitz #j4ce #b4f #j4bj ,new s& n yet us$4 ,magdeburg #j4ci #b4j #i4ej ,dirty s&4 ,magdeburg #j4dj #b4j #b4hj ,same1 aft] wa%+4 ,breslau #j4ci #a4h #a4dj ,normal new s&4 ,budape/ #j4bj #b4j #j4hj ,new wa%$ ,danube s&4 ,zri* #j4bh #c4b #f4bj ,dirty s&4 ,zri* #j4cj #c4a #a4ej ,same1 aft] wa%+4 ,hague #j4ai #a4f #j4gj ,dune-s& us$ = filtration4 ,s*i$am #j4ah #a4f #e4fj ,dune-s& us$ = filtration2 dirty4 ,s*i$am #j4ca #a4e #ac4ej ,riv]-s&2 dirty4 ,am/]dam #j4ag #a4f #b4dj ,dune-s&4 ,rott]dam #j4cd #a4e #b4cj ,riv]-s&2 new4 ,liv]pool1 ,riv+ton #j4dc #b4j #j4gf ,s& f bottom ( filt]4 ,liv]pool1 ,riv+ton #j4cb #b4e #a4jj ,new s& unwa%$ & unscre5$4 ,liv]pool1 ,riv+ton #j4dc #b4g #d4aj ,wa%$ s& :i* has be5 9 use #cj to #dj ye>s4 ,liv]pool1 ,oswe/ry #j4cj #b4f #i4dj ,dirty s&4 ,liv]pool1 ,oswe/ry #j4ca #d4g #b4bj ,same1 aft] wa%+4 ---------------------------------------- -------------------------- ,,note4--,x is obvi\s t 9 case ! s&s us$ at any place are n always ( ! same "*1 z is %[n to be ! case by diff]5t samples f "s ( ! works1 ! exam9ation ( su* a limit$ numb] ( samples z ! above f ea* place is entirely inadequate to e/abli% accurately ! sizes ( s& us$ at t p>ticul> place1 or to all[ close comp>isons betwe5 ! diff]5t works1 & = ?is reason no su* comp>isons w be made4 ,! object ( ^! inve/igations 0 to det]m9e ! sizes ( ! s&s commonly us$ 9 ,europe1 &1 consid]+ ! numb] & "* ( ! diff]5t works repres5t$1 x is believ$ t ! results are ample = ?is purpose4 ,! ,engli% & mo/ ( ! ,g]man s&s are wa%$1 ev5 :5 entirely new1 be=e be+ us$1 to remove f9e p>ticles4 ,at ,breslau1 h[ev]1 s& dr$g$ f ! riv] ,od] is us$ 9 its natural /ate1 & new s& is us$ = replac+ t remov$ by scrap+4 ,at ,budape/1 ,danube s& is us$ 9 ! same way1 b ) a v crude wa%+1 & x is said t only new unwa%$ s& is us$ at ,w>saw4 ,9 ,holl&1 s f> z ,i le>n$1 no s& is wa%$1 b new s& is always us$ = refill+4 ,at mo/ ( ! works visit$ dune-s& ) an effective size ( only #j4ag to #j4ai mm4 is us$1 & ?is is ! f9e/ s& :i* ,i h ev] f\nd us$ = wat] filtration on a l>ge scale4 ,x %\ld be said1 h[ev]1 t ! wat]s filt]$ ?r\gh ^! f9e s&s are fairly cle> be=e filtration1 & are n comp>able to ! turbid riv]-wat]s (t5 filt]$ else:]e1 & _! t5d5cy to *oke ! filt]s is consequ5tly mu* less4 ,at ,rott]dam & ,s*i$am1 :]e ! raw wat] is drawn f ! ,maas1 z ! pr9cipal /ream ( ! ,rh9e is call$ 9 ,holl&1 riv]-s& ( mu* l>g] gra9 size is employ$4 ,x is obta9$ by dr$g+ 9 ! riv] & is nev] wa%$1 new s& always be+ employ$ = refill+4 ,! av]age results ( ! complete analyses ( s&s f t5 lead+ works are %[n 9 ! table on page #bh4 ,^! figures are ! av]age ( all ! analyses = ! respective places1 except t "o sample f ! ,lambe? ,co41 :i* 0 n a repres5tative "o1 0 omitt$4 ,! ,london companies 7 select$ = ?is comp>ison bo? on acc\nt ( _! long & favorable records 9 filt]+ ! pollut$ wat]s ( ! ,?ames & ,lea1 & because !y are subject to close inspection2 & !re is ample evid5ce t ! filtration obta9$ is good--evid5ce :i* is (t5 lack+ 9 ! small] & less closely wat*$ works4 ,= ! ,g]man works ,altona 0 select$ because ( its escape f *ol]a 9 #ahib1 due to ! effici5t action ( its filt]s1 & ,/ralau because ( its long & favorable record :5 filt]+ ! mu*-pollut$ ,spree wat]4 ,^! two works also h p]haps contribut$ m to ! mod]n !ories ( filtration ?an all ! o!r works 9 exi/5ce4 ,! rema9+ works are includ$ because !y are comp>atively new1 & h be5 con/ruct$ ) ! greate/ c>e & att5tion to details ?r\gh\t1 & ! results obta9$ are mo/ c>efully record$4 ,"s ( ! mo/ int]e/+ ( ^! results are %[n graphically on page #bi4 ,! me?od ( plott+ is t describ$ 9 ,app5dix ,,iii4 ,,table ,,%[+ ,,! ,,av]age ,,p] ,,c5t ,,( ,,! ,,gra9s ,,f9] ,,?an ,,v>i\s ,,sizes ,,9 ,,s&s ,,f ,,lead+ ,,works4 ---------------------------------------- -------------------------- ,p] ,c5t by ,weight ,f9] ?an ---------------------------------------- ----- #j4ajf #j4ahf #j4caf #j4df #j4ic #b4jd #c4hi #e4hi mm4 mm4 mm4 mm4 mm4 mm4 mm4 mm4 ---------------------------------------- ------------------- ,ea/ ,london #j4b #j4e #c4f #bb4b #fi4g #hi4h #ie4j #ii4j ,gr& ,junction #j #j4b #c4a #ag4d #dg4a #fh4b #hd4g #ic4f ,s\?w>k & ,vauxhall #j4g #h4j #cd4a #fi4g #hc4e #ij4j #id4j ,lambe? #j #j4e #e4e #bf4f #fc4j #gi4b #hh4j #id4c ,*elsea #j #j4a #e4j #bh4f #fc4j #gf4g #hf4j #ic4f ,hamburg #j4b #a4e #aj4i #cc4b #gd4d #ie4g #ii4e ,altona #j4a #a4a #g4h #bh4g #gb4a #ib4a #ie4h ,/ralau #j4c #g4j #cg4c #hf4i #ie4d #ig4f ,tegel #j4b #d4e #ce4d #id4c #ih4e #ii4a ,mggel #j4a #j4e #g4i #cc4f #gi4g #id4c #ih4e ---------------------------------------- ----- ,av]age ( all #j4jf #j4ef #f4cc #bi4gaga4iihg4cdic4db7ig4de7 ---------------------------------------- ------------------- ,,av]age ,,effective ,,size1 ,,uni=mity ,,coeffici5t1 ,,& ,,album9oid ,,ammonia ,,9 ,,s&s ,,f ,,t5 ,,lead+ ,,works4 ,i4 ,,london ,,filt]s4 ---------------------------------------- --------------------------- ,effective ,uni=mity ,album9oid ,ammonia4 ,size2 #aj ,coeffici5t4------------------ ,f9] ?an ,dirty ,s&4,wa%$ 7,millimet]s74 ,s&4 ---------------------------------------- -------------------------- ,ea/ ,london #j4dj #b4j #bf4jj #h4fj ,gr& ,junction #j4dj #c4f #aj4jj #b4gj ,s\?w>k & ,vauxhall #j4cd #b4e #c4ij ,lambe? #j4cf #b4d #b4fj ,*elsea #j4cf #b4d #b4aj ---------------------------------------- ---- ,av]age #j4cg #b4f #ah4jj #c4ih ---------------------------------------- -------------------------- ,,ii4 ,,g]man ,,works4 ---------------------------------------- -------------------------- ,/ralau #j4cd #a4g #ab4bj #d4jj ,tegel #j4cg #a4f #aa4jj #c4jj ,mggel #j4cd #b4j #aj4hj #j4hj ,altona #j4cd #b4c #i4jj #a4ej ,hamburg #j4ca #b4c #h4bj #a4jg ---------------------------------------- ---- ,av]age #j4cd #b4j #aj4be #b4jg ---------------------------------------- -------------------------- ,illu/ration3 ,,plac+ ,,s& ,,9 ,a ,,filt]1 ,,hamburg4 ,to face page #bh4 ,! av]ages %[ ! effective size ( ! ,engli% s&s to be slightly great] ?an t ( ! ,g]man s&s--#j4cg in/ead ( #j4cd mm4--b ! diff]5ce is v small4 ,! entire range = ! t5 works is only f #j4ca to #j4dj mm41 & ^! may be tak5 z ! ord9>y limits ( effective size ( ! s&s employ$ 9 ! be/ ,european works4 ,! av]age = ! o!r sixte5 works giv5 above1 includ+ dune-s&s1 is #j4ca mm41 or1 omitt+ ! dune-s&s1 #j4cd mm4 ,illu/ration3 ,,fig4 #c;a4--,,s& ,,analysis ,,%eet1 ,,) ,,analyses ,,( ,,sev]al ,,european ,,filt] ,,s&s4 ,x is important t filt] s&s %\ld be free f lime4 ,:5 wat] is filt]$ ?r\gh su* s&s1 no increase 9 h>dness results4 ,:51 h[ev]1 wat] is filt]$ ?r\gh s& conta9+ lime1 "s ( x is usually dissolv$ & ! wat] is made h>d]4 ,! am\nt ( lime tak5 up 9 ?is way dep5ds bo? ^u ! "* ( ! s&1 & ^u ! solv5t p[] ( ! wat]2 & x does n necess>ily foll[ t a s& conta9+ lime _c be us$ = filtration1 b a s& ne>ly free f lime is to be pref]r$4 ,! pres5ce ( lime 9 s& c usually be detect$ by moi/5+ x ) hydro*loric acid4 ,! evolution ( gas %[s ! pres5ce ( lime4 ,"s idea ( ! am\nt ( lime c be obta9$ f ! am\nt ( gas giv5 (f1 & ! appe>ance ( ! sample aft] ! treatm5t1 b *emical analysis is necess>y to det]m9e correctly ! am\nt4 ,exp]im5ts ) filt]s at ,pittsburg 7 made ) s& conta9+ #a4c p] c5t ( lime1 ! result be+ t ! h>dness ( ! wat] 0 increas$ ab\t "o "p 9 #ajj1jjj2 b ! am\nt ( lime 9 ! s& 0 s small t x w\ld be wa%$ out aft] a "t1 & !n ! h>d5+ effect w\ld cease4 ,l>g] am\nts ( lime w\ld cont9ue _! action = a numb] ( ye>s & w\ld be m objectionable4 ,turn+ to ! circum/ances :i* influ5ce ! selection ( ! s& size1 we f9d t bo? ! quality ( ! efflu5t obta9$ by filtration & ! co/ ( filtration dep5d ^u ! size ( ! s&-gra9s4 ,) a f9e s& ! s$im5t lay] =ms m quickly & ! removal ( bact]ia is m complete1 b1 on ! o!r h&1 ! filt] clogs quick] & ! dirty s& is m difficult to wa%1 s t ! exp5se is increas$4 ,,effect ,,( ,,size ,,( ,,gra9 ,,^u ,,effici5cy ,,( ,,filtration4 ,x is frequ5tly /at$ t x is only ! s$im5t lay] :i* p]=ms ! "w ( filtration1 & t ! s& :i* supports x plays h>dly a l>g] "p ?an does ! gravel :i* c>ries ! s&1 & "u "s circum/ances ?is is und\bt$ly ! case4 ,nev]!less s& 9 itself1 )\t any s$im5t lay]1 especially :5 n too co>se & n 9 too ?9 lay]s1 has v great purify+ p[]s1 &1 9 addition1 acts z a safegu>d by positively prev5t+ excessive rates ( filtration on acc\nt ( its frictional resi/ance4 ,z an illu/ration take ! case ( a filt] ( s& ) an effective size ( #j4ce mm4 & ! m9imum ?ickness ( s& all[$ by ! ,g]man ,bo>d ( ,heal?1 namely1 "o foot1 & let u suppose t ) clogg+ ! loss ( head has rea*$ two feet to produce ! desir$ velocity ( #b4eg million gallons p] acre daily4 ,suppose n[ t by "s accid5t ! s$im5t lay] is sudd5ly brok5 or remov$ f a small area1 ! wat] w ru% ?r\gh ?is area1 until a new s$im5t lay] is =m$1 at a rate correspond+ to ! size1 pressure1 & dep? ( ! s&1 or #bfj million gallons p] acre daily--a hundr$ times ! /&>d rate4 ,"u ^! conditions ! pass+ wat] w n be purifi$1 b w pollute ! entire efflu5t f ! filt]4 ,"u correspond+ conditions1 ) a deep filt] ( f9e s&1 say ) an effective size ( #j4bj mm4 & #e feet deep1 ! result+ rate w\ld be only #ag million gallons p] acre daily1 or less ?an sev5 times ! normal1 & ) ! wat] pass+ ?r\gh ! full dep? ( f9e s&1 ! result+ det]ioration 9 ! efflu5t be=e ! s& aga9 became s clogg$ z to r$uce ! rate to ne>ly ! normal1 w\ld be h>dly appreciable4 ,! results at ,lawr5ce h %[n t ) v f9e s&s #j4ji & #j4ad mm41 & #d to #e feet deep1 ) ! quantity ( wat] :i* c practically be made to pass ?r\gh !m1 x is almo/ impossible to drive m ?an an insignificant fraction ( ! bact]ia into ! efflu5t4 ,ev5 :5 ! s&s are entirely new1 or h be5 scrap$ or di/urb$ 9 ! mo/ viol5t way1 ! fir/ efflu5t pass+1 be=e ! s$im5t lay] c\ld h be5 =m$1 is ( good quality4 ,/ill f9] mat]ials1 #j4jd to #j4jf mm41 z f> z c\ld be det]m9$1 secur$ ! absolute removal ( all bact]ia1 b ! rates ( filtration :i* 7 possible 7 s l[ z to preclude _! practical application4 ,) co>s] s&s1 z long z ! filt] is kept at a /eady rate ( filtration1 )\t int]ruptions ( any k9d1 entirely satisfactory results are (t5 obta9$1 al?\gh nev] q s good z ) ! f9] s&s4 ,?us at ,lawr5ce ! p]c5tages ( bact]ia 7,b4 prodigiosus7 appe>+ 9 ! efflu5ts "u comp>able conditions 7 z foll[s3 #ahib #ahic ,) effective gra9 size #j4ch mm 4444 #j4af ,) effective gra9 size #j4bi mm 4444 #j4af ,) effective gra9 size #j4bf mm 4444 #j4aj ,) effective gra9 size #j4bj mm #j4ac #j4ja ,) effective gra9 size #j4ad mm #j4jd #j4jc ,) effective gra9 size #j4ji mm #j4jb #j4jb ,we may ?us conclude t f9e s&s give normally some:at bett] efflu5ts ?an co>s] ones1 & t !y are mu* m likely to give at lea/ a tol]ably good purification "u unusual or improp] conditions4 ,,effect ,,( ,,gra9 ,,size ,,^u ,,frequ5cy ,,( ,,scrap+4 ,! practical objection to ! use ( f9e s& is t x becomes rapidly clogg$1 s t filt]s require to be scrap$ at %ort] int]vals1 & ! s& wa%+ is mu* m difficult & exp5sive4 ,! quantities ( wat] filt]$ betwe5 successive scrap+s at ,lawr5ce 9 millions ( gallons p] acre "u comp>able conditions h be5 z foll[s3 #ahib #ahic ,effective size ( s& gra9 #j4ch mm 4444 #gi ,effective size ( s& gra9 #j4bi mm 4444 #gj ,effective size ( s& gra9 #j4bf mm 4444 #eg ,effective size ( s& gra9 #j4bj mm #eh 4444 ,effective size ( s& gra9 #j4ad mm #de #di ,effective size ( s& gra9 #j4ji mm #bd #ad ,! increase 9 ! quantities pass$ betwe5 scrap+s ) increas+ gra9 size is v m>k$4 ,) ! f9e s&s1 ! dep? to :i* ! s& becomes dirty is mu* less ?an ) ! co>se s&s1 b z x is n g5]ally practicable to remove a lay] ( s& less ?an ab\t #j4f in* ?ick1 ev5 :5 ! actual clogg$ lay] is ?9n] ?an ?is1 ! full quantity ( s& has to be remov$2 & ! quantities ( s& to be remov$ & wa%$ are inv]sely proportional to ! quantities ( wat] filt]$ betwe5 scrap+s4 ,on ! o!r h&1 ) v co>se s&s ! s$im5t p5etrates ! s& to a great] dep? ?an ! #j4f in* necess>ily remov$1 s t a ?ick] lay] ( s& has to be remov$1 :i* may m ?an (fset ! long] int]val4 ,?is happ5s occasionally 9 wat]-works1 & a s& co>se en\gh to all[ x occur is always dislik$ by sup]9t5d5ts1 & is replac$ ) f9] s& z soon z possible4 ,x is obvi\s t ! m9imum exp5se = clean+ w be secur$ ) a s& :i* j does n all[ ?is deep p5etration1 & ,i am incl9$ to ?9k t ! sizes ( ! s&s 9 use h actually be5 det]m9$ m (t5 ?an o!rwise 9 ?is way1 & t ! co>se/ samples f\nd1 hav+ effective sizes ( ab\t #j4dj mm41 repres5t ! practical limit to ! co>s5ess ( ! s&1 & t any increase above ?is size w\ld be foll[$ by increas$ exp5se = clean+ z well z by decreas$ effici5cy4 ,,selection ,,( ,,s&4 ,9 select+ a s& = filtration1 :5 x is consid]$ t repeat$ wa%+s w remove "s ( ! f9e/ p>ticles1 & s increase slightly ! effective size1 a new s& co>s] ?an #j4ce mm4 w\ld h>dly be select$4 ,p]haps #j4bj might be giv5 z a suitable l[] limit4 ,= comp>atively cle> lake- or res]voir-wat]s a f9] s& c\ld probably be us$ ?an w\ld be ! case ) a turbid riv]-wat]4 ,a mix$ s& hav+ a uni=mity coeffici5t above #c4j w\ld be difficult to wa% )\t sep>at+ x into portions ( diff]5t sizes1 &1 9 g5]al1 ! l[] ! coeffici5t1 t is1 ! m uni=m ! gra9 sizes1 ! bett]4 ,great pa9s %\ld be tak5 to h ! s& ( ! same quality ?r\gh\t1 especially 9 ! same filt]1 z any v>iations 9 ! gra9 sizes w\ld lead to important v>iations 9 ! velocity ( filtration1 ! co>s] s&s pass+ m ?an _! %>e ( wat] 79 proportion to ! squ>e ( ! effective sizes7 & ) r$uc$ effici5cy4 ,at ,lawr5ce a suffici5t quantity ( natural s& 0 f\nd ( ! grade requir$2 b :]e suitable mat]ial _c be s obta9$ x is necess>y to use o!r me?ods4 ,a mix$ mat]ial c be scre5$ f p>ticles :i* are too l>ge1 & c be wa%$ to free x f its f9] portions1 & 9 ?is way a good s& c be prep>$1 if necess>y1 f :at might seem to be q unpromis+ mat]ial4 ,! me?ods ( s&-wa%+ w be describ$ 9 ,*apt] ,v4 ,,?ickness ,,( ,,! ,,s& ,,lay]4 ,! ?ickness ( ! s& lay] is made s great t :5 x is repeat$ly scrap$ 9 clean+ ! s& w n become too ?9 = good filtration = a consid]able "t4 ,:5 ?is occurs ! remov$ s& mu/ be replac$ ) clean s&4 ,! orig9al ?ickness ( ! s& 9 ,european filt]s is usually f #bd to #dh in*es1 ?icknesses betwe5 #cj & #dj in*es be+ extremely common1 & ?is is r$uc$ be=e refill+ to f #ab to #bd in*es4 ,! ,imp]ial ,bo>d ( ,heal? ( ,g]many has fix$ #ab in*es z a limit bel[ :i* ! s& %\ld nev] be scrap$1 & a high] limit is recomm5d$ :]ev] possible4 ,a ?ick s& lay] has ! same /eady+ action z a f9e s&1 & t5ds to prev5t irregul>ities 9 ! rate ( filtration 9 proportion to its frictional resi/ance1 & t )\t increas+ ! frequ5cy ( clean+2 b1 on ! o!r h&1 x increases ! necess>y height ( ! filt]1 ?r\gh\t1 & consequ5tly ! co/ ( con/ruction4 ,9 addition to ! /eady+ effect ( a deep s& lay]1 "s purification takes place 9 ! l[] "p ( ! s& ev5 ) a good s$im5t lay] on ! surface1 & ! effici5cy ( deep filt]s is great] ?an t ( %all[ ones4 ,lay]s ( f9] mat]ials1 z f9e s& or loam1 9 ! l[] "p ( a filt]1 :i* w\ld o!rwise give increas$ effici5cy )\t increas+ ! op]at+ exp5ses1 _c be us$4 ,_! pres5ce inv>iably gives rise soon] or lat] to sub-surface clogg+ at ! po9t ( junction ) ! co>s] s&1 z has be5 f\nd by repeat$ te/s at ,lawr5ce z well z 9 "s ( ! ,dut* filt]s :]e su* lay]s 7 tri$2 & z !re is no object 9 putt+ a co>s] s& "u a f9]1 ! filt] s& is be/ all ( ! same size & quality f top to bottom4 ,,und]dra9+4 ,! und]dra9s ( a filt] are simply useful = collect+ ! filt]$ wat]2 !y play no "p 9 ! purification4 ,"o ( ! fir/ requirem5ts ( successful filtration is t ! rate ( filtration %all be practically ! same 9 all p>ts ( ! filt]4 ,?is is mo/ difficult to secure :5 ! filt] has j be5 clean$ & ! friction ( ! s& lay] is at a m9imum4 ,if ! friction ( ! wat] 9 ent]+ & pass+ ?r\gh ! und]dra9s is consid]able1 ! m remote p>ts ( ! filt]s w "w "u less pressure1 & w ?us d less ?an _! %>e ( ! "w1 :ile ! p>ts ne> ! outlet w be ov]tax$1 & filt]+ at too high rates w yield poor efflu5ts4 ,to avoid ?is condition ! und]dra9s mu/ h su* a capacity t _! frictional resi/ance w be only a small fraction ( ! friction 9 ! s& itself j aft] clean+4 ,,gravel ,,lay]s4 ,! e>ly filt]s conta9$ an enorm\s quantity ( gravel1 b ! quantity has be5 /eadily r$uc$ 9 successive plants4 ,?us 9 #ahff ,kirkwood1 z a result ( 8 obs]vations1 recomm5d$ ! use ( a lay] f\r feet ?ick1 & 9 addition a foot ( co>se s&1 :ile at ! pres5t "t new filt]s r>ely h m ?an two feet ( gravel4 ,ev5 ?is quantity seems q sup]flu\s1 :5 calculations ( its frictional resi/ance are made4 ,?us a lay] ( gravel ) an effective size ( #bj mm4#e 7:i* is mu* f9] ?an t g5]ally employ$7 only #f in*es ?ick w c>ry ! efflu5t f a filt] work+ at a rate ( #b4eg million gallons p] acre daily = a di/ance ( #h feet 7t is1 ) und]dra9s #af feet ap>t71 ) a loss ( head ( only #j4jja foot1 & = long] di/ances tile dra9s are *eap] ?an gravel4 ,to prev5t ! s& f s9k+ into ! co>se gravel1 int]m$iate sizes ( gravel mu/ be plac$ betwe51 ea* grade be+ co>se en\gh s t !re is no possibility ( its s9k+ into ! lay] bel[4 ,! necess>y ?ickness ( ^! int]m$iate lay]s is v small1 ! pr9cipal po9t be+ to h a lay] ( ea* grade at e po9t4 ,?us on ! #f in*es ( #bj mm4 gravel m5tion$ above1 ?ree lay]s ( two in*es ea*1 ( #h & #c mm4 gravel & co>se s&1 ) a total height ( six in*es1 or o!r correspond+ & conv5i5t dep?s & sizes1 w\ld1 if c>efully plac$1 z effectually prev5t ! s9k+ ( ! filt] s& into ! co>se gravel z ! mu* ?ick] lay]s us$ 9 ! old] plants4 ,! gravel ar\nd ! dra9s %\ld receive special att5tion4 ,l>g] /ones c be "h us$ ) advantage1 tak+ c>e t adequate spaces are left = ! entrance ( ! wat] into ! dra9s at a l[ velocity1 & to make ev]y?+ s solid 9 ?is neighborhood t !re w be no *ance = ! /ones to settle :i* might all[ ! s& to rea* ! dra9s4 ,illu/ration3 ,,recon/ruct+ ,,! ,,und]dra9age ,,sy/em ,,( ,a ,,filt] ,,aft] #be ,,ye>s ,,( ,,use1 ,,brem54 ,illu/ration3 ,,plac+ ,,s& ,,9 ,a ,,filt]1 ,,*oisy ,,le ,,roi 7,,p>is74 ,to face page #cf4 ,at ! ,lawr5ce filt]1 at ,knigsb]g 9 ,prussia1 at ,am/]dam & o!r places1 ! quantity ( gravel is r$uc$ by putt+ ! dra9s 9 tr5*es1 s t ! gravel is r$uc$ f a maximum ?ickness at ! dra9 to no?+ half way betwe5 dra9s4 ,! economy ( ! arrangem5t1 h[ev]1 z f> z friction is conc]n$ is n s great z w\ld appe> at fir/ sight1 & ! co/ ( ! bottom may be increas$2 b on ! o!r h& x gives a great] dep? ( gravel = cov]+ ! dra9s ) a small total am\nt ( gravel4 ,z ev5 a v small p]c5tage ( f9e mat]ial is capable ( gett+ 9 ! n>r[ places & r$uc+ ! c>ry+ p[] ( ! gravel1 x is important t all su* matt]s %\ld be c>efully remov$ by wa%+ be=e putt+ ! gravel 9 place4 ,9 ,engl& & ,g]many gravel is commonly scre5$ = use 9 revolv+ cyl9d]s ( wire-clo? ( ! desir$ sizes1 on :i* wat] is freely play$ f num]\s jets1 ?us secur+ p]fectly clean gravel4 ,9 gett+ gravel = ! ,lawr5ce filt]1 an app>atus 0 us$1 9 :i* advantage 0 tak5 ( ! natural slope ( ! gravel bank to d ! "w1 & ! use ( p[] 0 avoid$4 ,! respective grades ( gravel obta9$ 7 ev5 9 size1 & reasonably free f f9e mat]ial1 b x 0 deem$ be/ to wa% !m ) a hose be=e putt+ !m 9 ! filt]4 ,to calculate ! frictional resi/ance ( wat] 9 pass+ gravel1 we may assume t = ! v l[ velocities :i* are actually f\nd 9 filt]s ! quantity ( wat] pass+ v>ies directly ) ! head1 :i* = ^! velocities is sub/antially correct1 al?\gh x w\ld n be true = high] rates1 especially ) ! co>s] gravels4#f ,9 ! case ( p>allel und]dra9s ! friction f ! middle po9t betwe5 dra9s to ! dra9s may be calculat$ by ! =mula3 ,total head 7#a_/b77,rate ( filtration 7#a_/b di/ance betwe5 dra9s7#b7_/7;,av]age dep? ( gravel dis*>ge coeffici5t74 ,! dis*>ge coeffici5t = any gravel is #ajjj times ! quantity ( wat] :i* w pass :5 h_/l is #a_/ajjj express$ 9 million gallons p] acre daily4 ,! approximate values ( ?is coeffici5t = diff]5t-siz$ gravels are z foll[s3 ,,values ,,( ,,dis*>ge ,,coeffici5t4 ,= gravel ) effective size #e mm c #bc1jjj ,= gravel ) effective size#aj mm c #fe1jjj ,= gravel ) effective size#ae mm c #aaj1jjj ,= gravel ) effective size#bj mm c #afj1jjj ,= gravel ) effective size#be mm c #bcj1jjj ,= gravel ) effective size#cj mm c #cjj1jjj ,= gravel ) effective size#ce mm c #cij1jjj ,= gravel ) effective size#dj mm c #dhj1jjj ,example3 ,:at is ! loss ( head 9 ! gravel at a rate ( filtration ( #b million gallons p] acre daily1 ) und]dra9s #bj feet ap>t1 :]e ! support+ gravel has an effective size ( #ce millimet]s1 & is uni=mly #a ft4 deep8 ,total head 7#a_/b77b #ajb7_/7a #cij1jjj7 4#jjjbef ft4 ,! total friction w\ld be ! same ) ! same av]age dep? ( gravel :e!r x 0 uni=mly #a foot deep1 or decreas+ f #a4e at ! dra9s to #j4e 9 ! middle1 or f #b4j to #j4 ,! rev]se case ) ! gravel lay] ?ick] 9 ! middle ?an at ! dra9s does n occur & ne$ n be discuss$4 ,! dep? ( gravel likely to be adopt$ z a result ( ?is calculation1 :5 ! dra9s are n too f> ap>t1 w be mu* less ?an t actually us$ 9 mo/ ,european works1 b z ! two feet or m !re employ$ are1 ,i believe1 simply ! result ( speculation1 !re is no reason = foll[+ ! prec$5t :]e calculations %[ t a small] quantity is adequate4 ,! reason = recomm5d+ a ?9 l[] lay] ( co>se gravel1 :i* alone is assum$ to provide = ! lat]al movem5t ( ! wat]1 is t if m ?an ab\t six in*es ( gravel is requir$ to give a satisfactory resi/ance1 x w almo/ always be *eap] to use m dra9s in/ead ( m gravel2 & ! reason = recomm5d+ ?9n] upp] lay]s = prev5t+ ! s& f settl+ into ! co>se gravel is t no failures ( ?is portion ( filt]s are on record1 & 9 ! few in/ances :]e really ?9 lay]s h be5 us$ ! results h be5 entirely satisfactory4 ,9 ,knigsb]g filt]s 7 built by ,frhl+1#g 9 :i* ! s& 0 support$ by five lay]s ( gravel ( increas+ sizes1 respectively #a4b1 #a4b1 #a4f1 #b4j1 #c4b1 or1 toge!r1 #i4b in*es ?ick1 bel[ :i* !re 7 an av]age ( five in*es ( co>se gravel4 ,^! 7 exam9$ aft] eight ye>s ( op]ation & f\nd to be 9 p]fect ord]4 ,at ! ,lawr5ce ,exp]im5t ,/ation filt]s h be5 repeat$ly con/ruct$ ) a total dep? ( support+ gravel lay]s n exce$+ six in*es1 & among ! scores ( su* filt]s !re has n be5 a s+le failure1 & s f> z !y h be5 dug up !re has nev] be5 f\nd to h be5 any movem5t :atev] ( ! s& into ! gravel4 ,! ,lawr5ce city filt]1 built ) correspond+ lay]s1 has %[n no signs ( be+ inadequately support$4 ,9 arrang+ ! ,lawr5ce gravel lay]s c>e has always be5 tak5 t no mat]ial %\ld re/ on ano!r mat]ial m ?an ?ree or f\r times z co>se z itself1 & t ea* lay] %\ld be complete at e po9t1 s t by no possibility c\ld two lay]s ( great] diff]5ce 9 size come toge!r4 ,& x is believ$ t if ?is is c>efully att5d$ to1 no tr\ble ne$ be anticipat$1 h[ev] ?9 ! s+le lay]s may be4 ,,und]dra9s4 ,! mo/ common arrangem5t1 9 o!r ?an v small filt]s1 is to h a ma9 dra9 ?r\gh ! middle ( ! filt]1 ) lat]al dra9s at regul> int]vals f x to ! sides4 ,! sides ( ! ma9 dra9 are ( brick1 laid ) op5 jo9ts to admit wat] freely1 & ! top is usually cov]$ ) /one slabs4 ,! lat]al dra9s may be built 9 ! same way1 b tile dra9s are also us$ & are *eap]4 ,c>e mu/ be tak5 ) ! latt] t ample op5+s are left = ! admission ( wat] at v l[ velocities4 ,x is consid]$ desirable to h ^! dra9s g no high] ?an ! top ( ! co>se/ gravel2 & ?is w (t5 control ! dep? ( gravel us$4 ,if !y g high]1 ! top mu/ be made tight to prev5t ! entrance ( ! f9e gravels or s&4 ,sometimes !y are sunk 9 "p or :olly 7especially ! ma9 dra97 bel[ ! floor ( ! filt]4 ,) gravel plac$ 9 waves1 t is1 ?ick] ov] ! dra9s ?an else:]e1 z m5tion$ above1 ! dra9s are cov]$ m easily ?an ) an entirely horizontal arrangem5t4 ,:5 ?is is done1 ! floor ( ! filt] is tr5*$ to meet ! v>y+ ?ickness ( gravel1 s t ! top ( ! latt] is level1 & ! s& has a uni=m ?ickness4 ,_m filt]s 7,lambe?1 ,brunswick1 etc47 are built ) a d\ble bottom ( brick1 ! upp] lay] ( :i*1 ) op5 jo9ts1 supports ! gravel & s&1 & is itself support$ by num]\s small ar*es or o!r arrangem5ts ( brick1 :i* s]ve to c>ry ! wat] to ! outlet )\t o!r dra9s4 ,?is arrangem5t all[s ! use ( a m9imum quantity ( gravel1 b is und\bt$ly m exp5sive ?an ! usual =m1 ) only ! necess>y quantity ( gravel2 & ,i am unable to f9d t x has any correspond+ advantages4 ,! frictional resi/ance ( und]dra9s requires to be c>efully calculat$2 & 9 do+ ?is q diff]5t /&>ds mu/ be foll[$ f ^? usually employ$ 9 det]m9+ ! sizes ( wat]-pipes1 z a total frictional resi/ance ( only a few hundr$?s ( a foot1 includ+ ! velocity head1 may cause s]i\s irregul>ities 9 ! rate ( filtration 9 diff]5t p>ts ( ! filt]4 ,! sizes ( ! und]dra9s diff] v widely 9 proportion to ! sizes ( ! filt]s 9 ,european works1 "s ( !m be+ excessively l>ge1 :ile 9 o!r cases !y are s small z to sugge/ a d\bt z to _! all[+ uni=m rates ( filtration1 especially j aft] clean+4 ,i w\ld sugge/ ! foll[+ rules z reasonably sure to lead to satisfactory results )\t mak+ an altoge!r too lavi% provision3 ,9 ! abs5ce ( a def9ite det]m9ation to run filt]s at "s o!r rate1 calculate ! dra9s = ! ,g]man /&>d rate ( a daily column ( #b4dj met]s1 equal to #b4eg million gallons p] acre daily4 ,?is w insure satisfactory "w at all l[] rates1 & no difficulty on acc\nt ( ! capacity ( ! und]dra9s ne$ be !n anticipat$ if ! rate is some:at exce$$4 ,! area = a c]ta9 di/ance f ! ma9 dra9 dep5d+ ^u ! gravel may be calculat$ z dra9+ directly into x1 provid$ !re are suitable op5+s1 & ! re/ ( ! area is suppos$ to dra9 to ! ne>e/ lat]al dra94 ,9 case ! lat]als are r\nd-tile dra9s ,i w\ld sugge/ ! foll[+ limits to ! areas :i* !y %\ld be all[$ to dra93 ,diamet] ( ,dra94 ,to ,dra9 an ,area n ,correspond+ ,velocity ( ,exce$+ ,wat] 9 ,dra94 #d in*es #bij squ>e feet4 #j4cj foot4 #f in*es #gej squ>e feet4 #j4ce foot4 #h in*es #aecj squ>e feet4 #j4dj foot4 #aj in*es #bghj squ>e feet4 #j4df foot4 #ab in*es #ddjj squ>e feet4 #j4ea foot4 ,& = l>g] dra9s1 includ+ ! ma9 dra9s1 _! cross-sections at any po9t %\ld be at lea/ #a_/fjjj ( ! area dra9$1 giv+ a velocity ( #j4ee foot p] second ) ! rate ( filtration m5tion$ above4 ,! total friction ( ! und]dra9s f ! mo/ remote po9ts to ! outlet w be friction 9 ! gravel1 plus friction 9 ! lat]al dra9s1 plus ! friction 9 ma9 dra91 plus ! velocity head4 ,illu/ration3 ,,fig4 #d4--,,plan ,,( ,,"o ,,( ,,! ,,hamburg ,,filt]s1 ,,%[+ ,,frictional ,,resi/ance ,,( ,,! ,,und]dra9s4 ,i h calculat$ 9 ?is way ! friction ( "o ( ! ,hamburg filt]s = ! rate ( #a1fjj1jjj gallons p] acre daily at :i* x is us$4 ,! friction 0 calculat$ = ea* section ( ! dra9s sep>ately1 s t ! friction f int]m$iate po9ts 0 also kn[n4 ,kutt]'s =mula 0 us$ ?r\gh\t ) n #j4jac4 ,on ! accompany+ plan ( ! filt] ,i h drawn ! l9es ( equal frictional resi/ance f ! junction ( ! ma9 dra9 ) ! la/ lat]als4 ,my in=mation 0 incomplete 9 reg>d to "o or two po9ts1 s t ! calculation may n be /rictly accurate1 b x is ne>ly s & w illu/rate ! pr9ciples involv$4 ,illu/ration3 ,,con/ruct+ ,,! ,,und]dra9age ,,sy/em ,,( ,a ,,filt]1 ,,hamburg4 ,to face page #db4 ,! extreme friction ( ! und]dra9s is #aa millimet]s #j4jcf foot4 ,! frictional resi/ance ( ! s& #ci in*es ?ick1 effective size #j4cb mm4 & rate #a4fj million gallons p] acre daily1 :5 absolutely free f clogg+1 is by ! =mula1 page #ba1 #aemm41 or 4#jdij foot1 :5 ! temp]ature is #ej4 ,practically !re is "s matt] deposit$ ^u ! surface ( ! s& be=e filtration />ts1 & fur!r1 aft] ! fir/ scrap+1 !re is "s slight clogg+ 9 ! s& bel[ ! lay] remov$ by scrap+4 ,we c ?us safely take ! m9imum frictional resi/ance ( ! s& includ+ ! surface lay] at 4#jg foot4 ,! av]age friction ( ! und]dra9s = all po9ts is ab\t 4#jbc foot & ! friction at />t+ w be 4#jg 4#jbc 4#jic foot 7includ+ ! friction 9 ! la/ section to ! efflu5t well :]e ! head is measur$1 4#ajj foot1 b ! friction beyond ! la/ lat]al does n affect ! uni=mity ( filtration74 ,! actual head on ! s& close to ! outlet w be 4#jic & ! rate ( filtration 4#jic_/4jgj #a4fj #b4ab4 ,! actual head at ! mo/ remote po9t w be 4#jic - 4#jcf 4#jeg1 & ! rate ( filtration w !re be 4#jeg_/4jgj #afj #a4cj million gallons p] acre daily4 ,! extreme rates ( filtration are ?us #b4ab & #a4cj1 in/ead ( ! av]age rate ( #a4fj4 ,z c be se5 f ! diagram1 only v small areas "w at ^! extreme rates1 ! great bulk ( ! area work+ at rates mu* ne>] ! av]age4 ,actually ! filt] is />t$ at a rate bel[ #a4fj1 & ! ne>e/ portion nev] filt]s s rapidly z #b4ab1 = :5 ! rate is increas$ to ! /&>d1 ! s& has become s f> clogg$ t ! loss ( head is m ?an ! 4#jg foot assum$1 & ! diff]5ces 9 ! rates are correspond+ly r$uc$4 ,tak+ ?is into acc\nt1 x w\ld n seem t ! irregul>ities 9 ! rate ( filtration are suffici5t to affect s]i\sly ! action ( ! filt]4 ,!y c\ld evid5tly h be5 l>gely r$uc$ by mod]ately increas+ ! sizes ( ! l[] ends ( ! und]dra9s1 :]e mo/ ( ! friction occurs ) ! high velocities 7up to 4#ig foot7 :i* !re result4 ,! und]dra9s ( ! ,w>saw filt]s 7 design$ by ,l9dley to h a maximum loss ( head ( only 4#jafd foot :5 filt]+ at a rate ( #b4eg1 :i* gives a v>iation ( only #aj p] c5t 9 ! rates ) ! m9imum loss ( head ( 4#afi foot 9 ! entire filt] assum$ by him4 ,! und]dra9s ( ! ,b]l9 filt]s1 accord+ to my calculations1 h 4#jbj to 4#jcj foot friction1 ( :i* an unusually l>ge proportion is 9 ! gravel1 ow+ to ! excessive di/ances1 9 "s cases ov] #hj feet1 :i* ! gravel is requir$ to c>ry ! wat]4 ,9 ?is case1 us+ less or f9] gravel w\ld obvi\sly h be5 fatal1 b ! friction z well z ! exp5se ( con/ruction w\ld be mu* r$uc$ by us+ m dra9s & less gravel4 ,! und]dra9s might appropriately be made slightly small]1 ) a deep lay] ( f9e s&1 ?an "u opposite conditions1 z 9 ?is case ! increas$ friction 9 ! dra9s w\ld be no great] 9 proportion to ! increas$ friction 9 ! s& itself4 ,! und]dra9s ( a majority ( ,european filt]s h wat]-tight pipes connect+ ) !m at int]vals1 & go+ up ?r\gh ! s& & above ! wat]1 :]e !y are op5 to ! air4 ,^! pipes 7 int5d$ to v5tilate ! und]dra9s & all[ ! escape ( air :5 ! filt] is fill$ ) wat] introduc$ f bel[4 ,x may be said1 h[ev]1 t 9 case ! dra9s are surr\nd$ by gravel & !re is an opportunity = ! air to pass f ! top ( ! dra9 into ! gravel1 x w s escape )\t special provision be+ made = x1 & g up ?r\gh ! s& ) ! mu* l>g] quantity ( air 9 ! upp] "p ( ! gravel :i* is incapable ( be+ remov$ by pipes connect+ ) ! dra9s4 ,^! v5tilator pipes :]e !y are us$ are a s\rce ( mu* tr\ble1 z unfilt]$ wat] is apt to run d[n ?r\gh cracks 9 ! s& beside !m1 &1 "u bad managem5t1 unfilt]$ wat] may ev5 g d[n ?r\gh ! pipes !mselves4 ,i am unable to f9d t !y are necess>y1 except ) und]dra9s s con/ruct$ t !re is no o!r *ance = ! escape ( air f ! tops ( !m1 or t !y s]ve any useful purpose1 :ile !re are positive objections to _! use4 ,9 "s ( ! new] filt]s !y h be5 omitt$ ) satisfactory results4 ,,dep? ,,( ,,wat] ,,on ,,! ,,filt]s4 ,9 ! old] works ) b crude appliances = regulat+ ! rate ( filtration & admission ( raw wat]1 a consid]able dep? ( wat] 0 necess>y ^u ! filt] to balance irregul>ities 9 ! rates ( filtration2 ! filt] 0 made to be1 to a c]ta9 ext5t1 its own /orage res]voir4 ,:51 h[ev]1 appliances ( ! "* to be describ$ 9 ,*apt] ,,iv are us$ = ! regulation ( ! incom+ wat]1 & ) a /eady rate ( filtration1 ?is provision becomes q sup]flu\s4 ,) op5 filt]s a dep? ( wat] 9 excess ( ! ?ickness ( any ice likely to be =m$ is requir$ to prev5t di/urbance or freez+ ( ! s& 9 w9t]4 ,x is also frequ5tly urg$ t ) a deep wat] lay] on ! filt] ! wat] does n become s mu* heat$ 9 summ]1 b ?is po9t is n believ$ to be well tak51 = 9 any giv5 case ! total am\nt ( heat com+ f ! sun to a giv5 area is con/ant1 & ! quantity ( wat] heat$ 9 ! :ole day--t is1 ! am\nt filt]$--is con/ant1 & v>iations 9 ! quantity expos$ at "o "t w n affect ! av]age result+ increase 9 temp]ature4 ,if ! same wat] rema9$ ^u ! filt] )\t *ange x w\ld ( c\rse be true t a ?9 lay] w\ld be heat$ m ?an a deep "o1 b ?is is n ! case4 ,x is also sometimes recomm5d$ t ! dep? ( wat] %\ld be suffici5t to =m a s$im5t lay] be=e filtration />ts1 b ?is po9t w\ld seem to be ( d\btful value1 especially :]e ! filt] is n all[$ to /& a consid]able "t ) ! raw wat] ^u x be=e />t+ filtration4 ,x is also cu/om>y to h a dep? ( wat] on ! filt] 9 excess ( ! maximum loss ( head1 s t !re c nev] be a suction 9 ! s& j bel[ ! s$im5t lay]4 ,x may be said 9 reg>d to ?is1 h[ev]1 t a suction bel[ is j z effective 9 mak+ ! wat] pass ! s& z an equal head above4 ,at ! ,lawr5ce ,exp]im5t ,/ation filt]s h be5 repeat$ly us$ ) a wat] dep? ( only f #f to #ab in*es1 ) losses ( head rea*+ #f feet1 )\t ! slighte/ inconv5i5ce4 ,! suction only comm5ces to exi/ z ! increas+ head becomes great] ?an ! dep? ( wat]1 & !re is no way 9 :i* air f outside c get 9 to relieve x4 ,9 ^! exp]im5tal filt]s 9 w9t]1 :5 ! wat] is completely saturat$ ) air1 a small "p ( ! air comes out ( ! wat] j z x passes ! s$im5t lay] & gets into r$uc$ pressure1 & ?is air prev5ts ! satisfactory op]ation ( ! filt]s4 ,b ?is is believ$ to be due m to ! w>m+ & consequ5t sup]saturation ( ! wat] 9 ! comp>atively w>m places 9 :i* ! filt]s /& ?an to ! lack ( pressure1 & z n ! slighte/ tr\ble is exp]i5c$ at o!r seasons ( ! ye>1 x may be que/ion$ :e!r !re w\ld be any disadvantage at any "t 9 a correspond+ arrangem5t on a l>ge scale :]e w>m+ c\ld n occur4 ,! dep?s ( wat] actually us$ 9 ,european filt]s ) ! full dep? ( s& are usually f #cf to #eb in*es4 ,9 only a v few unimportant cases is less ?an ! above us$1 & only a few ( ! old] works use a great] dep?1 :i* is n foll[$ 9 any ( ! mod]n plants4 ,z ! s& becomes r$uc$ 9 ?ickness by scrap+1 ! dep? ( wat] is correspond+ly increas$ above ! figures giv5 until ! s& is replac$4 ,! dep? ( wat] on ! ,g]man cov]$ filt]s is q z great z ^u correspond+ op5 filt]s4 ,?us ! ,b]l9 cov]$ filt]s h #ea1 :ile ! new op5 filt]s at ,hamburg h only #dc in*es4 ,,*apt] ,,iv4 ,,rate ,,( ,,filtration ,,& ,,loss ,,( ,,head4 ,! rate ( filtration recomm5d$ & us$ has be5 gradually r$uc$ dur+ ! pa/ ?irty ye>s4 ,9 #ahff ,kirkwood f\nd t #ab v]tical feet p] day1 or #c4ij million gallons p] acre daily1 0 recomm5d$ by ! be/ eng9e]s1 & 0 commonly foll[$ z an av]age rate4 ,9 #ahfh ! ,london filt]s av]ag$ a yield ( #b4ah million gallons#h p] acre daily1 includ+ areas tempor>ily out ( use1 :ile 9 #ahhe ! quantity _h be5 r$uc$ to #a4fa4 ,s9ce t "t ! rate has app>5tly be5 slightly increas$4 ,! ,b]l9 filt]s at ,/ralau con/ruct$ 9 #ahgd 7 built to filt] at a rate ( #c4ba million gallons p] acre daily4 ,! fir/ filt]s at ,tegel 7 built = a correspond+ rate1 b h be5 us$ only at a rate ( #b4eg1 :ile ! m rec5t filt]s 7 calculat$ = ?is rate4 ,! new ,hamburg filt]s1 #ahib-c1 7 only int5d$ to filt] at a rate ( #a4fj million gallons p] acre daily4 ,^! 9 ea* case 7except ! ,london figures7 are ! /&>d rates = ! filt]-b$s actually 9 s]vice4 ,9 practice ! area ( filt]s is l>g] ?an is calculat$ f ^! figures1 z filt]s mu/ be built to meet maximum in/ead ( av]age daily consumptions1 & a portion ( ! filt]+ area usually e/imat$ at f #e to #ae p] c5t1 b 9 extreme cases rea*+ #ej p] c5t1 is usually be+ clean$1 & s is = ! "t out ( s]vice4 ,9 "s works also ! rate ( filtration on />t+ a filt] is kept l[] ?an ! /&>d rate = a day or two1 or ! fir/ portion ( ! efflu5t1 suppos$ to be ( inf]ior quality1 is wa/$1 ! am\nt s lo/ rea*+ 9 an extreme case #i to #ad p] c5t ( ! total quantity ( wat] filt]$4#i ,9 _m ( ! old] works also1 !re is n /orage capacity en\gh = filt]$ wat] to balance ! h\rly fluctuations 9 consumption1 & ! filt]s mu/ be l>ge en\gh to meet ! maximum h\rly z well z ! maximum daily requirem5ts4 ,= ^! reasons ! actual quantity ( wat] filt]$ 9 a ye> is only f #ej to #ge p] c5t ( :at w\ld be ! case if ! entire area ( ! filt]s work$ con/antly at ! full rate4 ,a /atem5t ( ! actual yields ( a numb] ( filt] plants is giv5 9 ,app5dix ,,iv4 ,! figures = ! av]age annual yields c be tak5 z q reliable4 ,! figures giv5 = rate1 9 _m cases1 h little value1 ow+ to ! diff]5t ways 9 :i* !y are calculat$ at diff]5t places4 ,9 addition mo/ ( ! old works h no adequate means ( det]m9+ :at ! rate at any p>ticul> "t & = a s+le filt] really is1 & /atem5ts ( av]age rates h only limit$ value4 ,! filt]s at ,hamburg are n all[$ to filt] fa/] ?an #a4fj or ^? at ,b]l9 fa/] ?an #b4eg million gallons p] acre daily1 & adequate means are provid$ to secure ?is condition4 ,o!r ,g]man works aim to keep )9 ! latt] limit4 ,beyond ?is1 unless detail$ in=mation 9 reg>d to me?ods is pres5t$1 /atem5ts ( rate mu/ be tak5 ) "s all[ance4 ,,effect ,,( ,,rate ,,^u ,,co/ ,,( ,,filtration4 ,! size ( ! filt]s requir$1 & consequ5tly ! fir/ co/1 dep5ds ^u ! rate ( filtration1 b ) increas+ rates ! co/ is n r$uc$ 9 ! same proportion z ! increase 9 rate1 s9ce ! all[ance = area out ( use is s5sibly ! same = high & l[ rates1 & 9 addition ! op]at+ exp5ses dep5d ^u ! quantity filt]$ & n ^u ! filt]+ area4 ,?us1 to supply #aj million gallons at a maximum rate ( #b million gallons p] acre daily we %\ld require #aj #b #e acres #a acre res]ve = clean+ #f acres1 :ile ) a rate twice z great1 & ) ! same res]ve 7s9ce ! same am\nt ( clean+ mu/ be done1 z w be %[n bel[71 we %\ld require #aj #d #a #c4e acres1 or #eh p] c5t ( ! area requir$ = ! l[] rate4 ,?us beyond a c]ta9 po9t increas+ ! rate does n effect a correspond+ r$uction 9 ! fir/ co/4 ,! op]at+ co/ = ! same quantity ( wat] filt]$ does n appe> to be appreciably affect$ by ! rate4 ,x is obvi\s t at high rates filt]s w became clogg$ m rapidly1 & w s require to be scrap$ (t5] ?an at l[ rates1 & x might naturally be suppos$ t ! clogg+ w\ld increase m rapidly ?an ! rates1 b ?is does n seem to be ! case4 ,at ! ,lawr5ce ,exp]im5t ,/ation1 "u /rictly p>allel conditions & ) id5tically ! same wat]1 filt]s runn+ at v>i\s rates became clogg$ ) a rapidity directly proportional to ! rates1 s t ! quantities ( wat] filt]$ betwe5 scrap+s "u any giv5 conditions are ! same :e!r ! rate is high or l[4 ,! /ati/ics be>+ ^u ?is po9t are int]e/+1 if n entirely conclusive4 ,!re 7 elev5 places 9 ,g]many filt]+ riv] wat]s1 f :i* /ati/ics 7 available = ! ye> #ahia-ib4 ,( ^! !re 7 f\r places ) high rates1 ,lbeck1 ,/ett91 ,/uttg>t1 & ,magdeburg1 yield+ #c4gj million gallons p] acre daily1 :i* filt]$ on an av]age #ei million gallons p] acre betwe5 scrap+s4 ,?ree o!r places1 ,breslau1 ,altona1 & ,frankfurt1 yield+ #a4he1 pass$ on an av]age #ee million gallons p] acre betwe5 scrap+s1 & f\r o!r places1 ,brem51 ,knigsb]g1 ,brunswick & ,pos51 yield+ #a4cd million gallons p] acre daily1 pass$ only #dj million gallons p] acre betwe5 scrap+s4 ,! works filt]+ at ! highe/ rates ?us filt]$ m wat] 9 proportion to ! s& clogg$ ?an did ^? filt]+ m sl[ly1 b ,i _c ?9k t ?is 0 ! result ( ! rate4 ,x is m likely t "s ( ! places h cle>] wat]s ?an o!rs1 & t ?is bo? all[s ! high] rate & causes less clogg+ ?an ! m turbid wat]s4 ,,effect ,,( ,,rate ,,^u ,,effici5cy ,,( ,,filtration4 ,! effect ( ! rate ( filtration ^u ! quality ( ! efflu5t has be5 repeat$ly inve/igat$4 ,! effici5cy almo/ uni=mly decreases rapidly ) increas+ rate4 ,frnkel & ,piefke#aj fir/ f\nd t ) ! high rates ! numb] ( bact]ia pass+ "s exp]im5tal filt]s 0 greatly increas$4 ,piefke#aa aft]w>d repeat$ ^! exp]im5ts1 elim9at+ "s ( ! features ( ! fir/ s]ies to :i* objection 0 made1 & confirm$ ! fir/ results4 ,! results 7 s m>k$ t ,piefke 0 l$ to recomm5d ! extremely l[ limit ( #a4bh million gallons p] acre daily z ! safe maximum rate ( filtration1 b he has s9ce repeat$ly us$ #b4eg million gallons4 ,kmmel1#ab on ! o!r h&1 9 a some:at limit$ s]ies ( exp]im5ts1 0 unable to f9d any m>k$ connection betwe5 ! rate & ! effici5cy1 a rate ( #b4eg giv+ slightly bett] results ?an rates ( ei!r #a4bh or #e4ad4 ,! admirably execut$ exp]im5ts made at ,zri* 9 #ahhf-h ^u ?is po9t1 :i* gave ?r\gh\t negative results1 h b little value 9 ?is connection1 ow+ to ! extremely l[ numb] ( bact]ia 9 ! orig9al wat]4 ,at ,lawr5ce 9 #ahib ! foll[+ p]c5tages ( bact]ia 7,b4 prodigiosus7 pass$ at ! respective rates3 ---------------------------------------- -------------------------- ,no4 ( ,dep?4 ,effective ,rate4 ,millions gallons p] acre daily4 ,filt]4 ,size ( ----------------------------------- ,s&4 #j4e #a4j #a4e #b4j #c4j ---------------------------------------- ---------------------- #cc;,a #fj #j4ad #j4jjb #j4jdj #cd;,a #fj #j4ji #j4jja #j4jje #j4jbj #cf;,a #fj #j4bj #j4jej #j4jej #cg #fj #j4bj #j4jaj #j4acj #ch #bd #j4bj #j4jah #j4adj #j4aaj #j4caj #ci #ab #j4bj #j4jad #j4jgj #j4jhj #j4ebj #dj #ab #j4bj #j4jgj #j4jij #db #ab #j4bj #j4jaf #j4aej #j4eej ---------------------------------------- ---------------------- ,av]age #j4jaj #j4jdh #j4jfg #j4jhh #j4cef ---------------------------------------- ------------------------ ,^! results %[ a v m>k$ decrease 9 effici5cy ) increas+ rates1 ! numb] ( bact]ia pass+ increas+ 9 g5]al z rapidly z ! squ>e ( ! rate4 ,! #ahic results also %[$ decreas$ effici5cy ) high rates1 b ! range 9 ! rates "u comp>able conditions 0 less ?an 9 #ahib1 & ! bact]ial diff]5ces 7 less %>ply m>k$4 ,:ile ! av]age results at ,lawr5ce1 z well z mo/ ( ! ,european exp]im5ts1 %[ greatly decreas$ effici5cy ) high rates1 !re are _m s+le cases1 p>ticul>ly ) deep lay]s ( n too co>se s&1 :]e1 z 9 ,kmmel's exp]im5ts1 !re seems to be little connection betwe5 ! rate & effici5cy4 ,an explanation ( ^! app>5tly abnormal results w be giv5 9 ,*apt] ,,vi4 ,x is commonly /at$#ac t e wat] has its own special rate ( filtration1 :i* mu/ be det]m9$ by local exp]im5ts1 & t ?is rate may v>y widely 9 diff]5t cases4 ,?us x is possible t ! rate ( #a4fj adopt$ at ,hamburg = ! turbid ,elbe wat]1 ! rate ( #b4eg us$ at ,b]l91 & ab\t ! same at ,london = mu* cle>] riv]-wat]s1 & ! rate ( #g4ej us$ at ,zri* = ! almo/ p]fectly cle> lake-wat] are 9 ea* case ! mo/ suitable = ! respective wat]s4 ,9 o!r cases h[ev]1 :]e rates mu* above #b4eg are us$ = riv]-wat]s1 z at ,lbeck & ,/ett91 !re is a decid$ op9ion t ^! rates are excessive1 & 9 ^! in/ances /eps are n[ be+ tak5 to s increase ! filt]+ areas z to br+ ! rates )9 ! limit ( #b4eg million gallons p] acre daily4 ,f ! tr5d ( ,european practice x w\ld seem t = ,am]ican riv]-wat]s ! rate ( filtration %\ld n exce$ #b4eg 9 place ( ! #c4ij million gallons p] acre daily recomm5d$ by ,kirkwood1 or ev5 t a some:at l[] rate might be desirable 9 "s cases4 ,( c\rse1 9 addition to ! area necess>y to give ?is rate1 a res]ve = fluctuat+ rates & = clean+ %\ld be provid$1 r$uc+ ! av]age yield to #b4jj1 #a4ej1 or ev5 less4 ,9 ! case ( wat] f cle> lakes1 ponds1 or /orage res]voirs1 especially :5 !y are n subject to excessive sewage pollution or to /rong alg gr[?s1 x w\ld seem t rates some:at & p]haps 9 "s cases v mu* high] 7z at ,zri*7 c\ld be satisfactorily us$4 ,,! ,,loss ,,( ,,head4 ,! loss ( head is ! diff]5ce betwe5 ! heads ( ! wat]s above & bel[ ! s& lay]1 & repres5ts ! frictional resi/ance ( t lay]4 ,:5 a filt] is q free f clogg+ ?is frictional resi/ance is small1 b gradually increases ) ! deposit ( a s$im5t lay] f ! wat] filt]$ until x becomes s great t ! clogg+ mu/ be remov$ by scrap+ be=e ! process c be cont9u$4 ,aft] scrap+ ! loss ( head is r$uc$ to1 or ne>ly to1 its orig9al am\nt4 ,) any giv5 am\nt ( clogg+ ! loss ( head is directly proportional to ! rate ( filtration2 t is1 if a filt] p>tially clogg$1 filt]+ at a rate ( #a4j1 has a frictional resi/ance ( #j4e ft41 ! resi/ance w be d\bl$ by increas+ ! rate to #b4jj million gallons p] acre daily1 provid$ no di/urbance ( ! s$im5t lay] is all[$4 ,?is law = ! frictional resi/ance ( wat] 9 s& alone also applies to ! s$im5t lay]1 z ,i h f\nd by repeat$ te/s1 al?\gh 9 s viol5t a *ange z t m5tion$ above1 ! utmo/ c>e is requir$ to make ! *ange gradually & prev5t compression or break+ ( ! s$im5t lay]4 ,f ?is relation betwe5 ! rate ( filtration & ! loss ( head x is se5 t ! regulation ( ei!r involves ! regulation ( ! o!r1 & x is a matt] ( indiff]5ce :i* is directly & :i* indirectly controll$4 ,,regulation ,,( ,,! ,,rate ,,& ,,loss ,,( ,,head ,,9 ,,! ,,old] ,,filt]s4 ,9 ! old] works1 & 9 fact 9 all b a few ( ! newe/ works1 ! und]dra9s ( ! filt]s connect directly ?r\gh a pipe ) a s+le gate ) ! pure-wat] res]voir or pump-well1 :i* is s built t ! wat] 9 x may rise ne>ly or q z high z t /&+ ^u ! filt]4 ,illu/ration3 ,,fig4 #e4--,,simple/ ,,=m ,,( ,,regulation3 ,,/ralau ,,filt]s ,,at ,,b]l94 ,a typical arrangem5t ( ?is sort 0 us$ at ! ,/ralau works at ,b]l9 7n[ discont9u$71 ,fig4 #e4 ,) ?is arrangem5t ! rate ( filtration is dep5d5t ^u ! height ( wat] 9 ! res]voir or pump-well1 & s ^u ! v>y+ consumption4 ,:5 ! wat] 9 ! receptacle falls ) increas+ consumption ! head is increas$1 & ) x ! rate ( filtration1 :ile1 on ! o!r h&1 ) decreas+ draft & ris+ wat] 9 ! res]voir1 ! rate ( filtration decreases & w\ld ev5tually be /opp$ if no wat] 7 us$4 ,?is v simple arrangem5t ?us automatically1 )9 limits1 adju/s ! rate ( filtration to ! consumption1 & at ! same "t always gives ! highe/ possible level ( wat] 9 ! pump-well1 ?us also economiz+ ! coal requir$ = pump+4 ,9 plants ( ?is type ! loss ( head may be measur$ by floats on little res]voirs built = t purpose1 connect$ ) ! und]dra9s2 b m (t5 !re is no means ( det]m9+ x1 al?\gh ! maximum loss ( head at any "t is ! diff]5ce betwe5 ! levels ( ! wat] on ! filt] & 9 ! res]voir1 or ! outlet ( ! dra9-pipe1 9 case ! latt] is above ! wat]-l9e 9 ! res]voir4 ,! rate ( filtration c only be measur$ ) ?is arrangem5t by %utt+ (f ! incom+ wat] = a def9ite int]val1 & obs]v+ ! di/ance t ! wat] on ! filt] s9ks4 ,! incom+ wat] is regulat$ simply by a gate1 :i* a workman op5s or closes f "t to "t to hold ! requir$ height ( wat] on ! filt]4 ,! only possible regulation ( ! rate & loss ( head is effect$ by a p>tial clos+ ( ! gate on ! outlet-pipe1 by :i* ! fre%ly-clean$ filt]s ) ne>ly-clos$ gates are kept f filt]+ m rapidly ?an ! clogg$ filt]s1 ! gates ( :i* are op5$ wide4 ,(t51 h[ev]1 ?is is n done1 & !n ! fre% filt]s filt] _m times z rapidly z ^? :i* are p>tially clogg$4 ,a majority ( ! filt]s n[ 9 use are built m or less ^u ?is plan1 includ+ mo/ ( ^? 9 ,london & also ! ,altona works1 :i* _h su* a favorable record ) *ol]a 9 #ahib4 ,! inv5tion & application ( me?ods ( bact]ial exam9ation 9 ! la/ ye>s h l$ to diff]5t ideas ( filtration f ^? :i* influ5c$ ! con/ruction ( ! e>li] plants4 ,z a result x is n[ reg>d$ z ess5tial by mo/ ,g]man eng9e]s#ad t ea* filt] %all be provid$ ) devices = measur+ accurately & at any "t bo? ! rate ( filtration & ! loss ( head1 & = controll+ !m1 & also = mak+ ! rate indep5d5t ( consumption by res]voirs = filt]$ wat] l>ge en\gh to balance h\rly v>iations 7capacity #a_/d to #a_/c maximum daily quantity7 & l[ en\gh s t !y c nev] limit ! rate ( filtration by caus+ back-wat] on ! filt]s4 ,^! po9ts are n[ insi/$ ^u by ! ,g]man ,imp]ial ,bo>d ( ,heal?1#ae & all new filt]s are built 9 accordance ) !m1 :ile mo/ ( ! old works are be+ built ov] to con=m to ! requirem5ts4 ,,app>atus ,,= ,,regulat+ ,,! ,,rate ,,& ,,loss ( ,,head4 ,_m appliances h be5 inv5t$ = ! regulation ( ! rate & loss ( head4 ,9 ! app>atus design$ by ,gill & us$ at bo? ,tegel & ,mggel at ,b]l9 ! regulation is effect$ by p>tially clos+ a gate ?r\gh :i* ! efflu5t passes into a *amb] 9 :i* ! wat]-level is practically con/ant 7,fig4 #f74 ,! rate is measur$ by ! height ( wat] on ! weir :i* s]ves z ! outlet = ?is second *amb] into a ?ird connect+ ) ! ma9 res]voir1 :ile ! loss ( head is %[n by ! diff]5ce 9 height ( floats ^u wat] 9 ! fir/ *amb]1 repres5t+ ! pressure 9 ! und]dra9s1 & ^u wat] 9 connection ) ! raw wat] on ! filt]4 ,f ! respective heights ( ! ?ree floats ! att5dant c at any "t see ! rate ( filtration & ! loss ( head1 & :5 a *ange is requir$ x is effect$ by mov+ ! gate4 ,illu/ration3 ,,fig4 #f4--,,regulation ,,app>atus ,,at ,,b]l9 7,,tegel74 ,9 ! app>atus design$ 9 #ahff by ,kirkwood = ,/4 ,l\is & nev] built 7,fig4 #g7 ! loss ( head 0 directly1 & ! rate indirectly1 regulat$ by a movable weir1 :i* 0 to h be5 l[]$ f "t to "t by ! att5dant to secure ! requir$ results4 ,?is plan is especially rem>kable z x meets ! mod]n requirem5ts ( a regul> rate indep5d5t ( rate ( consumption & ( ! wat]-level 9 ! res]voir1 & also all[s cont9ual measurem5ts ( bo? rate 7height ( wat] on ! weir7 & head 7diff]5ce 9 wat]-levels on filt] & 9 efflu5t *amb]7 to be made1 & control ( ! same by ! position ( ! weir4 ,mr4 ,kirkwood f\nd no filt]s 9 ,europe ) su* appliances1 & x 0 _m ye>s aft] 8 report 0 publi%$ be=e simil> devices 7 us$1 b !y are n[ reg>d$ z ess5tial4 ,illu/ration3 ,,fig4 #g4--,,regulation ,,app>atus ,,& ,,section ,,( ,,filt] ,,recomm5d$ ,,= ,,/4 ,,l\is ,,by ,,kirkwood ,,9 #ahff4 ,illu/ration3 ,,fig4 #h4--,,regulation ,,app>atus ,,us$ ,,at ,,hamburg4 ,! regulators = new filt]s at ,hamburg 7,fig4 #h7 are built ^u ! pr9ciple ( ,kirkwood's device1 b provision is made = a second measurem5t ( ! wat] if desir$ by ! loss ( head 9 pass+ a subm]g$ orifice4 ,bo? ! rate & loss ( head are indicat$ by a float on ! fir/ *amb] connect+ directly ) ! und]dra91 :i* at ! same "t indicates ! head on a fix$ scale1 ! z]o ( :i* corresponds to ! height ( ! wat] above ! filt]1 & ! rate ^u a scale mov+ ) ! weir1 ! z]o ( :i* corresponds ) ! edge ( ! weir4 ,! wat] on ! filt] is held at a p]fectly con/ant level4 ,! regulators 9 use at ,worms & ^? rec5tly introduc$ at ,magdeburg act ^u ! same pr9ciple1 b ! levels ( ! wat] on ! filt]s are all[$ to fluctuate1 & ! weirs & 9 fact1 ! :ole regulat+ appliances are m\nt$ on big floats 9 surr\nd+ *amb]s ( wat] connect+ ) ! unfilt]$ wat] on ! filt]s4 ,i am unable to f9d any advantages 9 ^! appliances1 & !y are mu* m complicat$ ?an ! =ms %[n by ! cuts4 ,,app>atus ,,= ,,regulat+ ,,! ,,rate ,,directly4 ,illu/ration3 ,,fig4 #i4--,,l9dley',s ,,regulation ,,app>atus ,,at ,,w>saw1 ,,russia4 ,! above-m5tion$ regulators control directly ! loss ( head1 & only indirectly ! rate ( filtration4 ,! regulators at ,w>saw 7 design$ by ,l9dley to regulate ! rate directly & make x indep5d5t ( ! loss ( head4 ,! quantity ( wat] fl[+ away is regulat$ by a float ^u ! wat] 9 ! efflu5t *amb]1 :i* holds ! top ( ! telescope outlet-pipe a con/ant di/ance bel[ ! surface & s secures a con/ant rate4 ,z ! friction ( ! filt] increases ! float s9ks ) ! wat] until x rea*es bottom1 :5 ! filt] mu/ be scrap$4 ,a c\nt]-weight r$uces ! weight on ! float1 & at ! same "t all[s a *ange 9 ! rate :5 desir$4 ,?is app>atus is automatic4 ,all ( ! o!r =ms describ$ require to be occasionally adju/$ by ! att5dant1 b ! att5tion !y require is v slight1 & wat*m5 are always on duty at l>ge plants1 :o c easily wat* ! regulators4 ,! ,w>saw app>atus is report$ to "w v satisfactorily1 no tr\ble be+ exp]i5c$ ei!r by leak+ or /ick+ ( ! telescope-jo9t1 :i* is obvi\sly ! weake/ po9t ( ! device1 b =tunately a p]fectly tight jo9t is n ess5tial to ! success ( ! app>atus4 ,regulators act+ ^u ! same pr9ciple h rec5tly be5 in/all$ at ,zri*1 :]e !y are op]at+ successfully4 ,burton#af has describ$ an +5i\s device design$ by him = ! filt]s at ,tokyo1 ,japan4 ,x consi/s ( a d\ble act+ valve ( gun metal 7simil> to t %[n by ,fig4 #aa71 ?r\gh :i* ! efflu5t mu/ pass4 ,?is valve is op5$ & clos$ by a rod connect+ ) a pi/on 9 a cyl9d]1 ! opposite sides ( :i* connect ) ! efflu5t pipe above & bel[ a po9t :]e ! latt] is p>tially clos$1 s t ! valve is op5$ & clos$ accord+ z ! loss ( head 9 pass+ ?is ob/ruction is bel[ or above ! am\nt correspond+ to ! desir$ rate ( filtration4 ,! use ( ! ,v5turi met] 9 connection ) ! regulation ( filt]s w\ld make an int]e/+ /udy1 & has1 ,i believe1 nev] be5 consid]$4 ,illu/ration3 ,,regulator-,,h\se1 ,,%[+ ,,rate ,,( ,,filtration ,,& ,,loss ,,( ,,head ,,on ,,! ,,outside1 ,,brem54 ,illu/ration3 ,,inlet ,,= ,,admission ,,( ,,raw ,,wat] ,,to ,a ,,filt]1 ,,ea/ ,,london4 ,to face page #eh4 ,,app>atus ,,= ,,regulat+ ,,! ,,height ,,( ,,wat] ,,^u ,,filt]s4 ,x w be se5 by ref]5ce to ! diagrams ( ! ,b]l9 & ,hamburg efflu5t regulators 7,figs4 #f & #h7 t _! p]fect op]ation is dep5d5t ^u ! ma9t5ance ( a con/ant wat]-level ^u ! filt]s4 ,! old-fa%ion$ adju/m5t ( ! inlet-gate by ! att5dant is h>dly accurate en\gh4 ,! fir/ app>atus = accurately & automatically regulat+ ! level ( ! wat] ^u ! filt]s 0 con/ruct$ at ,leeuw>d51 ,holl&1 by ! eng9e]1 ,mr4 ,halb]tsma1 :o has s9ce us$ a simil> device at o!r places1 & improv$ =ms ( :i* are n[ us$ at ,b]l9 & at ,hamburg4 ,at ,b]l9 7,mggel7 ! wat]-level is regulat$ by a float ^u ! wat] 9 ! filt] :i* op5s or %uts a balanc$ d\ble valve on ! inlet-pipe directly b5ea?1 z %[n 9 ,fig4 #aj4 ,x is n at all necess>y t ?is valve %\ld %ut wat]-tight2 x is only necess>y t x %\ld prev5t ! cont9u\s infl[ f becom+ s great z to raise ! wat]-level1 & = ?is reason loose1 easily-work+ jo9ts are employ$4 ,! app>atus is plac$ 9 a little pit next to ! side ( ! filt]1 & ! ov]fl[+ wat] is prev5t$ f wa%+ ! s& by pav+ ! s& ar\nd x = a few feet4 ,illu/ration3 ,,fig4 #aj4--,,regulation ,,( ,,infl[ ,,us$ ,,at ,m,,ggel1 ,,b]l94 ,at ,hamburg ! same result is obta9$ by putt+ ! valve 9 a special *amb] outside ( ! filt] & connect$ ) ! float by a walk+-beam 7,fig4 #aa74 ,illu/ration3 ,,fig4 #aa4--,,regulation ,,( ,,infl[ ,,us$ ,,at ,,hamburg4 ,! v>i\s regulators require to be protect$ f cold & ice by special h\ses1 except 9 ! case ( cov]$ filt]s1 :]e !y c usually be arrang$ ) advantage 9 ! filt] itself4 ,9 reg>d to ! *oice ( ! =m ( regulator = bo? ! inlets & outlets ( filt]s1 s f> z ,i h be5 able to asc]ta91 ea* ( ! mod]n =ms describ$ z 9 use p]=ms its functions satisfactorily1 & 9 special cases any ( !m c\ld prop]ly be select$ :i* w\ld 9 ! local conditions be ! simple/ 9 con/ruction & op]ation4 ,,limit ,,to ,,! ,,loss ,,( ,,head4 ,! ext5t to :i* ! loss ( head is all[$ to g be=e filt]s are clean$ diff]s widely 9 ! diff]5t works1 "s ( ! new] works limit+ x %>ply because x is believ$ t l[ bact]ial effici5cy results :5 ! pressure is too great1 al?\gh ! frequ5cy ( clean+ & consequ5tly ! co/ ( op]ation are !reby increas$4 ,at ,d>l+ton1 ,engl&1 ,i believe z a result ( ! ,g]man !ories1 ! loss ( head is limit$ to ab\t #ah in*es by a masonry weir built )9 ! la/ few ye>s4 ,at ,b]l91 bo? at ,tegel & ,mggel1 ! limit is #bd in*es1 :ile at ! new ,hamburg works #bh in*es are all[$4 ,at ,/ralau 9 #ahic an ef=t 0 made to n exce$ a limit ( #dj in*es1 b previ\sly heads up to #fj in*es 7 us$1 :i* corresponds ) ! #ef in*es us$ at ,altona2 &1 9 ! o!r old works1 :ile exact in=mation is n easily obta9$ because ( imp]fect records1 ,i am conv9c$ t heads ( #fj or ev5 #hj in*es are n uncommon4 ,at ! ,lawr5ce ,exp]im5t ,/ation heads ( #gj in*es h g5]ally be5 us$1 al?\gh "s filt]s h be5 limit$ to #cf & #bd in*es4 ,9 #ahff ,kirkwood became conv9c$ t ! loss ( head %\ld n g mu* above #cj in*es1 fir/1 because high heads w\ld1 by br++ extra weight ^u ! s&1 make x too compact1 &1 second1 because :5 ! pressure became too great ! s$im5t lay] on ! surface ( ! s&1 9 :i* mo/ ( ! loss ( head occurs1 w\ld no long] be able to support ! weight &1 becom+ brok51 w\ld all[ ! wat] to p\r ?r\gh ! comp>atively l>ge result+ op5+s at greatly increas$ rates & ) r$uc$ effici5cy4 ,9 reg>d to ! fir/ po9t1 a /raight1 ev5 pressure _m times t ( ! wat] on ! filt] is incapable ( compress+ ! s&4 ,x is mu* m ! effect ( ! boots ( ! workm5 :5 scrap+ t makes ! s& compact4 ,i h f\nd s& 9 natural banks at ,lawr5ce #gj or #hj feet bel[ ! surface1 :]e x _h be5 subject$ to correspond+ pressure = ?\s&s ( ye>s1 to be q z por\s z :5 pack$ 9 wat] 9 exp]im5tal filt]s 9 ! usual way4 ,! second reason m5tion$1 or1 z ,i may call x1 ! break+-?r\gh !ory1 is v g5]ally if n univ]sally accept$ by ,g]man eng9e]s1 & ?is is ! reason = ! l[ limit commonly adopt$ by !m4 ,a c>eful /udy ( ! results at ,lawr5ce fails to %[ ! slighte/ det]ioration ( ! efflu5ts up to ! limit us$1 #gb in*es4 ,?us 9 #ahib1 tak+ only ! results ( ! cont9u\s filt]s ( full height 7,nos4 #cc;,a1 #cd;,a1 #cf;,a1 & #cg71 we f9d t = ! ?ree days be=e scrap+1 :5 ! head 0 ne>ly #gb in*es1 ! av]age numb] ( bact]ia 9 ! efflu5ts 0 #ca p] cc41 :ile = ! ?ree days aft] scrap+1 ) v l[ heads1 ! numb] 0 #dg4 ,! correspond+ numb]s ( ,b4 prodigiosus#ag 7 #a4a & #b4g4 ,?is %[s bett] "w ) ! highe/ heads1 b is op5 to ! objection t ! p]iod j aft] scrap+1 ow+ to ! di/urbance ( ! surface1 is commonly suppos$ to be a p]iod ( l[ effici5cy4 ,to avoid ?is criticism 9 calculat+ ! correspond+ results = #ahic1 ! numb]s ( ! bact]ia = ! int]m$iate days :i* c\ld n h be5 influ5c$ ei!r by scrap+ or by excessive head are put side by side ) ! o!rs4 ,tak+ ^! results z be=e = cont9u\s filt]s #gb in*es high1 & exclud+ ^? ) extremely f9e s&s & a filt] :i* 0 only 9 op]ation a %ort "t t[>d ! end ( ! ye>1 we obta9 ! foll[+ results3 ,wat] ,b4 ,bact]ia ,prodigiosus p] cc4 p] cc4 ,av]age #a/ day aft] scrap+1 l[ heads #gi #f4a ,av]age #b;d day aft] scrap+1 l[ heads #dd #d4a ,av]age #c;d day aft] scrap+1 l[ heads #de #c4f ,int]m$iate days1 m$ium heads #ei #d4e ,second f la/ day1 heads ( ne>ly #gb in*es #ff #b4g ,next to ! la/ day1 heads ( ne>ly #gb in*es #ef #c4b ,la/ day1 heads ( ne>ly #gb in*es #hc #b4e ,^! figures %[ a v slight increase ( ! wat] bact]ia 9 ! efflu5t z ! head approa*es ! limit1 b no su* increase z might be expect$ f a break+ ?r\gh ( ! s$im5t lay]1 & ! ,b4 prodigiosus :i* is believ$ to bett] indicate ! removal ( ! bact]ia ( ! orig9al wat]1 actually %[s a decrease1 ! la/ day be+ ! be/ day ( ! :ole p]iod4 ,! ,lawr5ce results1 !n1 uni=mly & cle>ly po9t to a conclusion directly opposite to ! commonly accept$ view1 & ,i h ?us be5 l$ to exam9e some:at closely ! gr\nds ^u :i* ! break+-?r\gh !ory re/s4 ,! two works :i* h p]haps contribut$ mo/ to ! !ories ( filtration are ! ,/ralau & ,altona works4 ,aft] exam9+ ! available records ( ^! works1 ,i am q conv9c$ t at ^! places !re has be51 at times at lea/1 decreas$ effici5cy ) high heads4 ,= ! ,/ralau works ?is is well %[n by ,piefke's plates 9 ! ,zeits*rift fr ,hygi5e1 #ahid1 aft] page #ahh4 ,9 bo? ( ^! works1 h[ev]1 ! app>atus 7or lack ( app>atus7 = regulat+ ! rate is t %[n by ,fig4 #e1 page #di1 & ! rate ( filtration is ?us dep5d5t ^u ! rate ( consumption & ! height ( wat] 9 ! res]voir4 ,at ! ,/ralau works1 at ! "t cov]$ by ! above-m5tion$ diagrams1 ! daily quantity ( wat] filt]$ 0 #bg times ! capacity ( ! res]voir1 & ! rate ( filtration mu/ consequ5tly h adapt$ itself to ! h\rly consumptions4 ,! data :i* =m$ ! basis ( ,kirkwood's conclusions are n giv5 9 detail1 b x is q safe to assume t !y 7 obta9$ f filt]s regulat$ z ^? at ,altona & ,/ralau are regulat$1 & :at is said 9 reg>d to ! latt] w apply equally to 8 results4 ,piefke#ah %[s t among ! sep>ate filt]s at ,/ralau1 all connect$ ) ! same pure-wat] res]voir1 ^? connect$ ?r\gh ! %ort] pipes gave poor] efflu5ts ?an ! m remote filt]s1 & he attributes ! diff]5ce to ! frictional resi/ance ( ! connect+ pipes1 :i* help$ to prev5t excessive rates 9 ! filt]s f>!/ away :5 ! wat] 9 ! res]voir became l[1 & ?us ! fluctuations 9 ! rates 9 ^! filt]s 7 less ?an 9 ^? close to ! res]voir4 ,he does n1 h[ev]1 notice1 9 speak+ ( ! filt]s 9 :i* ! decreas$ effici5cies ) high heads 7 specially m>k$1 t !y foll[ 9 ne>ly ! same ord]1 & t ( ! f\r op5 filt]s m5tion$ ?ree 7 ne> ! res]voir & only "o 0 sep>at$ by a comp>atively long pipe1 indicat+ t ! det]ioration ) high heads 0 only noticeable1 or at lea/ 0 mu* m conspicu\s1 9 ^? filt]s :]e ! rates fluctuat$ mo/ viol5tly4 ,x requires no elaborate calculation to %[ t ( two filt]s connect$ ) ! same pure-wat] res]voir1 z %[n by ,fig4 #e1 ) only simple gates on ! connect+ pipes1 "o ( !m clean & ?rottl$ by a ne>ly clos$ gate1 s t ! normal pressure beh9d ! gate is above ! highe/ level ( wat] 9 ! res]voir1 & ! o!r clogg$ s t ! normal pressure ( ! wat] 9 ! dra9 is consid]ably bel[ ! highe/ level ( ! wat] 9 ! res]voir1 ! latt] w suff] mu* ! m sev]e %ocks ) fluctuat+ wat]-levels2 & ! fact be+ admitt$ t fluctuat+ levels are unfavorable1 we mu/ g f>!r & conclude t ! detrim5tal action w increase ) increas+ loss ( head4 ,i am incl9$ to ?9k t ?is !ory is adequate to expla9 ! ,/ralau & ,altona results )\t res\rce to ! break+-?r\gh !ory4 ,:ile ! above does n at all prove ! break+-?r\gh !ory to be false1 x expla9s ! results ^u :i* x re/s 9 ano!r way1 & c h>dly fail to ?r[ s mu* d\bt ^u x z to make u refuse to all[ its application to ^? works :]e a regul> rate ( filtration is ma9ta9$ reg>dless ( v>iations 9 ! consumption1 until pro( is furni%$ t x is applicable to !m4 ,i h be5 totally unable to f9d satisfactory ,european results 9 reg>d to ?is po9t4 ,! ,engli% works c furni% no?+1 bo? on acc\nt ( ! lack ( regulat+ appliances & because ! mon?ly bact]ial exam9ations are inadequate = a discussion ( h\rly or daily *anges4 ,! results f ! old] ,cont95tal works are also exclud$ = "o or ! o!r1 or m (t5 = bo?1 ( ! above reasons4 ,! ,hamburg1 ,tegel1 & ,mggel results1 s f> z !y g1 %[ no det]ioration ) increas$ heads1 b ! heads are limit$ to #bd or #bh in*es by ! con/ruction ( ! filt]s1 & ! results ?us entirely fail to %[ :at w\ld be obta9$ ) heads m ?an twice z high4 ,i am ?us =c$ to conclude t !re is no adequate evid5ce ( inf]ior effici5cy ) high heads 9 filt]s :]e ! rates are indep5d5t ( ! wat]-level 9 ! pure-wat] res]voir1 ! only results directly to ! po9t--! ,lawr5ce results m5tion$ above--indicat+ t ! full effici5cy is ma9ta9$ ) heads rea*+ at lea/ #gb in*es4 ,! pr9cipal reason = desir+ to all[ a consid]able loss ( head is an economical "o2 ! p]iod w !n be l5g!n$1 :ile ! frequ5cy ( scrap+ & ! volume ( s& to be wa%$ & replac$ w be correspond+ly r$uc$4 ,!re may be o!r advantages 9 long p]iods1 su* z less tr\ble ) scrap+ & bett] "w 9 cold w9t] wea!r1 b ! co/ is ! mo/ important consid]ation4 ,x is ! preval5t idea among ! ,g]man eng9e]s t ! loss ( head aft] rea*+ #bd to #cj in*es w\ld increase v rapidly1 s t ! quantity ( wat] filt]$1 9 case a mu* high] head 0 all[$1 w\ld n be mat]ially increas$4 ,no c>eful inve/igations1 h[ev]1 h be5 made1 & inde$ !y are h>dly possible ) exi/+ arrangem5ts1 z 9 ! old] filt]s ! loss ( head fluctuates ) v>y+ rates ( filtration 9 su* a way t only results ( v d\btful value c be obta9$1 & 9 ! new] works ! loss ( head is too closely limit$1 & ! curves :i* c be drawn by extrapolation are evid5tly no safe indications ( :at w\ld actually happ5 if ! process 0 c>ri$ f>!r4 ,on ! o!r h&1 ,i 0 told by ! att5dant at ,d>l+ton1 ,engl&1 t s9ce ! build+ ( ! weir a few ye>s ago1 :i* n[ limits ! loss ( head to ab\t #ah in*es in/ead ( ! #e feet or m =m]ly us$1 ! quantity ( s& to be remov$ has be5 ?ree times z great z =m]ly4 ,no records are kept1 & ?is c only be giv5 z ! g5]al impression ( ! man :o sup]9t5ds ! "w4 ,at ,lawr5ce ! av]age quantities ( wat] filt]$ betwe5 scrap+s ) s& ( an effective size ( #j4bj mm4 h be5 z foll[s3 ,maximum ,loss ( ,million ,gallons p] ,acre filt]$ ,head4 betwe5 ,scrap+s4 #ahib4 #ahic4 ,av]age4 #gj in*es #eh #hh #gc #cd foot #cb #bb #bg #bb foot #ag #af #af ,) s& ( an effective size ( #j4bi mm4 ! results 73 #ahic4 #gj in*es #gj #bb foot #bi ,^! results indicate a great increase 9 ! quantity ( wat] filt]$ betwe5 scrap+s ) increas+ heads1 ! figures be+ ne>ly proportional to ! maximum heads us$ 9 ! respective cases4 ,x is1 ( c\rse1 q possible t ! results w\ld diff] 9 diff]5t places ) ! "* ( ! raw wat] & ( ! filt]+ mat]ial4 ,! dep? ( s& to be remov$ by scrap+ at "o "t is1 )9 limits1 practically indep5d5t ( ! quantity ( dirt :i* x has accumulat$1 & any l5g!n+ ( ! p]iod means a correspond+ r$uction 9 ! quantity ( s& to be remov$1 wa%$ & replac$ & consequ5tly an important r$uction 9 ! op]at+ co/1 z well z a r$uction 9 ! area ( filt]s out ( use :ile be+ clean$1 & s1 9 ! capital co/4 ,among ! m9or objections to an increas$ loss ( head are ! great] head aga9/ :i* ! wat] mu/ be pump$1 & ! possible increas$ difficulty ( fill+ filt]s ) filt]$ wat] f bel[ aft] scrap+1 b ^! w\ld h>dly h mu* weight aga9/ ! economy indicat$ by ! ,lawr5ce exp]im5ts = ! high] heads4 ,high heads w also drive an increas$ quantity ( wat] ?r\gh any cracks or passages 9 ! filt]4 ,su* leaks h at la/ be5 f\nd to be ! cause ( ! inf]ior "w ( ! cov]$ filt]s at ,/ralau1 ! wat] go+ d[n unfilt]$ 9 c]ta9 corn]s1 especially at high heads2 b ) c>eful con/ruction !re %\ld be no cracks1 & ) ! aid ( bact]iology to f9d ! possible leaks ?is ought n to be a valid objection4 ,9 conclusion3 ! tr5d ( op9ion is /rongly 9 favor ( limit+ ! loss ( head to ab\t #bd to #cj in*es z 0 sugge/$ by ,kirkwood1 b ,i am =c$ to conclude t !re is reason to believe t equally good results c be obta9$ ) l[] op]at+ exp5ses by all[+ high] heads to be us$1 at lea/ 9 ! case ( filt]s ) mod]n regulat+ appliances1 &1 ,i w\ld sugge/ t filt]s %\ld be built s z n to exclude ! use ( mod]ately high heads1 & t ! limit to be p]man5tly us$ %\ld be det]m9$ by actual te/s ( effici5cy & l5g? ( p]iod ) v>i\s losses ( head aft] />t+ ! works4 ,,*apt] ,v4 ,,clean+ ,,filt]s4 ,:5 a filt] has become s f> clogg$ t x w no long] pass a satisfactory quantity ( wat] ) ! all[able head x mu/ be clean$ by scrap+ (f & remov+ ! upp] lay] ( dirty s&4 ,to d ?is )\t unnecess>y loss ( "t ! unfilt]$ wat] /&+ ^u ! filt] is remov$ by a dra9 above ! s& provid$ = t purpose4 ,! wat] 9 ! s& mu/ !n be l[]$ bel[ ! surface ( ! s& by draw+ wat] f ! und]dra9s until ! s& is firm en\gh to be> ! weight ( ! workm54 ,by ! "t t ?is is accompli%$ ! la/ wat] on ! surface %\ld h soak$ away1 & ! filt] is ready to be scrap$4 ,?is is done by workm5 ) wide1 %>p %ovels1 & ! s& remov$ is tak5 to ! s&-wa%+ app>atus to be wa%$ & us$ aga94 ,special pa9s are giv5 to secur+ rapid & *eap transportation ( ! s&4 ,9 "s cases x is :eel$ out ( ! filt] on an incl9$ plane to ! wa%]4 ,9 o!r cases a movable crane is provid$ :i* lifts ! s& 9 special receptacles & all[s x to fall into c>s on a tram-l9e on :i* ! crane also moves4 ,! c>s z fill$ are run to ! wa%] & also s]ve to br+ back ! wa%$ s&4 ,:5 ! dirty s& has be5 remov$1 ! surface ( ! s& is c>efully smoo!d & rak$4 ,?is is especially necess>y to remove ! effects ( ! workm5's boots4 ,x is cu/om>y 9 ! mo/ c>efully manag$ works to fill ! s& ) filt]$ wat] f bel[1 introduc$ ?r\gh ! und]dra9s4 ,9 case ! ord9>y level ( ! wat] 9 ! pure-wat] canal is high] ?an ! surface ( ! s& 9 ! filt]s1 ?is is accompli%$ by simply op5+ a gate provid$ = ! purpose1 :i* all[s ! wat] to pass ar\nd ! regulat+ app>atus4 ,o!rwise filt]s c be fill$ f a special pipe tak+ its wat] f any filt] :i* at t "t c deliv] its efflu5t high en\gh = t purpose4 ,! quantity ( wat] requir$ = fill+ ! s& f bel[ is ord9>ily b a fraction ( "o p] c5t ( ! quantity filt]$4 ,=m]ly1 in/ead ( fill+ f bel[1 aft] clean+1 ! raw wat] 0 br\ght directly onto ! surface ( ! filt]4 ,?is 0 said to only imp]fectly fill ! s&-pores1 :i* /ill conta9$ mu* air4 ,if1 h[ev]1 ! wat] is n br\ght on too rapidly x w s9k into ! s& ne> ! po9t :]e x is appli$1 pass lat]ally ?r\gh ! s& or und]ly+ gravel to o!r p>ts ( ! filt]1 & !n rise1 s t ev5 9 ?is case all b a little ( ! filt] w be really fill$ f bel[4 ,?is is1 h[ev]1 op5 to ! objection t h[ev] sl[ly ! wat] is introduc$1 ! s& :i* absorbs x ar\nd ! inlet filt]s x at a v high rate & presumably imp]fectly1 s t ! wat] 9 ! und]dra9s at ! />t w be poor quality & ! s& ar\nd ! inlet w be unduly clogg$4 ,! practice ( fill+ f bel[ is !re=e well f\nd$4 ,z soon z ! surface ( ! s& is cov]$ ) ! wat] f bel[1 raw wat] is introduc$ f above1 fill+ ! filt] to ! /&>d height1 c>e be+ tak5 at fir/ t no curr5ts are produc$ :i* might wa% ! surface ( ! s&4 ,x has be5 recomm5d$ by ,piefke & o!rs t ?is wat] %\ld be all[$ to /& = a "t up to tw5ty-f\r h\rs be=e />t+ ! filtration1 to all[ ! =mation ( a s$im5t lay]1 & 9 "s places1 especially at ,b]l9 & ! works ( "s ( ! ,london companies1 ?is is done2 b v>y+ importance is atta*$ to ! proc$ure1 & x is inv>iably omitt$1 s f> z ,i c le>n1 :5 ! dem& = wat] is heavy4 ,! dep? ( s& remov$ by scrap+ mu/ at lea/ equal ! dep? ( ! discolor$ lay]1 b !re is no %>p divid+ l9e1 ! impurities gradually decreas+ f ! surface d[nw>d4 ,fig4 #ab %[s ! relative numb] ( bact]ia f\nd 9 ! s& at v>i\s dep?s 9 "o ( ! ,lawr5ce exp]im5tal filt]s1 & is a repres5tative result1 al?\gh ! actual numb]s v>y at diff]5t times4 ,9 g5]al x may be said t ! bulk ( ! s$im5t is reta9$ 9 ! upp] qu>t] in*1 b x is desirable to remove also ! less dirty s& bel[ &1 9 fact1 x is app>5tly impossible ) ! me?od ( scrap+ 9 use to remove s ?9 a lay] z "o f\r? in*4 ,practically ! dep? to :i* s& is remov$ is /at$ to be f #j4dj to #a4bj in*4 ,exact /ati/ics are n easily obta9$1 b ,i ?9k t #b c5timet]s or #j4gi in* may be safely tak5 z ab\t ! av]age dep? usually remov$ 9 ,european filt]s1 & x is ?is dep? :i* is indicat$ on ,fig4 #ab4 ,illu/ration3 ,,fig4 #ab4--;,,diagram ,,%[+ ,,accumulation ,,( ,,bact]ia ,,ne> ,,! ,,surface ,,( ,,! ,,s&4 ,at ! ,lawr5ce ,exp]im5t ,/ation1 ! dep? remov$ is (t5 mu* less ?an ?is1 & dep5ds ^u ! size ( gra9 ( ! s& employ$1 ! co>s] s&s requir+ to be m deeply scrap$ ?an ! f9] ones4 ,! me?od ( scrap+1 h[ev]1 :i* all[s ! removal ( v ?9 s& lay]s1 is only possible because ( ! small size ( ! filt]s1 & z x is incapable ( application on a l>ge scale1 ! dep?s ?us remov$ are only int]e/+ z %[+ ! results :i* might be obta9$ 9 practice ) a m p]fect me?od ( scrap+4 ,! replac+ ( ! wa%$ s& is usually delay$ until ! filt] has be5 scrap$ q a numb] ( times--commonly = a ye>4 ,! la/ scrap+ be=e refill+ is mu* deep] ?an usual1 because ! s& bel[ ! dep? ( ! ord9>y scrap+ is some:at dirty1 & might cause tr\ble if left bel[ ! clean s&4 ,9 ,engl& x is ! usual if n ! univ]sal practice to replace ! wa%$ s& at ! bottom betwe5 ! old s& & ! gravel4 ,?is is done by digg+ up ! entire filt] 9 sections ab\t six feet wide4 ,! old s& 9 ! fir/ section is remov$ cle> d[n to ! gravel1 & ! dep? ( wa%$ s& :i* is to be replac$ is put 9 its place4 ,! old s& f ! next six-foot section is !n %ovell$ ^u ! fir/ section ( clean s&1 & its place is 9 turn fill$ ) fre% s&4 ,) ?is practice ! workm5's boots are likely to di/urb ! gravel ea* ye>1 necessitat+ a ?ick] lay] ( ! upp] & f9e/ grade ?an w\ld o!rwise be requir$4 ,9 ,g]many ?is is also sometimes done1 b m frequ5tly ! upp] lay] ( slightly clogg$ s& bel[ ! regul> scrap+ is remov$ z f> z ! slighte/ discoloration c be se51 p]haps #f in*es deep4 ,! s& bel[ is loos5$ = ano!r #f in*es & all[$ to /& dry1 if possible1 = "s days2 aft]w>ds ! wa%$ s& is br\ght on & plac$ above4 ,! wa%$ s& is nev] replac$ )\t "s su* treatm5t1 because ! slightly clogg$ s& bel[ ! lay] remov$ w\ld act z if f9] ?an ! fre%ly wa%$ s&1#ai & !re w\ld be a t5d5cy to sub-surface clogg+4 ,,frequ5cy ,,( ,,scrap+4 ,! frequ5cy ( scrap+ dep5ds ^u ! "* ( ! raw wat]1 ! ?or\ghness ( ! prelim9>y s$im5tation1 ! gra9-size ( ! filt] s&1 ! rate ( filtration1 & ! maximum loss ( head all[$4 ,) suitable conditions ! p]iod betwe5 scrap+s %\ld nev] be less ?an "o week1 & w b r>ely exce$ two mon?s4 ,"u exceptional conditions1 h[ev]1 p]iods h be5 record$ z l[ z "o day & z high z "o hundr$ & t5 days4 ,p]iods ( less ?an a week's duration are almo/ conclusive evid5ce t some?+ is radically wrong1 & ! p]iods ( "o day m5tion$ 7 actually accompani$ by v inadequate filtration4 ,9 #ahib ! av]age p]iods at ! ,g]man works v>i$ f #i4e days at ,/ett9 7) an excessive rate7 to #dj days at ,brunswick1 ! av]age ( all be+ #be days4#bj ,! quantity ( wat] p] acre filt]$ betwe5 scrap+s =ms ! mo/ conv5i5t basis = calculation4 ,! effect ( rate 7page #di71 loss ( head 7page #fe71 & size ( s& gra9 7page #cb7 h already be5 discuss$1 & x w suffice to say "h t ! total quantity filt]$ betwe5 scrap+s is app>5tly indep5d5t ( ! rate ( filtration1 b v>ies ) ! maximum loss ( head & ) ! gra9-size ( ! s&1 & app>5tly ne>ly 9 proportion to !m4 ,elev5 ,g]man filt]-works 9 #ahib1 draw+ _! wat]s f riv]s1 filt]$ on an av]age #ea million gallons ( wat] p] acre betwe5 scrap+s1 ! s+le results rang+ f #bh at ,brem5 to #ga at ,/uttg>t1 :ile ,zri*1 draw+ its wat] f a lake :i* is b v r>ely turbid1 filt]$ #bfj million gallons p] acre betwe5 scrap+s4 ,un=tunately1 ! quantities at ,b]l91 :]e 79 #ahib two ?irds & n[ all7 ! wat] is drawn f comp>atively l>ge ponds on ! riv]s1 are n available = comp>ison4 ,at ,london1 9 #ahhd1 ! av]age quantities ( wat] filt]$ betwe5 scrap+s v>i$ f #dc to #acf million gallons p] acre ) ! diff]5t companies1 av]ag+ #he1 & 9 #ahib ! quantities rang$ f #gc to #aeg1 av]ag+ #ij million gallons p] acre4 ,! great] quantity filt]$ at ,london may be due to ! great] sizes ( ! s$im5tation-bas9s1 :i* = all ! companies toge!r hold a n9e days' supply at ,london aga9/ probably less ?an "o day's supply = ! ,g]man works4 ,!re is little in=mation available 9 reg>d to ! frequ5cy ( scrap+ ) wat] drawn f imp\nd+ res]voirs4 ,9 "s exp]im5ts made by ,mr4 ,fitz,gerald at ! ,*e/nut ,hill res]voir1 ,bo/on1 ! results ( :i* are z yet unpubli%$1 a filt] ) s& ( an effective size ( only 4#ji mm4 av]ag$ #eh million gallons p] acre betwe5 scrap+s = n9e p]iods1 ! rate ( filtration be+ #a4ej million gallons p] acre daily1 :ile ano!r filt]1 ) s& ( an effective size ( 4#ah mm41 pass$ an av]age ( #ic million gallons p] acre = t5 p]iods at ! same rate4 ,^! exp]im5ts ext5d$ ?r\gh all seasons ( ! ye>1 & tak+ into acc\nt ! comp>ative f95ess ( ! s&s !y %[ r high quantities ( wat] filt]$ betwe5 scrap+s4 ,! quantity ( wat] filt]$ betwe5 scrap+s is usually greate/ 9 w9t]1 ow+ to ! small] quantity ( s$im5t 9 ! raw wat] at ?is season1 & is l[e/ 9 times ( flood1 reg>dless ( season4 ,9 summ] ! quantity is (t5 r$uc$ to a v l[ figure 9 wat]s support+ alg gr[?s1 especially :5 ! filt]s are n cov]$4 ,?us at ,/ralau 9 #ahic dur+ ! alg p]iod ! quantity 0 r$uc$ to #ad million gallons p] acre = op5 filt]s1#ba b ?is 0 q exceptional1 ! mu*-pollut$1 ?\gh comp>atively cle>1 ,spree wat] furni%+ unusually favorable conditions = ! alg4 ,,quantity ,,( ,,s& ,,to ,,be ,,remov$4 ,9 reg>d to ! quantity ( s& to be remov$ & wa%$1 if we take ! av]age result giv5 above = ! ,g]man works filt]+ riv]-wat]s ( #ea1jjj1jjj gallons p] acre filt]$ betwe5 scrap+s1 & ! dep? ( s& remov$ at two c5timet]s or #j4gi in*1 we f9d t "o volume ( s& is requir$ = e #bcge volumes ( wat] filt]$1 or #b4aj cubic y>ds p] million gallons4 ,at ,brem51 ! highe/ av]age result1 ! quantity w\ld be #c4hj y>ds1 & at ,/ralau dur+ ! alg season #g4gj y>ds4 ,at ,zri*1 on ! o!r h&1 ! quantity is only #j4da y>d1 & at ,london1 ) #hg1jjj1jjj gallons p] acre filt]$ betwe5 scrap+s1 ! quantity ( s& wa%$ w\ld be #a4bd y>ds p] million gallons2 assum+ always t ! lay] remov$ is #j4gi in* ?ick4 ,^! e/imates are = ! regul> scrap+s only1 & d n include ! annual deep] scrap+ be=e replac+ ! s&1 :i* w\ld increase !m by ab\t "o ?ird4 ,,wa/+ ,,! ,,efflu5ts ,,aft] ,,scrap+4 ,x has already be5 /at$ t an important "p ( ! filtration takes place 9 ! s$im5t lay] deposit$ on top ( ! s& f ! wat]4 ,:5 ?is lay] is remov$ by scrap+ its influ5ce is tempor>ily remov$1 & r$uc$ effici5cy ( filtration may result4 ,! significance ( ?is r$uc$ effici5cy became app>5t :5 ! bact]ia 9 ! wat] 7 /udi$ 9 _! relations to disease1 & ,piefke sugge/$#bb t ! fir/ efflu5t aft] scrap+ %\ld be reject$ = "o day aft] ord9>y scrap+s & = "o week aft] replac+ ! s&4 ,9 a m rec5t pap]#bc he r$uces ^! e/imates to ! fir/ million gallons ( wat] p] acre filt]$ aft] scrap+ = op5 & twice z great a quantity = cov]$ filt]s1 & to six days aft] replac+ ! s&1 :i* la/ he e/imates w occur only once a ye>4 ,tak+ ! quantity ( wat] filt]$ betwe5 scrap+s at #ac4i million gallons p] acre1 ! quantity obs]v$ at ,/ralau 9 ! summ] ( #ahic1 he f9ds t x is necess>y to wa/e #i p] c5t ( ! total quantity ( efflu5t f op5 & #ac4h p] c5t ( t f cov]$ filt]s4 ,! elev5 ,g]man wat]-works#bd filt]+ riv]-wat]s1 h[ev]1 filt]$ on an av]age #ea4j in/ead ( #ac4i million gallons p] acre betwe5 scrap+s1 & apply+ ,piefke's figures to !m ! quantities ( wat] to be wa/$ w\ld be only ab\t "o f\r? ( 8 e/imates = ,/ralau4 ,! rules ( ! ,imp]ial ,bo>d ( ,heal?#be require t e ,g]man filt] %all be s con/ruct$ 8t :5 an inf]ior efflu5t results x c be disconnect$ f ! pure-wat] pipes & ! filtrate all[$ to be wa/$40 ,! dra9-pipe = remov+ ! reject$ wat] %\ld be connect$ bel[ ! app>atus = regulat+ ! rate & loss ( head1 s t ! filt] c be op]at$ exactly z usual1 & ! efflu5t c be turn$ back to ! pure-wat] pipes )\t /opp+ or *ang+ ! rate4 ,! works at ,b]l9 & at ,hamburg con=m to ?is requirem5t1 & mo/ ( ! old] ,g]man works h be5 or are be+ built ov] to make !m d s4 ,9 reg>d to ! ext5t ( det]ioration aft] scrap+1 ,piefke's exp]im5ts h always %[n mu* l>g] numb]s ( bact]ia bo? ( ! ord9>y =ms & ( special appli$ =ms on ! fir/ day aft] scrap+1 ! numb]s frequ5tly be+ _m times z high z at o!r times4 ,at ! ,lawr5ce ,exp]im5t ,/ation x 0 f\nd 9 #ahib t on an av]age ! numb] ( wat] bact]ia 0 increas$ by #gj p] c5t 7cont9u\s filt]s only7 = ! ?ree days foll[+ scrap+1 :ile ,b4 prodigiosus :5 appli$ 0 increas$ #adj p] c5t1 ! increase be+ mo/ m>k$ :]e ! dep? ( s& 0 lea/1 & ) ! highe/ rate ( filtration4 ,! same t5d5cy 0 f\nd 9 #ahic1 :5 ! increase 9 ! wat] bact]ia on ! fir/ day aft] scrap+ 0 only #ai p] c5t & ,b4 prodigiosus #fd p] c5t1 b = a portion ( ! ye> ! diff]5ce 0 great]1 av]ag+ #acb & #bfb p] c5t1 respectively4 ,^! diff]5ces are mu* less ?an ^? record$ by ,piefke1 & ) ! high effici5cies regul>ly obta9$ at ,lawr5ce !y w\ld h>dly ju/ify ! exp5sive practice ( wa/+ ! efflu5t4 ,! r$uction 9 effici5cy foll[+ scrap+ is mu* less at l[ rates1 & if a filt] is />t$ at mu* less ?an its normal rate aft] scrap+1 & !n gradually increas$ to ! /&>d aft] ! s$im5t lay] is =m$1 ! poor "w w be l>gely avoid$4 ,practically ?is is done at ,b]l9 & at ,hamburg4 ,! filt]s are />t$ at a f\r? or less ( ! usual rates & are gradually increas$1 z pa/ exp]i5ce ) bact]ial results has %[n x c be safely done1 & ! efflu5t is !n ev5 at fir/ s well purifi$ t x ne$ n be wa/$4 ,practically 9 build+ new filt]s ! provision ( a suitable connection = wa/+ ! efflu5ts into ! dra9 :i* is necess>y = empty+ !m involves no s]i\s exp5se & %\ld be provid$1 b x may be que/ion$ h[ (t5 x %\ld be us$ = wa/+ ! efflu5ts4 ,if ! raw wat] is s bad t a good efflu5t _c be obta9$ by c>eful manipulation ev5 j aft] scrap+1 ! c\rse ( ! ,b]l9 au?orities 9 clos+ ! ,/ralau works & seek+ a less pollut$ supply w\ld seem to be ! only really safe proc$ure4 ,,s&-,,wa%+4 ,illu/ration3 ,,clean+ ,a ,,filt]1 ,,ea/ ,,london4 ,illu/ration3 ,,wa%+ ,,dirty ,,s& ,,) ,,hose1 ,,antw]p4 ,to face page #gf4 ,! s&-wa%+ app>atus is an important "p ( mo/ ,european filt]+ plants4 ,x seldom happ5s t a natural s& c be f\nd clean en\gh & suffici5tly free f f9e p>ticles al?\gh su* a s& 0 f\nd & us$ = ! ,lawr5ce filt]4 ,mo/ ( ! s& 9 use = filtration 9 ,europe 0 orig9ally wa%$4 ,9 ! op]ation ( ! filt]s also1 s&-wa%+ is us$ = ! dirty s&1 :i* c !n be us$ ov] & ov] at a mu* l[] co/ ?an w\ld be ! case if fre% s& 0 us$ = refill+4 ,! me?ods us$ = wa%+ s& at ! diff]5t works pres5t a great v>iety bo? 9 _! details & 9 ! und]ly+ pr9ciples4 ,=m]ly boxes ) d\ble p]=at$ bottoms 9 :i* ! s& 0 plac$ & /irr$ by a man z wat] f bel[ rose ?r\gh !m1 & o!r simil> arrangem5ts 7 commonly us$1 b !y are at pres5t only reta9$1 s f> z ,i "k1 9 "s ( ! small] ,engli% works4 ,! cleans+ obta9$ is app>5tly consid]ably less ?or\gh ?an ) "s ( ! mod]n devices4 ,illu/ration3 ,,fig4 #ac4--;,,hose-,,wa%+ ,,= ,,dirty ,,s&4 ,hose-wa%+ is us$ 9 ,london by ! ,s\?w>k & ,vauxhall1 ,lambe? & ,*elsea companies1 & also at ,antw]p4 ,= ?is a plat=m is con/ruct$ ab\t #ae feet long by #h feet wide1 ) a pit* l5g?wise ( #f to #h in*es 7,fig4 #ac74 ,! plat=m is surr\nd$ by a wall ris+ f "o foot at ! bottom to ?ree feet high at ! top1 except ! l[] end1 :i* is clos$ by a removable plank weir #e or #f in*es high4 ,f two to f\r cubic y>ds ( ! s& are plac$ ^u ?is plat=m & a /ream ( wat] f a hose ) a #c_/d or #g_/h-;in* nozzle is play$ ^u x1 mov+ x ab\t f place to place4 ,! s& itself is always kept t[>d ! upp] end ( ! plat=m1 :ile ! wat] ) ! dirt remov$ fl[s d[n into ! pond made by ! weir1 :]e ! s& settles out & ! dirt ov]fl[s ) ! wat]4 ,:5 ! wat] comes (f cle>1 :i* is usually aft] an h\r or a little less1 ! weir is remov$1 &1 aft] dra9+1 ! s& is remov$4 ,^! arrangem5ts are built 9 pairs s t ! hose c be us$ 9 "o :ile ! s& is be+ *ang$ 9 ! o!r4 ,!y are usually built ( brick laid 9 cem5t1 b plank & iron are also us$4 ,! corn]s are sometimes c>ri$ out squ>e z 9 ! figure1 b are m (t5 r\nd$4 ,! wa%+ is app>5tly fairly well done4 ,9 ,g]many ! s-call$ 8drum0 wa%+-ma*9e1 draw+s ( :i* h be5 sev]al times publi%$1#bf has come to be almo/ univ]sally us$4 ,x consi/s ( a l>ge revolv+ cyl9d]1 on ! bottom ( ! inside ( :i* ! s& is sl[ly pu%$ up t[>d ! high] end by endless screw-blades atta*$ to ! cyl9d]1 :ile wat] is freely play$ ^u x all ! way4 ,! ma*9e requires a special h\se = its accommodation & f #b to #d horse-p[] = its op]ation4 ,x wa%es f #b4e to #d y>ds ( s& p] h\r mo/ ?or\ghly1 ) a consumption ( f #aa to #ad times z l>ge a volume ( wat]4 ,! app>atus is n pat5t$ or made = sale1 b full plans c be easily secur$4 ,a ma*9e made by ,samuel ,pegg ,sons1 ,leice/]1 ,eng41 pu%es ! s& up a slight incl9e d[n :i* wat] fl[s4 ,x is v heavy & requires p[] to op]ate x4 ,! pat5t has expir$4 ,a ma*9e mu* l x b light] & m conv5i5t & mov$ by wat]-p[] d]iv$ f ! wat] us$ = wa%+ in/ead ( /eam-p[] is us$ at ,zri* ) good results4 ,9 ,gre5way's ma*9e ! s& is =c$ by a screw ?r\gh a long n>r[ cyl9d] 9 :i* !re is a curr5t ( wat] 9 ! opposite direction4 ,! p[] requir$ is furni%$ by a wat]-motor1 z ) ! ma*9e at ,zri*4 ,! app>atus is m\nt$ on :eels & is portable2 x has an appliance = pil+ up ! wa%$ s& or load+ x onto c>s4 ,x is pat5t$ & is manufactur$ by ,james ,gibb ,co41 ,london4 ,sev]al ( ! ,london wat] companies are n[ us+ ejector wa%]s1 & su* an app>atus has be5 plac$ by ! side ( ! 8drum0 wa%]s at ,hamburg4 ,?is app>atus 0 made by ,krt+ ,bro!rs 9 ,hannov]1 & comb9es ! ejectors long made by t firm ) hopp]s f designs by ,mr4 ,bryan1 eng9e] ( ! ,ea/ ,london ,wat] ,company4 ,an app>atus diff]+ f ?is only 9 ! %ape ( ! ejectors & "s m9or details has be5 pat5t$ 9 ,engl&1 & is = sale by ,messrs4 ,hunt]1 ,fraz] ,goodman1 ,b[1 ,london4 ,bo? ( ^! =ms consi/ ( a s]ies ( conical hopp]s1 f ! bottom ( ea* ( :i* ! s& & wat] are =c$ into ! top ( ! next by means ( ejectors1 ! excess ( dirty wat] ov]fl[+ f ! top ( ea* hopp]4 ,! app>atus is compact & n likely to get out ( ord]1 b is n portable4 ,x c be easily arrang$ to take ! s& at ! level ( ! gr\nd1 or ev5 l[] if desir$1 & deliv] x wa%$ at "s little elevation1 ?us m9imiz+ h&-labor4 ,! wa%+ is regul> & ?or\gh4 ,! objection mo/ frequ5tly rais$ aga9/ its use is ! quantity ( wat] requir$1 b at ,hamburg ,i 0 in=m$ t ! volume ( wat] requir$ 0 only ab\t #ae times t ( ! s&1 :ile almo/ z mu* 7#ac-ad volumes7 7 requir$ = ! 8drum0 wa%]s1 & ! sav+ 9 p[] mu* m ?an (fset ! extra co/ = wat]4 ,9 addition to ! above processes ( s&-wa%+1 ,piefke's me?od ( clean+ )\t scrap+#bg might be m5tion$1 al?\gh z yet x has h>dly pass$ ! exp]im5tal /age1 & has only be5 us$ on extremely small filt]s4 ,! process consi/s ( /irr+ ! surface s& ( ! filt] ) 8waltz]s0 :ile a ?9 %eet ( wat] rapidly fl[s ov] ! surface4 ,?is arrangem5t necessitates a special con/ruction ( ! filt]s1 provid+ = rapidly remov+ ! unfilt]$ wat] f ! surface1 & = produc+ a regul> & rapid movem5t ( a ?9 %eet ( wat] ov] ! surface4 ,9 ! little filt]s n[ 9 use1 "o ( :i* ,i saw 9 a brew]y 9 ,b]l91 ! clean+ is rapidly1 *eaply1 & app>5tly well done4 ,9 wa%+ dirty s& x is obvi\s t any small s&-gra9s w be remov$ ) ! dirt1 & 9 wa%+ new s& ! ma9 object is to remove ! gra9s bel[ a c]ta9 size4 ,x is also app>5t t ! sizes ( gra9s :i* w & ^? :i* w n be remov$ are dep5d5t ^u ! me*anical arrangem5ts ( ! wa%]1 z1 = example1 ) ! ejectors1 ^u ! sizes ( ! hopp]s1 & ! quantity ( wat] pass+ ?r\gh !m1 & c>e %\ld be tak5 to make !m correspond ) ! size ( gra9 select$ = ! filt] s&4 ,?is c only be done by exp]im5t1 z no results are available on ?is po9t4 ,9 "s places filt]$ wat] is us$ = s&-wa%+1 al?\gh ?is seems q unnecess>y1 z ord9>y riv]-wat] answ]s v well4 ,x is1 h[ev]1 (t5 *eap]1 especially 9 small works1 to use ! filt]$ wat] f ! ma9s r ?an provide a sep>ate supply = ! wa%]s4 ,! quantity ( wat] requir$ = wa%+ may be e/imat$ at #ae times ! volume ( ! s& & ! s& z #j4jd p] c5t ( ! volume ( ! wat] filt]$ 7page #gd71 s t #j4f p] c5t ( ! total quantity ( wat] filt]$ w be requir$ = s&-wa%+4 ,! co/ ( s&-wa%+ 9 ,g]many ) ! 8drum0 wa%]s is said to be f #ad to #bj c5ts p] cubic y>d1 includ+ labor1 p[]1 & wat]4 ,9 ,am]ica ! wat] w\ld co/ no m1 b ! labor w\ld be p]haps twice z de>4 ,) an ejector app>atus ,i %\ld e/imate ! co/ ( wa%+ dirty s& z foll[s3 ,! s& w\ld be br\ght & dump$ ne> to ! wa%]1 & "o man c\ld easily fe$ x 91 z no lift+ is requir$4 ,two m5 w\ld probably be requir$ to %ovel ! wa%$ s& into b>r[s or c>ts ) ! pres5t arrangem5ts1 b ,i ?9k ) a little +5uity ?is h&l+ c\ld be made easi]4 ,,e/imat$ ,,co/ ,,( ,,op]at+ ,,ejector ,,wa%]s #i ,,h\rs4 ,wages ( #c m5 at #b4jj #f4jj #aaj1jjj gals1 wat] 7#ae times ! volume ( s&7 at #j4je a ?\s& gals4 #e4ej ----- ,total co/ ( wa%+ #cf cubic y>ds #aa4ej or #cb c5ts a cubic y>d4 ,! co/ ( wa%+ new s& might be some:at less4 ,! o!r co/s ( clean+ filt]s1 scrap+1 transport+1 & replac+ ! s& are mu* great] ?an ! wa%+ itself4 ,l9dley /ates t at ,w>saw #bi days' labor ( #aj h\rs = "o man are requir$ to scrape an acre ( filt] surface1 & f\r times z mu* = ! annual deep scrap+1 digg+ up1 & replac+ ! s&4 ,! fir/ exp5se occurs 9 g5]al mon?ly1 & ! second only once a ye>4 ,at o!r places :]e ,i h secur$ correspond+ data ! figures range f #ai to #dj days' labor to scrape "o acre1 & av]age ab\t ! same z ,l9dley e/imates4 ,"u "s conditions s&-wa%+ does n pay1 & 9 /ill o!rs x is almo/ impossible4 ,no app>atus has yet be5 devis$ :i* w wa% ! dirt out ( ! f9e dune-s&s us$ 9 ,holl& )\t wa%+ a l>ge "p ( ! s& itself away1 & 9 ^! works fre% s&1 :i* is available 9 unlimit$ quantities & close to ! works1 is always us$4 ,at ,breslau ! dirty s& is sold = build+ purposes = "o ?ird ( ! price paid = new s& dr$g$ f ! riv]1 deliv]$ at ! works1 & no s& is ev] wa%$4 ,budape/1 ,w>saw1 & ,rott]dam also use fre% riv]-s& )\t wa%+1 except a v crude wa%+ to remove clay at ,budape/4 ,,*apt] ,,vi4 ,,!ory ,,& ,,effici5cy ,,( ,,cont9u\s ,,filtration4 ,! fir/ filt]s = a public wat]-supply 7 built by ,james ,simpson1 eng9e] ( ! ,*elsea ,wat] ,company at ,london 9 #ahbi4 ,!y 7 app>5tly int5d$ to remove dirt f ! wat] 9 imitation ( natural processes1 & )\t any v cle> conception ( ei!r ! exact ext5t ( purification or ! way 9 :i* x 0 to be accompli%$4 ,! removal ( turbidity 0 ! mo/ obvi\s result1 & a cle> efflu5t 0 ! s+le te/ ( ! effici5cy ( filtration1 z x rema9s ! legal crit]ion ( ! "w ( ! ,london filt]s ev5 to-day1 not)/&+ ! discov]y & use ( o!r & m delicate te/s4 ,! inv5tion & use ( me?ods = det]m9+ ! organic matt]s 9 wat] by ,wanklyn & ,frankl&1 ab\t #ahgj1 l$ to ! discov]y t ! proportion ( organic matt]s remov$ by filtration 0 disappo9t+ly l[1 & z1 at ! "t1 & = _m ye>s aft]w>d1 an exagg]at$ importance 0 giv5 to ! m]e quantities ( organic matt]s 9 wat]1 x 0 conclud$ t filtration _h only a limit$ influ5ce ^u ! heal?fulness ( ! filt]$ wat]1 & t practically z mu* c>e mu/ be giv5 to secur+ an unpollut$ wat] z w\ld be ! case if x 7 deliv]$ direct )\t filtration4 ,?is !ory1 al?\gh n confirm$ by m rec5t inve/igation1 und\bt$ly has _h a good influ5ce ^u ! ,engli% works by caus+ ! selection ( raw wat]s free f excessive pollutions1 &1 9 cases l ! ,london supplies1 drawn f ! ,?ames & ! ,lea1 9 /imulat+ a mo/ jeal\s c>e ( ! wat]%$s & ! purification ( sewage by ! t[ns ^u !m4 ,x 0 only aft] ! discov]y ( ! bact]ia 9 wat] & _! relations to heal? t ! hyg5ic significance ( filtration comm5c$ to be really und]/ood4 ,inve/igations ( ! bact]ia 9 ! wat]s be=e & aft] filtration 7 c>ri$ out at ,b]l9 by ,plagge & ,proskau]1 at ,london by ,dr4 ,p]cy ,frankl&1 & also at ,zri*1 ,altona1 & on a small] scale at o!r places4 ,^! inve/igations %[$ t ! bact]ia 7 ma9ly remov$ by filtration1 ! numb]s 9 ! efflu5ts r>ely exce$+ two or ?ree p] c5t ( ^? 9 ! raw wat]4 ,?is gave a new aspect to ! problem4 ,x 0 fur!r obs]v$1 especially at ,b]l9 & ,zri*1 t ! numb]s ( bact]ia 9 efflu5ts 7 app>5tly q indep5d5t ( ! numb]s 9 ! raw wat]1 & ! !ory 0 =m$ t all ( ! bact]ia 7 /opp$ by ! filt]s1 & t ^? f\nd 9 ! efflu5ts 7 ! result ( contam9ation f ! air & ( gr[?s 9 ! und]dra9s4 ,! logical conclusion f ?is !ory 0 t filt]$ wat] 0 q suitable = dr9k+ reg>dless ( ! pollution ( its s\rce4 ,x 01 h[ev]1 f\nd t ! numb]s ( bact]ia 9 ! efflu5ts 7 high] imm$iately aft] scrap+ ?an at o!r times1 & x 0 conclud$ t be=e ! =mation ( ! s$im5t lay] "s bact]ia 7 able to pass ! s&1 & x 0 !re=e recomm5d$ t ! fir/ wat] filt]$ aft] scrap+ %\ld be reject$4 ,piefke at ,b]l9 gave ! subject c>eful /udy1 & came to ! conclusion t x 0 almo/ entirely ! s$im5t lay] :i* /opp$ ! bact]ia1 & t ! bact]ia !mselves 9 ! s$im5t lay] =m$ a slimy mass :i* completely int]cept$ ^? 9 ! pass+ wat]4 ,:5 ?is lay] 0 remov$ by scrap+1 ! action 0 /opp$ until a new crop ( bact]ia _h accumulat$4 ,9 support ( ?is idea he /at$ t he _h tak5 ord9>y good filt]-s& & kill$ ! bact]ia 9 x by heat+ x1 & t on pass+ wat] ?r\gh1 no purification 0 effect$--9 fact1 ! efflu5t conta9$ m bact]ia ?an ! raw wat]4 ,aft] a little1 bact]ia e/abli%$ !mselves 9 ! s&1 & !n ! usual purification 0 obta9$4 ,piefke conclud$ t ! action ( ! filt] 0 a biological "o2 t simple /ra9+ 0 q inadequate to produce ! results obta9$2 t ! action ( ! filt] 0 ma9ly conf9$ to ! s$im5t lay]1 & t ! dep? ( s& beyond ! slight dep? necess>y = ! support ( ?is lay] _h no appreciable influ5ce ^u ! results4 ,! effect ( ?is !ory is /ill se5 9 ! %all[ s& lay]s us$ at ,b]l9 & "s o!r ,g]man works1 al?\gh at ,london ! t5d5cy is r t[>d ?ick] s& lay]s4 ,piefke's d$uctions1 h[ev]1 are n entirely support$ by 8 data z we und]/& !m 9 ! light ( m rec5t inve/igation4 ,! exp]im5t ) /]iliz$ s& has be5 repeat$ly tri$ at ! ,lawr5ce ,exp]im5t ,/ation ) results :i* q agree ) ,piefke's1 b x has also be5 f\nd t ! high numb]s1 (t5 _m times z high z 9 ! raw wat]1 d n repres5t bact]ia :i* pass 9 ! ord9>y c\rse ( filtration1 b in/ead enorm\s gr[?s ( bact]ia ?r\gh\t ! s& support$ by ! cook$ organic matt] 9 x4 ,x has be5 repeat$ly f\nd t ord9>y s& q incapable ( support+ bact]ial gr[?s1 aft] heat+ to a temp]ature capable ( kill+ ! bact]ia w aft]w>ds furni% ! food = mo/ extraord9>y numb]s4 ,a filt] ( su* s& may /op ! bact]ia ( ! pass+ wat] q z effectually z any o!r filt]1 b if s1 ! fact _c be det]m9$ )\t rec\rse to special me?ods1 on acc\nt ( ! enorm\s numb]s ( bact]ia 9 ! s&1 a small "p ( :i* are c>ri$ =w>d by ! pass+ wat]1 & completely mask ! normal action ( ! filt]4 ,! !ory t all or practically all ( ! bact]ia are int]cept$ by ! s$im5t lay]1 & t ^? 9 ! efflu5t are ! result ( gr[?s 9 ! s& or und]dra9s1 receiv$ two h>d bl[s 9 #ahhi & #ahia1 :5 mild epidemics ( typhoid fev] foll[$ unusually high numb]s ( bact]ia 9 ! efflu5ts at ,altona & at ,/ralau 9 ,b]l91 ) good evid5ce 9 ea* case t ! fev] 0 directly due to ! wat]4 ,bo? ( ^! cases came dur+1 & z ! result (1 sev]e w9t] wea!r ) op5 filt]s & "u conditions :i* are n[ recogniz$ z extremely unfavorable = good filtration4 ,z a result ( ! fir/ ( ^! epidemics a s]ies ( exp]im5ts 7 made at ,/ralau by ,frnkel & ,piefke 9 #ahij4 ,small filt]s 7 con/ruct$1 & wat] pass$ exactly z 9 ! ord9>y filt]s4 ,bact]ia ( special k9ds n exi/+ 9 ! raw wat] or efflu5ts 7 !n appli$1 & ! pres5ce ( a v small fraction ( !m 9 ! efflu5ts demon/rat$ beyond a d\bt t !y _h pass$ ?r\gh ! filt]s "u ! ord9>y conditions ( filtration4 ,^! exp]im5ts 7 aft]w>ds repeat$ by ,piefke alone "u some:at diff]5t conditions ) simil> results4 ,! numb]s ( bact]ia pass+1 al?\gh l>ge en\gh to e/abli% ! po9t t "s d pass1 7 nev]!less 9 g5]al b a small fraction ( "o p] c5t ( ! _m ?\s&s appli$4 ,?is me?od ( te/+ ! effici5cy ( filt]s _h already be5 us$ q indep5d5tly by ,pr(4 ,s$gwick at ! ,lawr5ce ,exp]im5t ,/ation 9 connection ) ! purification ( sewage1 & has s9ce be5 ext5sively us$ !re = exp]im5ts ) wat]-filtration4 ,kmmel also f\nd at ,altona t :ile 9 ! regul> samples = bact]ial exam9ation1 all tak5 at ! same "t 9 ! day1 !re 0 no app>5t connection betwe5 ! numb]s ( bact]ia 9 ! raw wat] & efflu5ts1 by tak+ samples at frequ5t int]vals ?r\gh\t ! tw5ty-f\r h\rs1 z has be5 done 9 a m rec5t s]ies ( exp]im5ts1 & all[+ = ! "t requir$ = ! wat] to pass ! filt]s1 a well-m>k$ connection 0 f\nd to exi/ betwe5 ! numb]s ( bact]ia 9 ! raw wat] & 9 ! efflu5ts4 ,illu/ration3 ,,fig4 #ad4--,,%[+ ,,bact]ia ,,suppos$ ,,to ,,come ,,?r\gh ,,filt]s ,,& ,,f ,,! ,,und]dra9s4 ,! subject has m rec5tly be5 /udi$ 9 mu* detail at ! ,lawr5ce ,exp]im5t ,/ation1 & x n[ appe>s t ! bact]ia 9 ! efflu5t f a filt] are f two s\rces3 directly f ! filt]$ wat]1 & f ! l[] lay]s ( ! filt] & und]dra9s4 ,?us we may say3 ,bact]ia 9 efflu5t ,bact]ia f und]dra9s a_/#ajj bact]ia 9 raw wat]1 :]e a is ! p] c5t ( bact]ia actually pass+ ! filt]4 ,bo? ( ^! t]ms dep5d ^u a :ole s]ies ( complex & b imp]fectly und]/ood conditions4 ,9 g5]al ! bact]ia f ! und]dra9s are l[ 9 cold w9t] wea!r1 (t5 almo/ nil1 :ile at ,lawr5ce ) wat] temp]atures ( #gj to #ge degrees1 & ov]1 9 ,july & ,augu/1 ! numb]s f ?is s\rce may rea* #bjj or #cjj1 b = ! o!r t5 mon?s ( ! ye> r>ely exce$ #ej "u normal conditions4 ,9 summ] especially x seems to be great] at l[ ?an at high rates ( filtration 7al?\gh a high rate = a %ort "t only increases x71 & s v>ies 9 ! opposite way f ! numb]s actually pass+ ! filt]s4 ,?is subject is by no means cle>ly und]/ood2 x is difficult1 almo/ impossible1 to sep>ate ! numb]s ( bact]ia into ! two p>ts--^? :i* come directly ?r\gh & may be dang]\s1 & ^? :i* h o!r orig9s & are h>mless4 ,! sket*1 ,fig4 #ad1 is drawn to repres5t my idea ( ! way !y may be divid$4 ,x has no /ati/ical basis :atev]4 ,! light un%ad$ section %[s ! p]c5tage numb] ( bact]ia :i* ,i conceive to be com+ ?r\gh a filt] "u giv5 conditions at v>i\s rates ( filtration1 :ile ! %ad$ section above repres5ts ! bact]ia f o!r s\rces1 & ! upp] l9e repres5ts ! sum ( ! two1 or ! total numb] ( bact]ia 9 ! efflu5t4 ,! relative importance ( ! two p>ts w\ld probably v>y widely ) v>i\s conditions4 ,) ! conditions indicat$ by ! sket* ! numb] ( bact]ia 9 ! efflu5t is almo/ con/ant3 = a v>iation ( only f #a4d to #b4e p] c5t ( ! numb] appli$ = ! :ole range is n a wide fluctuation = bact]ial results1 b ! numb] 9 ! l[] & dang]\s section is always rapidly increas+ ) increas+ rate4 ,?is !ory ( filtration acc\nts = _m o!rwise p]plex+ facts4 ,! conclusion rea*$ at ,zri* & else:]e t ! effici5cy ( filtration is indep5d5t ( rate may be expla9$ 9 ?is way4 ,?is is especially probable at ,zri*1 :]e ! numb] ( bact]ia 9 ! raw wat] 0 only ab\t #bjj1 & an extremely l>ge proportion relatively w\ld h to pass to make a well-m>k$ impression ^u ! total numb] 9 ! efflu5t4 ,^! und]dra9 bact]ia are1 s f> z we "k1 entirely h>mless2 we are only int]e/$ 9 !m to det]m9e h[ f> !y are capable ( decreas+ ! app>5t effici5cy ( filtration bel[ ! actual effici5cy1 or ! p] c5t ( bact]ia really remov$ by ! filt]4 ,?is effici5cy is dep5d5t ^u a l>ge numb] ( conditions _m ( :i* h already be5 discuss$ 9 connection ) gra9-size ( filt] s&1 und]dra9s1 rate ( filtration1 loss ( head1 etc41 & a m]e ref]5ce to !m "h w suffice4 ,p]haps ! mo/ important s+le condition is ! rate1 ! numb]s ( bact]ia pass+ increase rapidly ) x4 ,next1 f9e s& & 9 mod]ately deep lay]s t5ds to give high effici5cy4 ,! influ5ce ( ! loss ( head1 (t5 m5tion$1 is n %[n to be important by ! ,lawr5ce results1 nor c ,i f9d satisfactory ,european results 9 support ( x4 ,uni=mity 9 ! rate ( filtration on all p>ts ( ! filt]+ area & a con/ant rate ?r\gh\t ! tw5ty-f\r h\rs are reg>d$ z ess5tial conditions = ! be/ results4 ,sev]e w9t] wea!r has indirectly1 by di/urb+ ! regul> action ( op5 filt]s1 an injuri\s influ5ce1 & has be5 ! cause ( mo/ ( ! cases :]e filt]$ wat]s h be5 kn[n to injure ! heal? ( ^? :o h drunk !m4 ,?is action is exclud$ 9 filt]s cov]$ ) masonry ar*es & soil1 & su* con/ruction is app>5tly necess>y = ! be/ results 9 places subject to cold w9t]s4 ,! effici5cy ( filtration "u v>i\s conditions has be5 /udi$ by a mo/ elaborate s]ies ( exp]im5ts at ,lawr5ce ) small filt]s to :i* wat] has be5 appli$ conta9+ a bact]ium 7,b4 prodigiosus7 :i* does n occur naturally 9 ?is c\ntry & is n capable ( gr[+ 9 ! filt]1 s t ! results %\ld repres5t only ! bact]ia com+ ?r\gh ! filt] & n include any additions f ! und]dra9s4 ,^! results1 :i* h be5 publi%$ 9 full 9 ! reports ( ! ,massa*usetts ,/ate ,bo>d ( ,heal?1 especially = ! ye>s #ahib & #ahic1 %[ t ! numb] ( bact]ia pass+ increases rapidly ) increas+ rate1 & sl[ly ) decreas+ s& ?ickness & increas$ size ( s&-gra94 ,assum+ t ! numb] ( bact]ia pass+ is express$ by ! =mula #a 7rate7#b effective size ( s& ,p] c5t bact]ia pass+ -- ---------------------------------------- ---------------------------------------- #b 7sqrt7?ickness ( ! s& 9 in*es77 :]e ! rate is express$ 9 million gallons p] acre daily1 & calculat+ by x ! numb]s ( bact]ia = ! sev5ty-?ree mon?s = :i* satisfactory data are available f #aa filt]s 9 #ahib & #ahic1 we f9d t ,9 #ad cases ! numb]s obs]v$ 7 #d to #i times z great z ! calculat$ numb]s2 ,9 #f cases !y 7 #b to #c times z great2 ,9 #ce cases !y 7 betwe5 #a_/b & #b times ! calculat$ numb]s4 ,9 #ag cases !y 7 #a_/b to #a_/c ( !m4 ,9 #aa cases !y 7 less ?an #a_/c ! calculat$ numb]s4 ,! agreem5t is only mod]ately good1 & 9 fact no su* =mula c\ld be expect$ to give m ?an v r\gh approximations1 because x does n take into consid]ation ! num]\s o!r elem5ts1 su* z uni=mity & regul>ity ( filtration1 ! influ5ce ( scrap+1 ! "* ( ! s$im5t 9 ! raw wat]1 etc41 :i* are kn[n to affect ! results4 ,p]haps ! mo/ m>k$ g5]al diff]5ce is ! t5d5cy ( new or fre%ly-fill$ filt]s to give high]1 & ( old & well-compact$ filt]s to give l[]1 results ?an ^? indicat$ by ! =mula4 ,comp>+ ?is =mula ) ,piefke's results giv5 9 8 8,neue ,ermittelung50#bh ! =mula gives 9 ! fir/ s]ies 7#j4cd mm4 s&1 #j4ej m4 ?ick1 & rate #ajj mm4 p] h\r71 #j4be p] c5t pass+1 :ile ! av]age numb] ( ,b4 violaci\s report$1 exclud+ ! fir/ day ( decreas$ effici5cy aft] scrap+1 0 #j4bf p] c5t4 ,9 ! second s]ies1 ) half z high a rate ! numb]s *eck$ exactly ! calculat$ #j4jf p] c5t4 ,9 o!r exp]im5ts1#bi h[ev]1 9 #ahic1 :5 ! calculat$ p] c5t 0 also #j4be1 only #j4jc1 #j4jd1 & #j4jg p] c5t 7 obs]v$ 9 ! efflu5ts4 ,comp>+ ! results f ! actual filt]s1 7:i* numb]s also include ! bact]ia f ! und]dra9s & %\ld !re=e be some:at high]7 ) ! numb]s calculat$ z pass+ ?r\gh1 ,i f9d t = ! #df days1 ,aug4 #bj to ,oct4 #d1 #ahic1 = :i* detail$ results ( ! ,/ralau works are giv5 by ,piefke1 ! av]age calculat$ numb] pass+ is #j4bj p] c5t1 :ile twice z _m 7 obs]v$ 9 ! efflu5ts2 al?\gh ?ree ( ! filt]s gave bett] efflu5ts ?an ! o!r eight1 & ! numb]s f !m approximat$ closely ! calculat$ numb]s4 ,if we calculate ! p]c5tages ( bact]ia pass+ a numb] ( filt]s1 us+ ! maximum rate ( filtration all[$ = ! ,g]man filt]s :]e ?is is accurately det]m9$1 & = ! ,engli% filt]s tak+ ! maximum rate at "o & "o-half times ! rate obta9$ by divid+ ! daily quantity by ! area ( filt]s actually 9 use1 we obta93 ---------------------------------------- ------------------------ ,av]age ,effective ,maximum ,p] c5t ,dep? ( ,size ( ,rate ( ,bact]ia ,s&1 ,s&- ,filtration4 pass+ ,in*es4 gra94 #a r#b;d - ---------- #b sqrts& ---------------------------------------- ------------------------ ,hamburg #cb #j4ca #a4fj #j4jg ,altona #bh #j4cd #b4eg #j4ba ,b]l91 ,/ralau #bj #j4cd #b4eg #j4be ,b]l91 ,mggel #bj #j4cd #b4eg #j4be ,b]l91 ,tegel #bj #j4cg #b4eg #j4bg ,london1 ,s\?w>k ,vauxhall #cf #j4cd #b4ha #j4bb ,london1 ,we/ ,middlesex #ci #j4cg #b4ha #j4bc ,london1 ,*elsea #ed #j4cf #c4bg #j4bf ,london1 ,gr& ,junction #cj #j4dj #c4bg #j4ci ,london1 ,lambe? #cf #j4cf #c4ge #j4db ,middlesbor\gh #bj #j4db #e4he #a4eh ,zri* #bf #j4ce #g4ej #a4ij ---------------------------------------- ------------------------ ,! numb]s actually obs]v$ are 9 e case high] ?an ! calculat$ p] c5ts pass+1 z inde$ !y %\ld be on acc\nt ( ^? com+ f ! und]dra9s1 accid5tal contam9ation ( ! samples1 etc4 ,x may be said t filtration n[ practis$ 9 ,european works "u ord9>y conditions nev] all[s ov] #a or #b p] c5t bact]ia ( ! raw wat] to pass1 & ord9>ily n ov] "o f\r? to "o half ( "o p] c5t1 al?\gh exact data _c be obta9$ ow+ to mask+ effect ( ! bact]ia :i* come f bel[ & :i* be> no relation to ^? ( ! raw wat]4 ,by increas+ ! size ( ! filt]s1 f95ess & dep? ( s& 7z at ,hamburg71 ! effici5cy c be mat]ially increas$ above ^! figures4 ,at ! same "t x mu/ be borne 9 m9d t ! effectiv5ess ( a filt] may be greatly impair$ by inadequate und]dra9+1 by fluctuat+ rates ( filtration :]e ^! are all[$1 by freez+ 9 w9t] 9 ! case ( op5 filt]s 9 cold climates1 & by o!r irregul>ities1 all ( :i* c be prev5t$ by c>eful att5tion to ! respective po9ts4 ,! action ( a cont9u\s filt] ?r\gh\t is ma9ly t ( an exce$+ly f9e /ra9]1 & l a /ra9] is ma9ly conf9$ to ! susp5d$ or insoluble matt]s 9 ! raw wat]4 ,! turbidity1 s$im5t1 & bact]ia ( ! raw wat] are l>gely or entirely remov$1 :ile h>dness1 organic matt]1 & color1 s f> z !y are 9 solution1 are remov$ to only a slight ext5t1 if at all4 ,h>dness c be remov$ by ! addition ( lime 9 c>efully det]m9$ quantity be=e filtration 7,cl>k's process71 by means ( :i* ! excess ( c>bonic acid 9 ! wat] is absorb$ & ! lime add$1 toge!r ) t previ\sly 9 ! wat]1 is precipitat$4 ,ord9>y filtration w remove f "o f\r? to "o ?ird ( ! yell[-br[n color ( peaty wat]4 ,a l>g] proportion c be remov$ by ! addition ( alum1 :i* by decompos+ =ms an insoluble comp\nd ( alum9a ) ! color+ matt]1 :ile ! acid ( ! alum goes into ! efflu5t ei!r z free acid1 or 9 comb9ation ) ! lime or o!r base 9 ! wat]1 accord+ to _! respective quantities4 ,fre%ly precipitat$ alum9a c be sub/itut$ = ! alum at increas$ exp5se & tr\ble1 & t5ds to remove ! color )\t add+ acid to ! wat]4 ,^! w be discuss$ m 9 detail 9 connection ) me*anical filt]s4 ,alum is b r>ely us$ 9 sl[ s& filtration1 ! mo/ important works :]e x is us$ be+ 9 ,holl& ) peaty wat]s4 ,aft] all1 ! mo/ conclusive te/ ( ! effici5cy ( filtration is ! heal?fulness ( ! p :o dr9k ! filt]$ wat]2 & ! fact t _m ,european cities take wat]-supplies f s\rces :i* w\ld n be consid]$ fit = use 9 ! ,unit$ ,/ates &1 aft] filt]+ !m1 deliv] !m to populations hav+ dea?-rates f wat]-c>ri$ diseases :i* are s l[ z to be ! objects ( our admiration1 is ! be/ pro( ( ! effici5cy ( c>efully conduct$ filtration4 ,x is only necess>y to ref] to ,london1 draw+ its wat] f ! two small & pollut$ riv]s1 ! ,?ames & ! ,lea2 to ,altona1 draw+ its wat] f ! ,elbe1 pollut$ by ! sewage ( #f1jjj1jjj p1 #gjj1jjj ( !m )9 t5 miles above ! intakes2 to ,b]l91 us+ ! wat]s ( ! ,havel & ! ,spree2 to ,breslau1 tak+ its wat] f ! ,od] *>g$ ) ! sewage ( m9+ di/ricts 9 ,silicia & ,galicia1 :]e *ol]a is s common2 to ,lawr5ce1 ) its greatly decreas$ dea?-rate s9ce x has _h filt]$ wat]1 & to ! hundr$ o!r places :i* protect !mselves f ! infecti\s matt]s 9 _! raw wat]s by means ( filtration4 ,a few ( ^! cases are describ$ m 9 detail 9 ,app5dices ,v to ,,ix1 & _m o!rs 9 ! lit]ature m5tion$ 9 ,app5dix ,x4 ,an adequate pres5tation ( ev5 ^? data :i* h be5 already work$ up & publi%$ w\ld occupy too mu* space4 ,i ?9k e "o :o has c>efully /udi$ ! rec5t hi/ory ( wat] filtration 9 its relation to disease has be5 conv9c$ t filtration c>efully execut$ "u suitable & normal conditions1 ev5 if n an absolute1 is at lea/ a v sub/antial protection aga9/ wat]-c>ri$ diseases1 & ! few app>5t failures to remove objectionable qualities h be5 )\t exception due to abnormal conditions :i* are n[ und]/ood & 9 future c be prev5t$4 ,,bact]ial ,,exam9ation ,,( ,,wat]s4 ,e l>ge filt]-plant %\ld h arrangem5ts = ! sy/ematic bact]ial exam9ation ( ! wat] be=e & aft] filtration1 especially :]e ! raw wat] is subject to s]i\s pollution4 ,su* exam9ations ne$ n be excessively exp5sive1 & !y w n only %[ ! effici5cy ( ! plant z a :ole1 b may be made to %[ ! relative effici5cies ( ! sep>ate filt]s1 ! relative effici5cies at diff]5t p>ts ( ! p]iods ( op]ation1 ! effect ( cold wea!r1 etc41 & w !n be a sub/antial aid to ! sup]9t5d5t 9 always secur+ good efflu5ts at ! m9imum co/4 ,9 addition a complete record ( ! bact]ia 9 ! wat] at diff]5t times may aid 9 det]m9+ def9itely :e!r ! wat] 0 connect$ ) outbreaks ( disease4 ,?us if an outbreak ( disease ( any k9d 7 prec$$ at a c]ta9 int]val by a great increase 9 ! numb] ( bact]ia1--z has be5 ! case1 = example1 ) ! typhoid epidemics at ,altona & ,b]l9 7see ,app5dices ,,ii & ,,vii71--a presumption w\ld arise t !y might h be5 connect$ ) ea* o!r1 & ea* "t x 0 repeat$ ! presumption w\ld be /r5g!n$1 :ile1 on ! o!r h&1 outbreaks occurr+ :ile ! bact]ia rema9$ con/antly l[ w\ld t5d to discr$it su* a !ory4 ,bact]ial inve/igations inaugurat$ aft] an epidemic is recogniz$1 z has frequ5tly be5 done1 seldom lead to results ( value1 bo? because ! local normal bact]ial conditions are g5]ally unkn[n at ! comm5cem5t ( ! inve/igation1 & because ! mo/ important "t1 ! "t ( infection1 is already long pa/ be=e ! fir/ samples are tak54 ,! fact t su* sporadic activities h l$ to few def9ite results %\ld ?r[ no discr$it ^u cont9u$ obs]vations1 :i* h repeat$ly prov$ ( ine/imable value4 ,consid]able misconception ( ! use ( bact]ial exam9ations exi/s4 ,! simple bact]ial c\nt ord9>ily us$1 & ( :i* ,i am n[ speak+1 does n & _c %[ :e!r a wat] conta9s disease-g]ms or n4 ,i object to ! ,*icago wat]1 n s mu* because a glass ( x conta9s a hundr$ ?\s& bact]ia m or less1 z because ,i am conv9c$1 by a /udy ( its s\rce 9 connection ) ! city's dea?-rate1 t x actually c>ries disease-g]ms :i* prove injuri\s to ?\s&s ( ^? :o dr9k x4 ,n[ ! fact be+ admitt$ t ! wat] is injuri\s to heal?1 v>iations 9 ! numb]s ( bact]ia 9 ! wat] drawn f diff]5t intakes & at diff]5t times probably correspond r\ghly ) v>y+ proportions ( fre% sewage1 & indicate r\ghly ! relative dang]s f ! use ( ! respective wat]s4 ,if filt]s %\ld be introduc$1 ! numb]s ( bact]ia 9 ! efflu5ts "u v>i\s conditions w\ld be an index ( ! respective effici5cies ( filtration1 & w\ld s]ve to detect poor "w1 & w\ld probably sugge/ ! measures necess>y = bett] results4 ,i w\ld sugge/ ! desirability ( su* inve/igations :]e me*anical filt]s are us$1 q z mu* z 9 connection ) sl[ filtration2 & x w\ld also be mo/ desirable 9 ! case ( _m wat]-supplies :i* are n filt]$ at all4 ,su* cont9u$ obs]vations h be5 made at ,b]l9 s9ce #ahhd2 at ,london s9ce #ahhf2 at ,bo/on & ,lawr5ce s9ce #ahhh2 & rec5tly at a l>ge numb] ( places1 includ+ ,*icago1 :]e obs]vations by ! city 7 comm5c$ 9 #ahid4 ,!y are n[ requir$ by ! ,g]man ,gov]nm5t 9 ! case ( all filt]$ public wat]-supplies 9 ,g]many1 )\t reg>d to ! s\rce ( ! raw wat]4 ,! ,g]man /&>d requires t ! efflu5t f ea* s+le filt]1 z well z ! mix$ efflu5t & raw wat]1 %all be exam9$ daily1 mak+ at "s works #aj to #cj samples daily4 ,?is am\nt ( "w1 h[ev]1 c usually be done by a s+le man2 & :5 a laboratory is once />t$1 ! co/ ( exam9+ #bj samples a day w n be mu* great] ?an if only #bj a week are tak54 ,9 ,engl& & at "s ( ! ,cont95tal works draw+ _! wat]s f b slightly pollut$ s\rces1 mu* small] numb]s ( samples are exam9$4 ,! "q :e!r ! exam9ations %\ld be made "u ! direction ( ! wat]-works company or dep>tm5t1 or by an indep5d5t body--z1 = in/ance1 by ! ,bo>d ( ,heal?--w dep5d ^u local conditions4 ,! =m] arrangem5t gives ! sup]9t5d5t ( ! filt]s ! be/ *ance to /udy _! action1 z he c himself control ! collection ( samples 9 connection ) ! op]ation ( ! filt]s1 & arrange !m to ?r[ light ^u ! po9ts he wi%es to inve/igate2 :ile exam9ation by a sep>ate au?ority af=ds p]haps great] protection aga9/ ! possible c>elessness or di%one/y ( wat]-works (ficials4 ,an arrangem5t be+ adopt$ 9 _m cases 9 ,g]many is to h a bact]ial laboratory at ! works :i* is "u ! control ( ! sup]9t5d5t1 & 9 :i* ! v num]\s compulsory obs]vations are made1 :ile ! ,bo>d ( ,heal? causes to be exam9$ f "t to "t by its own repres5tatives1 :o h no connection ) ! wat]-works1 samples tak5 to *eck ! wat]-works figures1 z well z to %[ ! "* ( ! wat] deliv]$4 ,x seems q desirable to h a man ^: pr9cipal bus9ess is to make ^! exam9ations2 z 9 case he also has num]\s o!r duties1 ! exam9ations may be f\nd to h be5 neglect$ at "s "t :5 !y are mo/ want$4 ,su* a man %\ld h _h ?or\gh tra9+ 9 ! pr9ciples ( bact]ial manipulation1 b x is q unnecess>y t he %\ld be an exp]t bact]iologi/1 especially if a compet5t bact]iologi/ is reta9$ = consultation 9 cases ( d\bt or difficulty4 ,,*apt] ,,vii4 ,,int]mitt5t ,,filtration4 ,by int]mitt5t nitration is und]/ood t filtration 9 :i* ! filt]+ mat]ial is sy/ematically & adequately v5tilat$1 & :]e ! wat] dur+ ! c\rse ( filtration is br\ght 9 contact ) air 9 ! pores ( ! s&4 ,9 cont9u\s filtration1 :i* alone has be5 previ\sly consid]$1 ! air is driv5 out ( ! s& z completely z possible be=e ! comm5cem5t ( filtration1 & ! s& is kept cont9u\sly cov]$ ) wat] until ! s& becomes clogg$ & a dra9+1 ) an incid5tal a]ation1 is necess>y to all[ ! filt] to be scrap$ & aga9 put 9 s]vice4 ,9 int]mitt5t filtration1 on ! o!r h&1 wat] is tak5 ov] ! top ( ! dra9$ s& & settles into x1 com+ 9 contact ) ! air 9 ! pores ( ! s&1 & passes freely ?r\gh to ! bottom :5 ! wat]-level is kept well d[n4 ,aft] a limit$ "t ! application ( wat] is /opp$1 & ! filt] is all[$ to aga9 dra9 & become ?or\ghly a]at$ prep>atory to receiv+ ano!r dose ( wat]4 ,?is sy/em ( treat+ wat] 0 sugge/$ by ! unequall$ purification ( sewage effect$ by a simil> treatm5t4 ,x has be5 inve/igat$ at ! ,lawr5ce ,exp]im5t ,/ation1 & appli$ to ! con/ruction ( a filt] = ! city ( ,lawr5ce1 bo? ( :i* are due to ! indefatigable en]gy ( ,hiram ,f4 ,mills1 ,c4,e4 ,9 its op]ation int]mitt5t diff]s f cont9u\s filtration 9 t ! /ra9+ action is less p]fect1 because ! filt]s yield no wat] :ile be+ a]at$1 & mu/ !re=e filt] at a great] velocity :5 9 use to yield ! same quantity ( wat] 9 a giv5 "t1 & also on acc\nt ( ! me*anical di/urbance :i* is almo/ inv>iably caus$ by ! application ( ! wat]2 b1 on ! o!r h&1 ! oxidiz+ p[]s ( ! filt]1 or ! t5d5cy to nitrify & de/roy ! organic matt]s1 are /rong]1 & 9 addition1 if ! rate is n too high1 ! bact]ia die m rapidly 9 ! ?or\ghly a]at$ s& ?an is ! case ) ord9>y filt]s4 ,x 0 f\nd at ,lawr5ce 9 connection ) sewage filt]s t :5 nitrification 0 actively tak+ place ! numb]s ( bact]ia 7 mu* l[] ?an "u opposite conditions1 & x 0 ?\ght t nitrification 9 itself might cause ! dea? ( ! bact]ia4 ,lat] exp]im5ts1 h[ev]1 ) pure cultures ( bact]ia ( v>i\s k9ds appli$ to int]mitt5t filt]s ) wat] to :i* ammonia & salts suitable = nitrification 7 add$1 %[$ t bact]ia ( all ! species tri$ 7 able to pass ! filt] 9 ! pres5ce ( nitrification1 produc+ at lea/ "o ?\s& times z mu* nitrates z c\ld result 9 any case ( wat]-filtration1 z freely z 0 ! case :5 ! ammonia 0 n add$ & !re 0 b little nitrification4 ,^! results %[$ conclusively t nitrification 9 itself is n an important factor 9 bact]ial removal1 al?\gh nitrification & bact]ial purification d to "s ext5t g toge!r2 p]haps 9 "p because ! nitrification de/roys ! food ( ! bact]ia & s />ves !m out1 b probably mu* m because ! conditions ( a]ation1 temp]ature1 etc41 :i* favor nitrification also favor equally1 & ev5 9 its abs5ce1 ! dea? ( ! bact]ia4 ,! rate at :i* wat] mu/ pass ?r\gh an int]mitt5t filt] is1 on acc\nt ( ! int]vals ( re/1 consid]ably great] ?an t requir$ to give a correspond+ total yield f a cont9u\s filt]1 & its /ra9+ effect is r$uc$ to an ext5t comp>able to ?is increase 9 rate2 & if o!r conditions did n come 91 ! bact]ial effici5cy ( an int]mitt5t filt] w\ld rema9 bel[ t ( a cont9u\s "o4 ,z a matt] ( fact ! bact]ial effici5cy has usually be5 f\nd to be less ) int]mitt5t filt]s at ! ,lawr5ce ,exp]im5t ,/ation1 :5 !y h be5 run at rates su* z are commonly us$ = cont9u\s filt]s 9 ,europe1 say f "o & "o half to two million gallons & upw>ds p] acre daily4 ,) l[] rates1 & especially ) r f9e mat]ials1 ! bact]ial effici5cy is mu* great]2 b x may be d\bt$ :e!r x w\ld ev] be great] ?an t ( a cont9u\s filt] ) ! same filt]+ mat]ial & ! same total yield p] acre4 ,! numb] ( bact]ia com+ f ! und]dra9s is app>5tly g5]ally less1 & ) v high summ] temp]atures mu* less1 ?an 9 cont9u\s filt]s1 & ?is (t5 gives an app>5t bact]ial sup]iority to ! int]mitt5t filt]s4 ,! efflu5ts f int]mitt5t (t5 conta9 less slightly organic matt] ?an ^? f cont9u\s filt]s2 b1 on ! o!r h&1 h>dly any wat] propos$ = a public wat]-supply has organic matt] en\gh to be ( any sanit>y significance :atev]1 ap>t f ! liv+ bodies :i* (t5 accompany x2 & if ! latt] are remov$ by /ra9+ or o!rwise1 we c safely disreg>d ! organic matt]s4 ,9 addition1 ! wat] filt]$ w 9 a great majority ( cases h en\gh air dissolv$ 9 itself to produce :atev] oxidation !re is "t = 9 ! few h\rs requir$ = x to pass ! filt]1 & x is only at v l[ rates ( filtration t int]mitt5t filt]s produce efflu5ts ( great] *emical purity ?an by ! ord9>y process4 ,! yell[-br[n color+ matt] pres5t 9 s _m wat]s appe>s to be q incapable ( rapid nitrification2 & :]e x is to "s ext5t remov$ by filtration1 ! action is dep5d5t ^u o!r & b imp]fectly und]/ood causes :i* seem to act equally 9 cont9u\s & int]mitt5t filt]s4 ,! peculi>ities ( con/ruction involv$ by ?is me?od ( filtration w be be/ illu/rat$ by a discussion ( ! ,lawr5ce city filt] design$ by ,hiram ,f4 ,mills1 ,c4,e41 :i* is ! only filt] 9 exi/5ce ^u ?is plan4#cj ,,! ,,lawr5ce ,,filt]4 ,! filt] consi/s ( a s+le b$ #b-a_/b acres 9 area1 ! bottom ( :i* is #g feet bel[ l[ wat] 9 ! riv]1 & fill$ ) gravel & s& to an av]age dep? ( #d-a_/b feet4 ,! filt] is all 9 a s+le b$ in/ead ( be+ divid$ into ! ?ree or f\r sections :i* w\ld probably h be5 us$ = a cont9u\s filt] ( ?is size4 ,! wat]-tight bottom also 0 disp5s$ )1 & ! gravel 0 prev5t$ f s9k+ into ! silt by ?9 int]m$iate lay]s ( grad$ mat]ials4 ,! sav+ 9 co/ 0 consid]able2 b1 on ! o!r h&1 a consid]able quantity ( gr\nd-wat] comes up ?r\gh ! bottom & increases ! h>dness ( ! wat] f #a4e to #b4f p>ts ( calcium c>bonate 9 #ajj1jjj2 & :ile ! wat] :5 comp>$ ) _m o!r wat]s is /ill extremely s(t1 ! addition _c be reg>d$ z desirable4 ,! gr\nd-wat] also conta9s iron1 :i* increases ! color ( ! wat] above :at x w\ld o!rwise be4 ,! und]dra9s h a frictional resi/ance t5 times z great z w\ld be desirable = a cont9u\s filt]1 ! idea be+ to *eck extreme rates ( filtration 9 case ( unequal flood+1 & also to limit ! quantity ( wat] :i* c\ld be gott5 ?r\gh ! filt] to t correspond+ to a mod]ate rate ( filtration4 ,! s&1 in/ead ( be+ all ( ! same-siz$ gra91 is ( two grades1 ) effective sizes respectively #j4be & #j4cj mm41 ! co>s] s& be+ plac$ f>!/ away f ! und]dra9s1 :]e its great] di/ance is int5d$ to balance its r$uc$ frictional resi/ance & make all p>ts filt] at an equal rate4 ,! surface in/ead ( be+ level is wav$1 t is1 !re are ridges ?irty feet ap>t1 slop+ ev5ly to ! valleys "o foot deep half way betwe5 !m1 to all[ wat] to be br\ght on rapidly )\t di/urb+ ! s& surface4 ,= ! same reason1 z well z to secure equality ( di/ribution1 a sy/em ( concrete c>ri]s = ! raw wat] goes to all p>ts ( ! filt]1 r$uc+ ! effective filt]+ area by #d or #e p] c5t4 ,! filt] is scrap$ z necess>y 9 sections1 ! "w be+ p]=m$ :5 ! filt] is hav+ its daily re/ & a]ation4 ,ow+ to ! diff]5ce 9 frictional resi/ance be=e & aft] scrap+1 & to ! fact t x is impossible to scrape ! entire area 9 "o day1 consid]able v>iations 9 ! rate ( filtration 9 diff]5t p>ts ( ! filt] mu/ occur4 ,! heavy frictional resi/ance ( ! und]dra9s :5 m ?an ! prop] quantity ( wat] passes !m t5ds to correct ?is t5d5cy especially = ! m remote p>ts ( ! filt]1 b p]haps at ! exp5se ( ^? ne> to ! ma9 dra94 ,! filt] is n cov]$ z ! sugge/ions 9 ,*apt] ,,ii w\ld require1 b ?is is h>dly on acc\nt ( its be+ an int]mitt5t filt]4 ,! annual report ( ! ,massa*usetts ,/ate ,bo>d ( ,heal? = #ahic /ates t dur+ ! fir/ half ( ,decemb]1 #ahic1 ! surface rema9$ cov]$1 t is1 x 0 us$ cont9u\sly1 & aft] ,decemb] #af? x 0 s us$ :5 ! temp]ature 0 bel[ #bd1 & 0 dra9$ only :5 ! temp]ature 0 #bd or above4 ,! days on :i* ! filt] 0 dra9$ dur+ ! rema9d] ( ,decemb] are n giv51 b dur+ ,janu>y & ,febru>y1 #ahid1 ! filt] rema9$ cov]$ #bi days & 0 dra9$ #cj days4 ,bact]ial samples 7 tak5 on #dd ( ^! days1 #bb days :5 x 0 dra9$ & #bb :5 x 0 n4 ,! av]age numb] ( bact]ia on ! days :5 x 0 n dra9$ 0 #acg & on ^? days :5 x 0 dra9$ #beb p] cubic c5timet]4 ,f ,febru>y #bd? to ,m>* #ab? ! numb] ( bact]ia 7 unusually high1 av]ag+ #dib p] cubic c5timet]1 or #e4bh p] c5t ( ! #icjh appli$4 ,dur+ ?is p]iod ! filt] 0 us$ int]mitt5tly2 !re 0 ice ^u x1 & p>ts ( ! surface 7 scrap$ "u ! ice1 & high rates ( filtration und\bt$ly result$ on ! scrap$ areas4 ,aft] ,m>* #ab? ! ice _h disappe>$ & v mu* bett] results 7 obta9$4 ,:ile !re may be "s "q z to ! direct cause ( ?is decreas$ effici5cy ) cont9u$ cold wea!r & ice1 ! results c]ta9ly are n su* z to %[ ! advisability ( build+ op5 filt]s 9 ! ,lawr5ce climate4 ,! co/ ( build+ ! filt] 9 comp>ison ) ,european filt]s 0 extraord9>ily l[--only #fg1jjj1 or #bg1jjj p] acre ( filt] surface4 ,to h con/ruct$ op5 cont9u\s filt]s ( ! same area ) wat]-tight bottoms1 divid$ into sections ) sep>ate dra9s & regulat+ app>atus1 ) ! necess>y pip+1 w\ld h co/ at lea/ half z mu* m1 & ) ! masonry cov] :i* ,i reg>d z mo/ desirable 9 ! ,lawr5ce climate ! co/ w\ld h be5 two or ?ree times ! exp5diture actually requir$4 ,x 0 no easy matt] to secure ! cons5t ( ! city gov]nm5t to ! exp5diture ( ev5 ! sum us$2 !re 0 mu* skepticism z to ! process ( filtration 9 g5]al1 & x 0 said t me*anical filt]s c\ld be put 9 = ab\t ! same co/4 ,insi/+ ^u ! m complete & exp5sive =m might h result$ ei!r 9 an indef9ite po/ponem5t ( action1 or 9 ! adoption ( an inf]ior & entirely inadequate process4 ,/ill ,i feel /rongly t 9 ! end ! great] exp5se w\ld h prov$ an excell5t inve/m5t 9 secur+ s(t] wat] & 9 ! great] facility & security ( op]at+ ! filt] 9 w9t]4 ,9 reg>d to ! effect ( ! ,lawr5ce filt] ^u ! heal? ( ! city1 ,i c be/ quote f ,mr4 ,mills' pap] 9 ! ,report ( ! ,massa*usetts ,/ate ,bo>d ( ,heal? = #ahic1 & also publi%$ 9 ! ,j\rnal ( ! ,new ,engl& ,wat]-works ,association4 ,mr4 ,mills says3 8,9 ! foll[+ diagram ,fig4 #ae ! av]age numb] ( dea?s f typhoid fev] at ,lawr5ce = ea* mon? f ,octob] to ,may1 9 ! prec$+ five ye>s1 are giv5 by ! heavy dott$ l9e2 & ! numb] dur+ ! pa/ eight mon?s are giv5 by ! heavy full l9e4 8,! total numb] = eight mon?s 9 pa/ ye>s has be5 =ty-?ree1 & 9 ! pres5t ye> sev5te51 mak+ a sav+ ( tw5ty-six4 ,( ! sev5te5 :o di$ n9e 7 op]atives 9 ! mills1 ea* ( :om 0 kn[n to h drunk unfilt]$ canal wat]1 :i* is us$ 9 ! factories at ! s9ks = wa%+4 ,illu/ration3 ,,fig4 #ae4--,,typhoid ,,fev] ,,9 ,,lawr5ce4 8,! f9] full l9e %[s ! numb] ( ^? :o di$ mon? aft] mon? :o are n kn[n to h us$ ! poison$ canal wat]4 ,! :ole numb] 9 ! eight mon?s is eight4 8,x is evid5t f ! previ\s diagram n reproduc$ t ! numb]s above ! f9e full l9e1 "h1 foll[ aft] ^? at ,l[ell 9 ! usual "t1 & 7 und\bt$ly caus$ by ! sickness at ,l[ell2 b we h satisfactory reason to conclude t ! disease 0 n propagat$ ?r\gh ! filt] b t ! g]ms 7 convey$ directly into ! canals & to ^? :o drank ( ! unfilt]$ canal wat]4 ,among ! op]atives ( "o ( ! l>ge corporations n us+ ! canal wat] !re 0 n a case ( typhoid fev] dur+ ?is p]iod4 ,w>n+s h be5 plac$ 9 ! mills :]e canal wat] is us$ to prev5t ! op]atives f dr9k+ x4 8,we f9d1 !n1 t ! mortality f typhoid fev] has1 dur+ ! use ( ! filt]1 be5 r$uc$ to #dj p] c5t ( ! =m] mortality1 & t ! cases =m+ ne>ly "o half ( ?is #dj p] c5t 7 und\bt$ly due to ! cont9u$ use ( unfilt]$ riv] wat] drawn f ! canals40 ,! records ( typhoid fev] 9 ,lawr5ce be=e & aft] ! introduction ( filt]s are z foll[s3 ,,dea?s ,,f ,,typhoid ,,fev] ,,9 ,,lawr5ce1 #ahhh-ih4 ---------------------------------------- --------------------------- ,p]sons :o are kn[n to h be5 ,ye>s4 ,total ,dea?s expos$ to infection4 ,numb] p] ----------------------------------- ( #aj1jjj ,:ile liv+ out ,dea?s4 ( ,by dr9k+ ( t[n j be=e ,population4 ,canal ,wat]4 fall+ sick 9 ,lawr5ce4 ---------------------------------------- -------------------------- #ahhh #dh #aa4cf #ahhi #ee #ab4ff #ahij #fj #ac4dd #ahia #ee #aa4id #ahib #ej #aj4eb #ahic #ci #g4if #ahid #bd #d4ge #ab #ahie #af #c4jg #i #b #ahif #aj #a4hf #b #d #ahig #i #a4fb #ahih #h #a4ci #a ---------------------------------------- -------------------------- ,filt] put 9 op]ation ,septemb]1 #ahic4 ,av]age rate be=e ! introduction ( filt]$ wat] 7#ahhh-ib7 #aa4ca ,av]age rate aft]w>d 7#ahid-ih7 #b4ed ,^! results %[ a /rik+ r$uction 9 ! dea?s f typhoid fev] ) ! introduction ( filt]$ wat]1 :i* has be5 mo/ gratify+ 9 e way4 ,! m rec5t hi/ory ( ! und]dra9s ( ! ,lawr5ce filt] is p>ticul>ly in/ructive4 ,ow+ to ! abs5ce ( a wat]-tight bottom to ! filt]1 & its l[ position1 a c]ta9 am\nt ( wat] con/antly ent]$ ! filt] f ! gr\nd bel[4 ,?is wat] conta9$ iron 9 solution z f]r\s c>bonate4 ,:5 ?is wat] came 9 contact ) ! filt]$ wat] 9 ! gravel & und]dra9s1 ! iron 0 oxidiz$ by ! dissolv$ oxyg5 c>ri$ 9 ! filt]$ wat] & precipitat$4 ,?is 0 accompani$ by a gr[? ( cr5o?rix 9 ! gravel & und]dra9s1 :i* gradually r$uc$ _! c>ry+ capacity4 ,?is r$uction 9 c>ry+ capacity fir/ became app>5t 9 cold wea!r :5 ! yield f ! filt] 0 less free ?an =m]ly4 ,!re 0 difficulty 9 ma9ta9+ ! supply dur+ ! w9t] ( #ahif-g & m difficulty 9 ! foll[+ w9t]4 ,illu/ration3 ,,fig4 #af4--,,typhoid ,,fev] ,,9 ,,lawr5ce1 #ahhh ,,to #ahih4 ,! s& ( ! filt] 0 z capable ( filt]+ ! full supply ( wat] z x ev] _h be51 & ! effici5cy 0 z good2 b ! und]dra9s 7 no long] able to collect ! filt]$ wat] & deliv] x4 ,z ! filt]+ area 0 ample = ! supply1 x 0 desir$ to avoid con/ruction ( additional filt]+ area4 ,! und]dra9s 7 dug up & clean$ dur+ ! p]iods :5 ! filt] 0 dra9$4 ,z ! filt] is all 9 "o b$1 ! times :5 ! filt] c\ld be all[$ to rema9 dra9$1 & :5 ! "w c\ld proce$1 7 limit$4 ,great c>e 0 tak5 to leave ! "w 9 good condition1 & free f passages1 at ! end ( ea* day's "w1 b ! numb]s ( bact]ia 9 ! efflu5t nev]!less increas$ some:at4 ,"s weeks aft]w>d ! numb] ( cases ( typhoid fev] 9 ! city increas$4 ,! numb]s did n become z high z !y _h be5 prior to ! introduction ( filt]$ wat]1 b !y 7 mu* high] ?an !y _h be5 s9ce t "t1 & !y po9t$ /rongly to ! di/urbance ( ! und]dra9s z ! cause ( ! increase4 ,! numb]s ( bact]ia 9 ! appli$ wat] & 9 ! efflu5t f ! ,lawr5ce filt] by mon?s1 f ! "t ! filt] 0 put 9 op]ation1 compil$ f ! reports ( ! ,/ate ,bo>d ( ,heal?1 z f> z available1 are z foll[s3 ,,bact]ia ,,9 ,,wat] ,,appli$ ,,to ,,& ,,efflu5t ,,f ,,lawr5ce ,,filt]4 ,,raw ,,wat]4 ---------------------------------------- ------------------------ #ahic4 #ahid4 #ahie4 #ahif4 #ahig4 #ahih4 ---------------------------------------- ------------------------ ,janu>y #g1gjj #ah1gjj #g1ejj #ac1cad #f1eai ,febru>y #g1fjj #ae1jdj #ab1fjj #ac1aac #d1fec ,m>* #f1ejj #bj1ggj #e1ijj #ab1jee #c1gdh ,april #aa1bjj #h1dbj #c1hjj #f1ijd #b1cbj ,may #f1jjj #g1jjj #i1fjj #d1fbe #b1jej ,june #h1cjj #i1jjj #f1djj #d1fej #f1gge ,july #b1djj #aj1jjj #c1ijj #f1bdj #b1hdj ,augu/ #c1ajj #e1jjj #b1gjj #aj1gjj #h1ege ,septemb] #eg1ejj #f1ejj #e1jjj #ab1cjj #bg1cjj #f1ajj ,octob] #bb1bjj #be1cjj #ai1jjj #e1cjj #ac1bjj #e1abj ,novemb] #aj1hjj #af1fjj #h1gjj #e1fjj #f1fdd #d1caj ,decemb] #h1ajj #bc1hjj #f1gjj #i1fie #e1eha #e1bjj ---------------------------------------- -------- ,av]age #bd1fej #aj1dag #aa1aaa #g1ajh #aj1cfj #d1hej ,,efflu5t4 ,janu>y #abi #bjf #aff #ia #ci ,febru>y #bdd #bhc #cae #gi #de ,m>* #dee #dje #acc #fg #cd ,april #bha #hd #dj #dg #ba ,may #acd #fh #ef #ce #dh ,june #aaj #fh #bb #ef #ej ,july #be #ej #ci #ajf #bb ,augu/ #cf #ch #adf #gb #bh ,septemb] #f1hej #db #dj #cg #ih #fg ,octob] #a1baf #aaf #fj #cj #cc #bh ,novemb] #afa #age #fd #cg #bg #abb ,decemb] #aaa #cfd #hd #fg #bd ---------------------------------------- -------- ,av]age #b1jhd #agf #aba #ia #fa #df ,av]age effici5cy #ia4ee #ih4ca #ih4ia #ih4gb #ii4da #ih4ie ,,*emnitz ,,wat]-,,works4 ,! only o!r place :i* ,i h f\nd :]e any?+ approa*+ int]mitt5t filtration ( wat] is sy/ematically employ$ is ,*emnitz1 ,g]many4 ,! me?od !re us$ be>s ! same relation to int]mitt5t filtration z does broad irrigation ( sewage to ! correspond+ me?od ( sewage treatm5t2 t is1 ! pr9ciples involv$ are ma9ly ! same1 b a mu* l>g] filt]+ area is us$1 & ! processes take place at a l[] rate & "u less close control4 ,illu/ration3 ,,fig4 #ag4--,,plan ,,( ,,area ,,us$ ,,= ,,int]mitt5t ,,filtration ,,at ,,*emnitz4 ,! wat]-works 7 built ab\t tw5ty ye>s ago by plac+ ?irty-n9e wells along ! ,zwnitz ,riv]1 connect$ by siphon pipes1 ) a pump+-/ation :i* =c$ ! wat] to an elevat$ res]voir ne> ! city 7,fig4 #ag74 ,! wells are built ( masonry1 #e or #f feet 9 diamet] & #aj or #ab feet deep1 & are on ! r l[ bank ( ! riv]4 ,! mat]ial1 ) ! exception ( ! surface soil1 & loam ab\t #c feet deep1 is a some:at mix$ gravel ) an effective size ( probably f #j4be to #j4ej mm41 s t wat] is able to pass ?r\gh x freely4 ,! wells are1 on an av]age1 ab\t #abj feet ap>t1 & ! l9e is sev5 eigh?s ( a mile long4 ,x 0 f\nd t 9 dry times ! gr\nd-wat] level 9 ! entire neighborhood 0 l[]$ "s feet bel[ ! level ( ! riv] )\t ei!r furni%+ wat] en\gh or /opp+ ! fl[ ( ! riv] bel[4 ,! *annel ( ! riv] 0 s silt$ t1 not)/&+ ! por\s mat]ial1 ! wat] c\ld n p5etrate x to g t[>d ! wells4 ,a dam 0 n[ built across ! riv] ne> ! pump+-/ation1 & a canal 0 dug f above ! dam1 cross+ ! l9e ( wells & runn+ p>allel to x on ! back side = ab\t half a mile4 ,lat] a simil> canal 0 dug back ( ! rema9+ upp] wells4 ,ow+ to ! diff]5ce 9 level 9 ! riv] above & bel[1 ! canals c be empti$ & fill$ at pleasure4 ,!y are built ) c>efully prep>$ s& bottoms1 & ! s& sides are protect$ by an op5 pav+1 to all[ ! p]colation ( z mu* wat] z possible1 & ! s& is clean$ by scrap+1 z is usual ) ord9>y s& filt]s1 once a ye> or (t5]4 ,! yield f ! wells 0 mu* increas$ by ^! canals1 b ! wat] ( ! riv] is pollut$ to an ext5t :i* w\ld ord9>ily q prev5t ev5 ! ?\ght ( its be+ us$ = wat]-supply1 & x 0 f\nd t ! wat] go+ into ! gr\nd f ! canals1 & pass+ ?r\gh ! always saturat$ gravel to ! wells1 )\t com+ 9 contact ) air at any po9t1 aft] a "t conta9$ iron & _h an objectionable odor4 ,to avoid ?is disagreeable result ! mead[ bel[ ! pump+-/ation 0 laid out z an irrigation field 7,fig4 #af74 ,! wat] f above ! dam 0 tak5 by a canal on ! opposite side ( ! riv] ?r\gh a s$im5tation pond 7:i*1 h[ev]1 is n n[ believ$ to be necess>y & is n always us$71 & !n "u ! riv] by a siphon to a slightly elevat$ po9t on ! mead[1 f :i* x is di/ribut$ by a sy/em ( op5 dit*es1 exactly z 9 sewage irrigation4 ,! area irrigat$ is n exactly def9$ & v>ies some:at f "t to "t2 ! rate ( filtration may be r\ghly e/imat$ at f #ajj1jjj to #aej1jjj gallons p] acre daily1 al?\gh limit$ portions may occasionally get five times ^! quantities = a s+le day4 ,! wat] passes ?r\gh ! ?ree feet ( soil & loam1 & aft]w>d ?r\gh an av]age ( six feet ( dra9$ co>se s& or gravel 9 :i* x meets air1 & aft]w>d filt]s lat]ally ?r\gh ! saturat$ gravel to ! wells4 ,! wat] s obta9$ is inv>iably ( good quality 9 e way1 colorless1 free f odor & f bact]ia4 ,! surface ( ! irrigat$ l& is cov]$ ) grass & has fruit-trees 7mo/ly apple7 at int]vals ov] its entire area4 ,?is fir/ sy/em ( irrigation is entirely by gravity4 ,on acc\nt ( natural limits to ! l& x c\ld n be conv5i5tly ext5d$ at ?is po9t1 & to secure m area1 ! high] l& above ! pump+-/ation 0 be+ made into an irrigation field 9 #ahid4 ,?is is too high to be flood$ by gravity1 & w be us$ only = %ort p]iods 9 extremely dry wea!r4 ,! wat] is elevat$ ! few feet necess>y by a gas-eng9e on ! riv]-bank4 ,9 times ( wet wea!r en\gh wat] is obta9$ f ! wells )\t irrigation1 & ! l& is only irrigat$ :5 ! gr\nd-wat] level is too l[4 ,dur+ ,decemb]1 ,janu>y1 & ,febru>y irrigation is usually impossible on acc\nt ( temp]ature1 & ! canals are !n us$1 keep+ !m fill$ ) wat] s t freez+ to ! bottom is impossible2 b tr\ble ) bad odors 9 ! filt]$ wat] drawn f ! wells is exp]i5c$ at ^! times4 ,! dra9age area ( ! ,zwnitz ,riv] is only ab\t #dd squ>e miles1 & ^u x are a l>ge numb] ( villages & factories1 s t ! wat] is excessively pollut$4 ,! wat] 9 ! wells1 h[ev]1 :e!r com+ f natural s\rces1 or f irrigation1 or f ! canals1 has nev] _h z _m z #ajj bact]ia p] cubic c5timet]1 & is reg>d$ z entirely :olesome4 ,9 extremely dry wea!r ! riv]1 ev5 :5 x is all us$ = irrigation s t h>dly any fl[s away bel[1 _c be made to supply ! necess>y daily quantity ( #b1fej1jjj gallons1 & to supply ! defici5cy at su* times1 z well z to avoid ! use ( ! canals 9 w9t]1 a /orage res]voir hold+ #ie1jjj1jjj gallons has rec5tly be5 built on a fe$] ( ! riv]4 ,?is wat]1 :i* is f an un9habit$ dra9age area1 is filt]$ ?r\gh ord9>y cont9u\s filt]s & fl[s to ! city by gravity4 ,ow+ to ! small area ( ! wat]%$ x is incapable ( supply+ m ?an a fraction ( ! wat] = ! city1 & w be us$ to supplem5t ! old] works4 ,?is ,*emnitz plant is ( especial int]e/ z %[+ ! successful utilization ( a riv]-wat] s grossly pollut$ z to be incapable ( treatm5t by ! ord9>y me?ods4 ,results obta9$ at ! ,lawr5ce ,exp]im5t ,/ation h %[n t sewage is incapable ( be+ purifi$ by cont9u\s filtration1 ! action ( air be+ ess5tial = a satisfactory result4 ,) ord9>y wat]s only mod]ately pollut$ ?is is n s2 = !y c>ry en\gh dissolv$ air to effect _! own purification4 ,9 ,*emnitz1 h[ev]1 z %[n by ! results ) ! canals1 ! pollution is s great t cont9u\s filtration is inadequate to purify ! wat]1 & ! int]mitt5t filtration adopt$ is ! only me?od likely to yield satisfactory results 9 su* cases4 ,int]mitt5t filtration is n[ be+ adopt$ = purify+ brooks dra9+ c]ta9 villages & dis*>g+ into ! ponds or res]voirs f :i* ,bo/on draws its wat]-supply4 ,! wat] ( ,pegan ,brook bel[ ,natick has be5 s filt]$ s9ce #ahic ) mo/ satisfactory results1 & af=ds almo/ absolute protection to ,bo/on f any infection :i* might o!rwise ent] ! wat] f t t[n4 ,a simil> treatm5t is soon to be giv5 to a brook dra9+ ! city ( ,m>lbor\gh4 ,! sewage f ^! places is n dis*>g$ into ! brooks1 b is o!rwise provid$ =1 b nev]!less !y receive _m pollut+ matt]s f ! h\ses & /reets ^u _! banks4 ,! filtration us$ resembles 9 a measure t at ,*emnitz1 & ,i am in=m$ by ! eng9e]1 ,mr4 ,desmond ,fitz,gerald1 t x 0 adopt$ on acc\nt ( its conv5i5ce = ?is p>ticul> problem1 & n because he atta*es any special virtue to ! int]mitt5t feature4 ,,application ,,( ,,int]mitt5t ,,filtration4 ,9 reg>d to ! use ( wat]s z grossly pollut$ z ! ,zwnitz1 ! t5d5cy is /rongly to avoid _! use1 no matt] h[ complete ! process ( purification may be2 b 9 case x %\ld be deem$ necess>y to use s impure a wat] = a public supply1 int]mitt5t filtration is ! only process kn[n :i* w\ld adequately purify x4 ,& x %\ld be us$ at comp>atively l[ rates ( filtration4 ,i believe t an attempt to filt] ! ,zwnitz at ! rate us$ = ! ,m]rimac wat] at ,lawr5ce1 :i* is by comp>ison b slightly pollut$1 w\ld result disa/r\sly4 ,! op]ation 9 w9t] mu/ also be consid]$4 ,int]mitt5t filtration ( sewage on op5 fields 9 ,massa*usetts w9t]s is only possible because ( ! comp>atively high temp]ature ( ! sewage 7usually #dj to #ej71 & w\ld be a dismal failure ) sewage at ! freez+-po9t1 ! temp]ature to be expect$ 9 riv]-wat]s 9 w9t]4 ,x is impossible to draw a %>p l9e betwe5 ^? wat]s :i* are s badly pollut$ z to require int]mitt5t filtration = _! treatm5t & ^? :i* are susceptible to ! ord9>y cont9u\s filtration4 ,examples ( riv]-wat]s pollut$ probably beyond ! limits rea*$ 9 any ,am]ican wat]s us$ = dr9k+ purposes & successfully filt]$ ) cont9u\s filt]s are furni%$ by ,altona1 ,breslau1 & ,london4 ,int]mitt5t filtration may be consid]$ 9 ^? cases :]e x is propos$ to use a wat] pollut$ entirely beyond ! ord9>y limits1 & = wat]s conta9+ l>ge quantities ( decomposable organic matt]s & microscopical organisms2 b 9 ^? cases :]e a c]ta9 & exp$iti\s removal ( mud is desir$1 & :]e wat]s are only mod]ately pollut$ by sewage1 b /ill 9 _! raw /ate are unheal?y1 x is n app>5t t int]mitt5t filtration has any advantages comm5surate ) ! disadvantages ( increas$ rate to produce ! same total yield & ( ! increas$ difficulty ( op]ation1 p>ticul>ly 9 w9t]2 & 9 su* cases cont9u\s filtration is to be pref]r$4 ,9 ! removal ( ta/es & odors f pond or res]voir wat]s :i* are n muddy1 b :i* are subject to ! gr[?s ( l[ =ms ( plants1 :i* ei!r by _! gr[? or decomposition imp>t to ! wat] disagreeable ta/es & odors1 int]mitt5t filtration may h a di/9ct advantage4 ,9 su* cases !re is (t5 an excess ( organic matt] to be dispos$ ( by oxidation1 & ! additional a]ation secur$ by int]mitt5t filtration is ( sub/antial assi/ance 9 dispos+ ( ^! matt]s4 ,,*apt] ,,viii4 ,,turbidity ,,& ,,color1 ,,& ,,! ,,effect ,,( ,,mud ,,^u ,,s&-,,filt]s4 ,! ideal wat] 9 appe>ance is di/ill$ wat]1 :i* is p]fectly cle> & limpid1 & has a slight blue color4 ,:5 o!r wat]s are comp>$ ) x1 ! div]g5ces 9 color f ! color ( di/ill$ wat] are measur$1 & n ! absolute colors ( ! wat]s4 ,_m spr+ wat]s & filt]$ wat]s are indi/+ui%able 9 appe>ance f di/ill$ wat]4 ,public wat]-supplies f surface s\rces conta9 two sub/ances or classes ( sub/ances :i* injure _! appe>ance1 namely1 peaty color+ matt]s1 & mud4 ,wat]s discolor$ by peaty matt]s are mo/ common 9 ,new ,engl& & 9 c]ta9 p>ts ( ! ,nor?we/1 :ile muddy wat]s are f\nd almo/ ev]y:]e1 b ( diff]5t degrees ( mudd9ess1 accord+ to ! physical conditions ( ! wat]-%$s f :i* !y are obta9$4 ,muddy wat]s are (t5 spok5 ( z color$ wat]s1 & 9 a s5se ?is is correct :]e ! mud consi/s ( clays or o!r mat]ials hav+ di/9ct colors2 b x is m conv5i5t to classify impurities ( ?is k9d z turbidities only1 & to limit ! t]m color$ wat]s to ^? wat]s conta9+ 9 solution vegetable matt]s :i* color !m4 ,! removal ( ei!r color or turbidity may be call$ cl>ification4 ,color$ wat]s are usually drawn f wat]-%$s :]e ! und]ly+ rock is h>d & does n rapidly dis9tegrate1 & :]e ! soils are firm & s&y1 & especially f swamps4 ,! wat] "h comes 9 contact ) peat or muck1 :i* colors x1 b is s firm z n to be wa%$ by flood fl[s1 & s does n cause turbidity4 ,l>ge p>ts ( ! ,unit$ ,/ates h = rock f\ndations %ales or o!r s(t mat]ials :i* readily dis9tegrate :5 expos$1 & :i* =m clayey soils readily wa%$ by h>d ra9s4 ,wat]s f su* wat]%$s are g5]ally turbid & v r>ely color$4 ,9 fact a wat] c>ry+ mu* clay 9 susp5sion is usually f\nd colorless :5 ! clay is remov$1 ev5 if x 7 orig9ally color$4 ,x ?us happ5s t wat]s :i* are color$ & turbid at ! same "t h>dly exi/ 9 nature4 ,color-produc+ matt]s & turbidity-produc+ matt]s are diff]5t 9 _! natures1 & ! me?ods :i* mu/ be us$ to remove !m are diff]5t4 ,,! ,,measurem5t ,,( ,,color4 ,! colors ( wat]s are measur$ & record$ by comp>+ !m ) colors ( solutions or sub/ances :i* are p]man5t1 or :i* c be reproduc$ at w4 ,"o ( ! e>lie/ me?ods ( measur+ colors ( wat]s 0 to comp>e !m ) ! colors ( ! ,nessl] /&>ds us$ = ! e/imation ( ammonia 9 wat] analysis4 ,! ,nessl] /&>ds 7 simil> 9 appe>ance to yell[ wat]s1 & _! colors dep5d$ ^u ! am\nts ( ammonia :i* _h be5 us$ 9 prep>+ !m1 & a record 0 made ( ! /&>d :i* mo/ closely resembl$ ! wat] "u exam9ation4 ,! me?od 0 op5 to ! s]i\s objections t ! hues ( ! /&>ds did n mat* closely ! hues ( ! wat]s2 t ! colors produc$ ) diff]5t lots ( ,nessl] reag5t diff]$ consid]ably1 & !re=e ! exact values ( results 7 m or less unc]ta92 & fur!r1 t ! numb]s obta9$ = color 7 n ev5 approximately proportional to ! am\nts ( color+ matt] pres5t4 ,because ( ?is peculi>ity1 9 filtration ! p]c5tage ( color removal1 z det]m9$ by ! use ( ^! /&>ds1 is n ev5 approximately correct1 b is mu* above ! tru?4 ,9 ! ,lovibond t9tomet]1 :i* has be5 ext5sively us$ 9 ,engl&1 ! /&>ds ( color are bas$ ^u ! colors ( c]ta9 glass slips1 :i* are 9 turn comp>$ ) /&>d orig9als kept = t purpose4 ,?is process answ]s q well1 b is op5 to "s objections because ( possible unc]ta9ties 9 ! /&>dization ( ! units4 ,ano!r me?od ( measur+ colors is to comp>e !m ) dilute solutions ( plat9um & cobalt4 ,! ratio ( cobalt to plat9um c be v>i$ to make ! hue correspond v closely ) ! hues ( natural wat]s1 & ! am\nt ( plat9um requir$ to mat* a wat] af=ds a measure ( its color1 "o "p ( metallic plat9um 9 #aj1jjj p>ts ( wat] =m+ ! unit ( color4 ,?is /&>d has ! advantages t x c be readily prep>$ ) absolute accuracy 9 any laboratory1 & t by v>y+ ! ratio ( plat9um to cobalt ! hues ( v>i\s wat]s c be mo/ p]fectly mat*$4 ,x is important t ! obs]vations %\ld n be made 9 too great a dep?1 z ! discrepancy 9 hues increases mu* m rapidly ?an ! dep? ( color4 ,= fur!r in=mation reg>d+ colors ! read] is ref]r$ to articles 9 ! ,am]ican ,*emical ,j\rnal1 #ahib1 vol4 xiv1 page #cjj2 ,j\rnal ( ! ,am]ican ,*emical ,society1 vol4 ii1 page #h2 vol4 xviii1 #ahif1 pp4 #fh1 #bfd1 & #dhd2 ,j\rnal ( ! ,frankl9 ,in/itute1 ,dec4 #ahid1 p4 #djb2 ,j\rnal ( ! ,new ,engl& ,wat] ,works ,association1 vol4 xiii1 #ahih1 p4 #id4 ,,am\nt ,,( ,,color ,,9 ,,am]ican ,,wat]s4 ,new ,engl& surface-wat]s h colors rang+ f almo/ no?+ up to #b4jj4 ,! colors ( ! public wat]-supplies ( ,massa*usetts cities h be5 record$ 9 ! reports ( ! ,/ate ,bo>d ( ,heal? = "s t5 ye>s4 ,! figures giv5 7 record$ fir/ ^u ! ,nessl] /&>d1 & aft]w>ds ^u a modification ( ! same1 kn[n z ! natural wat] /&>d4 ,! figures giv5 are approximately equal to ^? = ! plat9um color /&>d1 ! relations betwe5 ! two hav+ be5 frequ5tly det]m9$ by v>i\s obs]v]s & publi%$ 9 ! above-m5tion$ pap]s4 ,! accompany+ diagram %[s ! colors 9 sev]al ,massa*usetts supplies1 z plott$ f ! figures giv5 9 ! publi%$ reports4 ,illu/ration3 ,,fig4 #ah4--;,,colors ,,( ,,wat]s4 7,analyses ( ! ,mass4 ,/ate ,bo>d ( ,heal?47 ,9 ,connecticut also ! colors ( _m public wat]-supplies h be5 record$ 9 ! reports ( ! ,/ate ,bo>d ( ,heal? on ! plat9um color-/&>d4 ,! wat]s ( ! ,middle ,/ates1 ) r>e exceptions1 are almo/ free f color4 ,9 ! ,nor?we/ wat]s are obta9$ (t5 ) v high colors1 ev5 consid]ably high] ?an ! ,new ,engl& wat]s1 & "s ( ! ,s\!rn swamps also yield highly color$ wat]s4 ,,removal ,,( ,,color4 ,peaty color+-matt] is almo/ p]fectly 9 solution1 & only a portion ( x is capable ( be+ remov$ by any =m ( simple filtration4 ,9 ord] to remove ! color+-matt] x is necess>y to *ange x *emically1 or to br+ x into contact ) "s sub/ance capable ( absorb+ x4 ,= ?is reason s& filtration ) ord9>y s&s1 hav+ no absorptive p[] = color1 commonly removes only f "o f\r? to "o ?ird ( ! color ( ! raw wat]4 ,,measurem5t ,,( ,,turbidity4 ,! am\nt ( mud or turbidity 9 a wat] is (t5 express$ z ! weight ( ! susp5d$ matt]s 9 a giv5 weight ( ! wat]4 ,mo/ ( ! data relat+ to turbidities ( wat]s are /at$ 9 ?is way1 because ?is 0 ! only me?od recogniz$ by ! e>li] inve/igators4 ,?is me?od ( /atem5t has "s disadvantages3 x fails to take into acc\nt ! diff]5t sizes ( p>ticles :i* are c>ri$ 9 susp5sion by diff]5t wat]s1 & at diff]5t times4 ,?us ! ,m]rimac ,riv] 9 a great flood may c>ry #ajj p>ts 9 #ajj1jjj ( f9e s& 9 susp5sion1 & /ill x c\ld h>dly be call$ muddy2 :ile ano!r /ream c>ry+ only a fraction ( ?is am\nt ( f9e clay w\ld be extremely muddy4 ,fur!r1 an accurate det]m9ation ( susp5d$ matt]s is a v tr\blesome & t$i\s op]ation1 & _c be und]tak5 z frequ5tly z is necess>y = an adequate /udy ( ! mud "q4 ,turbidity is pr9cipally important z x affects ! appe>ance ( wat]1 & x w\ld seem t optical r ?an gravimetric me?ods %\ld be us$ = its det]m9ation4 ,v>i\s optical me?ods ( measur+ turbidity h be5 propos$4 ,! g5]al me?od employ$ is to measure ! ?ickness ( ! lay] ( wat] ?r\gh :i* "s object c be se5 "u def9ite conditions ( light+4 ,! mo/ accurate results c probably be obta9$ 9 clos$ receptacles & ) artificial light4 ,su* a me?od has be5 us$ by ,mr4 ,g4 ,w4 ,full] at ,l\isville & ,c9c9nati 9 connection ) 8 exp]im5ts1 & is describ$ by ,p>melee & ,ellms 9 ! ,te*nology ,qu>t]ly = ,june1 #ahii4 ,?is app>atus is call$ by ,mr4 ,full] a diaphanomet]4 ,at ! ,lawr5ce ,exp]im5t ,/ation ( ! ,massa*usetts ,/ate ,bo>d ( ,heal? z e>ly z #ahhi x became necess>y to express ! turbidities ( v>i\s wat]s approximately1 & ! v simple device ( /ick+ a p9 into a /ick1 & pu%+ x d[n into ! wat] "u exam9ation z f> z x c\ld be se51 0 adopt$4 ,aft]w>ds a plat9um wire #j4jd ( an in* 9 diamet] 0 sub/itut$ = ! p91 & ! /ick 0 graduat$ s t ! turbidities c\ld be read f x directly4 ,! figures on ! /ick 7 inv]sely proportional to _! di/ances f ! wire4 ,:5 ! wire c\ld be se5 "o in* bel[ ! surface1 ! turbidity 0 report$ z #a4jj2 :5 ! wire c\ld be se5 two in*es1 ! turbidity 0 #j4ej1 & :5 x c\ld be se5 t5 in*es ! turbidity 0 #j4aj1 etc4 ,?is scale is mu* m conv5i5t ?an a scale %[+ ! dep? at :i* ! wire c be se52 & )9 c]ta9 limits ! figures obta9$ ) x are directly proportional to ! am\nt ( ! elem5ts :i* ob/ruct light 9 ! wat]4 ,?us1 if a wat] hav+ a turbidity ( #a4jj is mix$ ) an equal volume ( cle> wat]1 ! mixture w h a turbidity ( #j4ej4 ,advantage is tak5 ( ?is fact = ! measurem5t ( turbidities s great t !y _c be accurately det]m9$ by direct obs]vation4 ,= turbidities mu* above #a4jj x is v difficult to read ! dep? ( wire ) suffici5t accuracy1 & su* wat]s are dilut$ ) "o1 two1 or m times _! volume ( cle> wat] 9 a pail or o!r receptacle1 ! turbidity ( ! dilut$ wat] is tak51 & multipli$ by ! appropriate factor4 ,= ! greate/ accuracy x is necess>y t ! obs]vations %\ld be tak5 9 ! op5 air & n "u a ro(4 ,!y %\ld pref]ably be made 9 ! middle ( ! day :5 ! light is /ronge/1 & 9 case ! sun is %9+1 ! wire mu/ be kept 9 %ad[ & n 9 direct sunlight4 ,! turbidities ( efflu5ts are usually s slight t !y _c be tak5 9 ?is mann]2 9 fact1 turbidities ( less ?an #j4jb1 ) ! wire visible #ej in*es bel[ ! surface1 _c be conv5i5tly read 9 ?is way4 ,= ! e/imation ( l[] turbidities a wat] is tak5 hav+ a turbidity ( #j4jc or #j4jd & z free z possible f l>ge susp5d$ p>ticles4 ,! turbidity ( ?is wat] is measur$ by a plat9um wire 9 ! usual way1 & ! wat] is !n dilut$ ) cle> wat] to make /&>ds = ! l[] turbidities4 ,! comp>isons betwe5 /&>ds & wat]s are be/ made 9 bottles ( p]fectly cle> glass1 hold+ at lea/ a gallon1 & ! comp>ison is facilitat$ by surr\nd+ ! bottles ) black clo? except at ! po9t ( obs]vation1 & light+ ! wat] by electric lights s arrang$ t ! light passes ?r\gh ! wat] b is hidd5 f ! obs]v]4 ,9 case ! wat] "u exam9ation is color$1 ! comp>ison is r5d]$ difficult1 & x is (t5 advisable to add a small am\nt ( me?yl orange to ! /&>ds to make ! colors equal4 ,in/ead ( dilut+ a wat] ( kn[n turbidity = ! /&>ds1 a /&>d c be made by precipitat+ a kn[n am\nt ( silv] *loride 9 ! wat]4 ,= ?is purpose ab\t "o p] c5t ( common salt is dissolv$ 9 cle> wat] & small measur$ am\nts ( silv] nitrate add$1 until ! turbidity produc$ is equal to t ( ! wat] "u exam9ation4 ,! relation ( ! am\nt ( silv] nitrate us$ to ! turbidity is entirely arbitr>y1 & is e/abli%$ by comp>isons ( /&>ds made 9 ?is way ) wat]s hav+ turbidities f #j4jb to #j4jd1 ! turbidities ( :i* are measur$ ) ! plat9um wire1 & :i* aft]w>ds s]ve to rate ! /&>ds4 ,! silv] *loride has a slight color1 :i* is an objection to its use1 & p]haps "s o!r sub/ance c\ld be sub/itut$ = x ) advantage4 ,! /&>ds h to be made fre%ly ea* day4 ,"o disadvantage ( ! plat9um-wire me?od ( obs]v+ turbidities 9 ! op5 air1 z comp>$ ) ! diaphanometric me?od us+ artificial light1 is t obs]vations _c be made 9 ! night4 ,to get ! g5]al "* ( ! wat] 9 a /ream1 daily obs]vations tak5 ab\t noon w g5]ally be suffici5t2 b = "s purposes x is important to "k ! turbidity at diff]5t h\rs ( ! day1 & 9 su* cases ! plat9um-wire me?od is at a di/9ct disadvantage4 ,v>iations 9 ! am\nt ( light1 )9 reasonable limits1 d n affect ! results mat]ially1 al?\gh extreme v>iations are to be avoid$4 ,! size ( ! wire also influ5ces ! results some:at4 ,! wire commonly us$ is #j4jd ( an in* or "o millimet] 9 diamet]4 ,a wire only f\r t5?s ( ?is size 9 "s exp]im5ts at ,pittsburg gave results #be p] c5t high]2 ) a wire twice z l>ge ! results 7 l[]1 b ! diff]5ces 7 mu* less4 ,wire #j4jd ( an in* 9 diamet] 0 adopt$ z be+ v well adapt$ to r turbid riv]-wat]s4 ,= v cle> lake or res]voir wat]s1 usually transp>5t to a great dep?1 a mu* l>g] object is pref]able4 ,)9 c]ta9 limits ! results obta9$ ) an object ( any size c be conv]t$ into correspond+ figures = ano!r object1 or ano!r light1 by ! use ( a con/ant factor4 ,?us ! turbidities obta9$ ) a plat9um wire always h approximately ! same ratio to ! turbidities ( ! same wat]s det]m9$ by ! diaphanomet]4 ,! plat9um-wire me?od has be5 us$ 9 _m cases ) mo/ satisfactory results4 ,if x lacks some?+ 9 !oretical accuracy z comp>$ ) m elaborate me?ods1 x m ?an makes up = x by its simplicity2 & reliable obs]vations c be tak5 ) x by p :o w\ld be entirely incompet5t to op]ate m elaborate app>atus2 & x c ?us be us$ 9 _m cases :]e o!r me?ods w\ld be impossible4 ,^u ?is scale ! mo/ turbid wat]s :i* h come "u ! obs]vation ( ! au?or h turbidities ( ab\t #b4ej1 al?\gh wat]s mu* m turbid ?an ?is und\bt$ly exi/4 ,a wat] ) a turbidity ( #a4jj is extremely muddy1 & only "o t5? ( ?is turbidity w\ld cause rem>k & compla9t among ^? :o use x = dome/ic purposes4 ,9 an ord9>y press$-glass tumbl] a turbidity ( #j4jb is j visible to an ord9>y obs]v] :o looks at ! wat] closely1 b x is n conspicu\s1 nor w\ld x be likely to cause g5]al compla9t2 & ?is am\nt may be tak5 z approximately ! all[able limit ( turbidity 9 a good public wat]-supply4 ,9 a c>efully poli%$1 & p]fectly transp>5t glass a turbidity ( #j4ja w be visible1 & 9 l>g] receptacles /ill l[] turbidities may be se5 if ! wat] is exam9$ c>efully4 ,9 gallon bottles ( v cle> glass1 "u electric light & surr\nd$ by black clo?1 a turbidity ( #j4jja c be di/+ui%$1 b a turbidity ev5 sev]al times z l>ge z ?is c\ld h>dly be detect$ except by ! use ( special appliances1 or :]e wat] is se5 9 a dep? ( sev]al feet4 ,,relation ,,( ,,plat9um-,,wire ,,turbidities ,,to ,,susp5d$ ,,matt]s4 ,! relation ( turbidity to ! weight ( susp5d$ matt]s is approximately con/ant = wat]s f :i* ! co>s] matt]s h be5 entirely remov$ by s$im5tation4 ,= ^! wat]s ! susp5d$ matt]s 9 p>ts p] #ajj1jjj are ab\t #af times ! turbidity4 ,= riv]-wat]s ! ratios are always l>g]4 ,) v sluggi% riv]s ! ratio is only a little l>g] ?an = settl$ wat]s4 ,= av]age riv]-wat]s ! ratio is consid]ably high]1 & increases ) ! turbidity1 & = v rapid riv]s & torr5ts ! ratio is mu* wid]1 z ! susp5d$ matt]s consi/ l>gely ( p>ticles :i* are heavy b d n increase v mu* ! turbidity4 ,! foll[+ table gives ! am\nts ( susp5d$ matt]s = v>i\s classes ( wat]s correspond+ to ! turbidities /at$1 :i* h be5 d$uc$ f ! exp]i5ce ( ! au?or4 ,x is v likely t ratios diff]5t f ! above w\ld be obta9$ ) wat]s 9 :i* ! s$im5t 0 ( diff]5t "*4 ---------------------------------------- --------------------- ,susp5d$ ,matt]s3 ,p>ts 9 #ajj1jjj4 ,turbidity1 ---------------------------------------- ------- ,plat9um-wire ,riv] ,riv] ,riv] ,/&>d4 ,settl$ ,wat]s1 ,wat]s1 ,wat]s1 ,wat]s4 ,f9e/ ,av]age ,co>se/ ,s$im5t4 ,s$im5t4 ,s$im5t4 ---------------------------------------- ------------------ #j4ja #j4af #j4je #j4hj #j4he #a4cj #b4dj #j4aj #a4fj #a4ge #b4fj #d4ij #j4bj #c4bj #c4fj #e4ej #aj4jj #j4cj #d4hj #e4gj #h4ej #ae4jj #j4dj #f4dj #g4hj #aa4fj #ba4jj #j4ej #h4jj #aj4jj #ae4jj #bf4jj #a4jj #af4jj #bc4jj #cf4jj #ei4jj #a4ej #bd4jj #dj4jj #fb4jj #ig4jj #b4jj #cb4jj #fa4jj #id4jj #adj4jj #c4jj #dh4jj #aaj4jj #age4jj #bej4jj ---------------------------------------- ------------------ ,,s\rce ,,( ,,turbidity4 ,mu* turbidity orig9ates 9 pl[$ fields ( clayey soil1 or 9 fields ^u :i* crops are gr[+4 ,if x has n ra9$ = "s days1 & ! surface-soil is comp>atively dry1 ! fir/ ra9 t falls ^u su* l& is absorb$ by ! pores ( ! soil until !y are fill$4 ,if ! ra9 is n heavy1 b little runs (f ov] ! surface4 ,if1 h[ev]1 ! ra9 cont9ues rapidly aft] ! surface-soil is saturat$1 ! excess runs (f ov] ! surface to ! ne>e/ wat]c\rse4 ,! impact ( ! ra9-drops ^u ! soil loos5s ! p>ticles1 & ! wat] fl[+ (f c>ries "s ( !m 9 susp5sion1 & ! wat] is said to be muddy4 ,! p>ticles c>ri$ (f 9 ?is way are extremely small4 ,mr4 ,george ,w4 ,full]1 9 8 report ^u wat] purification at ,l\isville1 e/imates t _m ( !m are n m ?an a hundr$ ?\s&? ( an in* 9 diamet]1 & n m ?an a t5? z l>ge z common wat] bact]ia4 ,! turbidity ( ! wat] fl[+ f a field ( loose soil may be #b4jj or m2 t is to say1 ! wire is hidd5 by a dep? ( half an in* ( wat] or less4 ,:5 ! wat] rea*es ! ne>e/ wat]c\rse x meets ) wat] f o!r k9ds ( l&1 su* z woodl&s & grass$ fields1 & ^! wat]s are less turbid4 ,! wat] 9 ! fir/ little wat]c\rse is ?us a mixture & has a turbidity ( p]haps #a4jj4 ,! conditions :i* control ! turbidity ( any brook are num]\s & complicat$4 ,! turbidity ( a /ream receiv+ v>i\s brooks dep5ds ^u ! turbidities ( all ! wat]s com+ into x4 ,g5]ally speak+1 ! turbidity ( a riv] dep5ds directly ^u ! turbidities ( its fe$]s1 & is n affect$ mat]ially by erosion ( its b$ or by s$im5tation 9 x4 ,!re are1 ( c\rse1 "s /reams :i* 9 times ( great floods cut _! banks1 & all /reams pick up & move ab\t f place to place m or less ( ! s& & o!r co>se mat]ials ^u _! bottoms4 ,! mat]ials ?us mov$1 h[ev]1 h b little influ5ce ^u ! turbidity4 ,aft] ! ra9 is ov] "s ( ! wat] held by ! soil w f9d its way to ! wat]c\rses by und]gr\nd *annels1 & w prev5t ! /ream f dry+ up betwe5 ra9s1 b ! av]age volume ( ! /ream-fl[s betwe5 ra9s w be mu* less ?an ! volumes dur+ ! ra9s :5 ! wat] is mo/ turbid4 ,illu/ration3 ,,fig4 #ai4--;,,fluctuations ,,9 ,,turbidity ,,( ,,! ,,wat] ,,( ,,! ,,allegh5y ,,riv] ,,at ,,pittsburg ,,dur+ #ahih4 ,^! conditions are well illu/rat$ by a few data ^u ! turbidity ( ?ree ,p5nsylvania /reams1 rec5tly collect$ by ! au?or4 ,"o ( ^! /reams is a small brook hav+ a dra9age area ( less ?an ?ree squ>e miles4 ,! obs]vations ext5d$ ov] a p]iod ( #dg days4 ,dur+ ?is "t !re 7 five floods1 or an av]age ( "o flood 9 t5 days4 ,! duration ( floods 0 less ?an tw5ty-f\r h\rs 9 ea* case4 ,select+ ! days :5 ! turbidity 0 ! highe/1 to ! numb] ( "o t5? ( ! :ole numb] ( days1 ! sum ( ! turbidities = ^! days 0 #fg p] c5t ( ! aggregate turbidities = ! :ole p]iod4 ,t is to say1 #fg p] c5t ( ! :ole am\nt ( mud 0 9 ! wat] ( only a t5? ( ! days2 ! wat] ( ! o!r n9e t5?s ( ! days conta9$ only #cc p] c5t ( ! :ole am\nt ( turbidity4 ,! av]age turbidity ( ! wat] = ! flood days 0 eighte5 times z great z ! av]age turbidity = ! rema9+ days4 ,! next /ream is a consid]able creek hav+ a dra9age area ( #cej squ>e miles4 ,! obs]vations ext5d$ ov] #aag days1 dur+ :i* "t !re 7 sev5 floods1 or an av]age ( "o flood 9 #ai days4 ,! floods la/$ 9 ea* case "o or two days1 & ! sum ( ! turbidities = ! "o t5? ( ! :ole numb] ( days :5 ! wat] 0 muddie/ 0 #ee p] c5t ( ! aggregate ( all ! turbidities = ! p]iod4 ,! la/ case is t ( a l>ge riv]1 ) a dra9age area ( ov] #aa1jjj squ>e miles4 ,! obs]vations ext5d$ ov] a full ye>4 ,9 ?is p]iod !re 7 sixte5 floods1 ea* la/+ f "o to six days1 & ! sum ( ! turbidities = ! "o t5? ( ! :ole numb] ( days :5 ! wat] 0 muddie/ is #de p] c5t ( ! aggregate turbidities = ! ye>4 ,! floods occurr$ on an av]age ( once 9 #bb days1 & ! av]age duration 0 two & "o half days4 ,! results are v /rik+ z %[+ t a v l>ge proportion ( ! mud is c>ri$ by ! wat] 9 flood fl[s ( comp>atively %ort duration4 ,!y also %[ t 9 small /reams ! proportion ( mud 9 ! flood-fl[s is great]1 & ! av]age duration ( floods is %ort]1 ?an 9 l>g] /reams4 ,9 o!r words1 ! diff]5ces betwe5 flood- & l[-wat] fl[s are greate/ 9 small /reams1 & gradually become less z ! size ( ! /ream increases4 ,:5 a /ream is us$ = wat]-works purposes 9 ! usual way1 a c]ta9 quantity ( wat] is tak5 f ! /ream ea* day1 :i* quantity is ne>ly con/ant1 & is n dep5d5t ^u ! condition ( ! /ream1 or ! volume ( its fl[4 ,! proportions ( ! total fl[s tak5 at high- & l[-wat] /ages are v diff]5t1 & x ?us happ5s t ! av]age quality ( ! wat] tak5 = wat]-works purposes is diff]5t f ! av]age quality ( all ! wat] fl[+ 9 ! /ream4 ,let u assume1 = example1 a /ream hav+ a wat]%$ ( su* a size t 9 times ( mod]ate floods wat] f ! mo/ di/ant po9ts rea*es ! wat]-works intake 9 tw5ty-f\r h\rs4 ,let u assume fur!r t ra9falls ( suffici5t int5sity to cause floods & muddy wat] occur1 on an av]age1 once 9 t5 days1 & t ! turbidity ( ! wat] at ^! times rea*es #a4jj1 & t = ! re/ ( ! "t ! turbidity av]ages #j4aj4 ,let u assume fur!r t at times ( /orms ! av]age fl[ ( ! /ream is #ajj units ( volume1 & = ! n9e days betwe5 /orms ! av]age fl[ is #aj units ( volume4 ,we %all !n h 9 a t5 days' p]iod1 = "o day1 #ajj volumes ( wat] ) a turbidity ( #a4jj1 & n9e days ) #aj volumes ea*1 or a total ( #ij volumes ( wat] ) a turbidity ( #j4aj4 ,! total dis*>ge ( ! /ream w !n be #aij volumes1 & ! av]age turbidity #j4eg4 ,! turbidity ( #j4eg repres5ts ! av]age turbidity all ! wat] fl[+ 9 ! /ream1 or1 9 o!r words1 ! turbidity :i* w\ld be f\nd 9 a lake if all ! wat] = t5 days %\ld fl[ into x & become ?or\ghly mix$ )\t o!r *ange4 ,n[ let u compute ! av]age turbidity ( ! wat] tak5 f ! /ream = wat]-works purposes4 ,! wat]-works require1 let u say1 "o volume ea* day1 & we h = ! fir/ day wat] ) a turbidity ( #a4jj1 & !n = n9e days wat] ) a turbidity ( #j4aj4 ,! av]age turbidity ( ! wat] tak5 by ! wat]-works = ! p]iod is ?us only #j4ai 9 place ( #j4eg1 ! av]age turbidity ( ! :ole run-(f4 ,! av]age turbidity ( all ! wat] fl[+ 9 ! /ream is ?us ?ree times z great z t ( ! wat] tak5 f ! /ream = wat]-works purposes4 ,x is (t5 not$ t ) long /reams ! wat] becomes muddi] f>!r d[n1 & x may naturally be ?\ght t x is because ( ! add$ erosion ( ! /ream ^u its b$ 9 its long] c\rse4 ,?is1 ( c\rse1 may be a cause1 or ! l[] tribut>ies may be muddi] ?an ! upp] ones1 b ! fact t ! wat] tak5 at ! l[] po9t is m muddy ?an f>!r up is n an indication ( ?is4 ,let u take1 = example1 a wat]%$ ( twice ! size ( t assum$ above1 t is1 s long t #dh h\rs w be requir$ = ! wat] f ! mo/ remote fe$]s to rea* ! wat]-works intake4 ,let u divide ?is %$ into two p>ts1 :i* we w assume to be equal1 "o ( :i* furni%es wat] rea*+ ! intake )9 #bd h\rs1 & ! o!r wat] rea*+ ! intake betwe5 #bd & #dh h\rs4 ,n[ suppose a /orm ^u ! wat]%$ produc+ turbidities equal to ^? j assum$ = ! small] /ream4 ,on ! fir/ day ! wat] f ! l[] half ( ! %$1 namely1 #ajj volumes hav+ a turbidity ( #a4jj1 passes ! intake1 b ?is is mix$ ) #aj volumes ( wat] f ! upp] half ( ! wat]%$1 hav+ a turbidity ( #j4aj1 & ! total fl[ is ?us #aaj volumes ( wat] hav+ a turbidity ( #j4ib4 ,on ! second day ! wat] f ! l[] half ( ! wat]%$ has return$ to its normal condition1 & ! flood-fl[ ( ! upp] half ( ! wat]%$1 #ajj volumes ) a turbidity ( #a4jj1 is pass+1 & m+les ) ! #aj volumes f ! l[] half ) a turbidity ( #j4aj1 & ! total fl[ is aga9 #aaj volumes hav+ a turbidity ( #j4ib4 ,! foll[+ eight days1 until ! next ra91 w h fl[s ( #bj volumes ea*1 ) turbidities ( #j4aj4 ,! av]age turbidity ( all ( ! wat] fl[+ (f is #j4eg z be=e1 b ! wat] tak5 = wat]-works purposes w consi/ ( #b volumes ( wat] ) turbidities ( #j4ib1 & #h volumes ) turbidities ( #j4aj mak+ #aj volumes ) an av]age turbidity ( #j4bf4 ,by d\bl+ ! l5g? ( ! wat]%$ we h ?us d\bl$ ! l5g? ( "t dur+ :i* ! wat] is turbid1 & h increas$ ! av]age turbidity ( ! wat] tak5 = wat]-works purposes f #j4ai to #j4bf1 al?\gh ! av]age turbidity ( all ! wat] runn+ (f rema9s exactly ! same4 ,if n[ we assume a wat]%$ s long t ?ree days are requir$ = ! wat] f ! mo/ remote po9ts to rea* ! intake1 ) computations z above1 wat] tak5 = wat]-works purposes w h an av]age turbidity ( #j4cb2 & ) /ill long] wat]%$s ?is am\nt w increase1 until ) a wat]%$ s long t t5 days1 or ! int]val betwe5 ra9s1 are requir$ = ! wat] f ! upp] portions to rea* ! intake1 ! av]age turbidity ( ! wat] tak5 = wat]-works purposes w rea* ! av]age turbidity ( ! run-(f1 namely1 #j4eg4 ,9 ! above computations ! numb]s tak5 are r\nd ones1 & ( c\rse d n repres5t closely actual conditions4 ,!y d s]ve1 h[ev]1 to illu/rate cle>ly ! pr9ciple t ! l>g] ! wat]%$1 o!r ?+s be+ equal1 ! m muddy w be ! wat] obta9$ f x = wat]-works purposes1 & ! long] w be ! p]iods ( muddy wat]1 & ! %ort] ! p]iods ( cle> wat] betwe5 !m4 ,x _c be too /rongly emphasiz$ t ! p]iod ( duration ( muddy wat] is1 9 g5]al1 dep5d5t ^u ! l5g? ( "t necess>y = ! muddy wat] to run out ( ! /ream sy/em aft] x is once 9 x1 & be replac$ by cle> wat]2 & t ! settl+ out ( ! mud 9 ! riv] has v little to d ) x4 ,muddy wat]s result pr9cipally f ! action ( ra9s ^u ! surface ( gr\nd capable ( be+ wa%$1 & ! turbidities ( ! /ream at any po9t bel[ w occur at ! times :5 ! muddy wat]s rea* x 9 ! natural c\rse ( fl[1 & w disappe> aga9 :5 ! muddy wat]s pres5t 9 ! /ream sy/em at ! end ( ! ra9 h run out1 & h be5 replac$ ) cle> wat] f und]gr\nd s\rces1 or f cle>] surface s\rces4 ,,! ,,am\nts ,,( ,,susp5d$ ,,matt]s ,,9 ,,wat]4 ,!re is a l>ge class ( wat]s1 includ+ mo/ lake & res]voir wat]s1 & surface-wat]s f c]ta9 geological =mations1 :i* are almo/ free f susp5d$ matt]s & turbidities4 ,t is to say1 ! av]age turbidities are less ?an #j4aj1 & ! av]age susp5d$ matt]s are less ?an #b p>ts 9 #ajj1jjj1 & are (t5 only small fractions ( ^! figures4 ,?is class includes ! raw wat]s ( ! supplies ( _m ,engli% cities drawn f imp\nd+ res]voirs1 & also ! wat]s ( ! riv]s ,?ames & ,lea at ,london1 & ! raw wat]s us$ by bo? ( ! ,b]l9 wat]-works1 & 9 ! ,unit$ ,/ates ! wat]s ( ! great lakes except at special po9ts ne> ! m\?s ( riv]s1 ne>ly all ,new ,engl& wat]s1 & _m o!r wat]s along ! ,atlantic coa/ & else:]e :]e ! geological =mations are favorable4 ,data reg>d+ ! susp5d$ matt]s 9 ^! wat]s are extremely meagre4 ,! (ficial exam9ations ( ! ,london wat]s conta9 no records ( susp5d$ matt]s1 al?\gh ! cle>ness ( filt]$ wat]s is daily report$4 ,dibd51 9 8 analytical inve/igations ( ! ,london wat]-supply1 m5tion$ 9 8 book ^u 8,! ,purification ( ,sewage & ,wat]10 reports ! av]age susp5d$ matt]s 9 ! wat] ( ! ,?ames ne> ! wat]-works intakes z #j4gg "p 9 #ajj1jjj4 ,no figures are available = ! raw wat]s us$ by ! ,b]l9 wat]-works1 b bo? are tak5 f lakes1 & are g5]ally q cle>4 ,ev5 9 times ( floods ( ! riv]s fe$+ ! lakes1 ! turbidities are n v high1 because ! ga!r+ gr\nds = ! wat]s are almo/ entirely ( a s&y nature1 yield+ wat]s ) l[ turbidities1 & fur!r1 ! /reams fl[ ?r\gh successions ( lakes be=e f9ally rea*+ ! lakes f :i* ! wat]s are tak54 ,x is safe to assume t ! susp5d$ matt]s & turbidities d n exce$ ^? ( ! ,london wat]s4 ,ev5 at times :5 some:at turbid wat] is obta9$1 due to agitation by heavy w9ds1 ! susp5d$ matt] is ma9ly ( a s&y nature1 readily remov$ by settl+1 & x does n s]i\sly int]f]e ) filtration4 ,! exam9ations ( ! ,massa*usetts ,/ate ,bo>d ( ,heal?1 ) a v few exceptions1 conta9 no /atem5ts ( susp5d$ matt]s4 ,?is is due to ! fact t ! susp5d$ matt]s1 9 mo/ ( ! wat]s1 are s small 9 am\nt z to make !m h>dly capable ( det]m9ation by ! ord9>y gravimetric processes1 & ! det]m9ations if made w\ld h b little value4 ,! ,m]rimac ,riv] at ,lawr5ce1 at ! "t ( ! greate/ flood 9 fifty ye>s1 c>ri$ silt to ! am\nt ( ab\t #aaa p>ts 9 #ajj1jjj4 ,?is 0 = a v %ort "t1 & ! susp5d$ matt] consi/$ almo/ entirely ( s&1 :i* deposit$ 9 banks1 ! deposit$ s& hav+ an effective size ( #j4jd or #j4je millimet]4 ,no clayey matt] is ev] c>ri$ 9 quantity by ! riv]4 ,! reports ( ! ,connecticut ,/ate ,bo>d ( ,heal? also conta9 no records ( susp5d$ matt]s = ! same reason4 ,x may be safely said t ! av]age susp5d$ matt]s ( ,new ,engl& wat]s are almo/ always less ?an #a "p 9 #ajj1jjj4 ,lake wat]s are g5]ally almo/ entirely free f s$im5t4 ,at ,*icago ! city wat] drawn f ,lake ,mi*igan has slightly m ?an #a "p 9 #ajj1jjj ( susp5d$ matt]s1 z det]m9$ by ,pr(essor ,long 9 #ahhh-i1 & by ,pr(essor ,palm] 9 #ahif4 ,! susp5d$ matt] 9 ?is case is probably due to ! ne>ness ( ! intake to ! m\? ( ! ,*icago ,riv]1 & to mud br\ght up f ! bottom 9 times ( /orms4 ,! lake-wat] fur!r away f ! %ore w\ld probably give mu* l[] results4 ,turn+ n[ to wat]s hav+ consid]able turbidities1 at ,pittsburg ! av]age susp5d$ matt]s 9 ! ,allegh5y ,riv] wat]1 z %[n by ! weekly or semi-weekly analyses ( ! ,filtration ,commission dur+ #ahig-h1 7 #d p>ts 9 #ajj1jjj4 ,dur+ a l>ge "p ( ! "t ! susp5d$ matt]s 7 s small t x 0 n deem$ wor? :ile to det]m9e !m1 & ! results are return$ z z]o4 ,?is is n q correct1 & a recomputation ( ! am\nt ( susp5d$ matt]s1 bas$ on ! obs]v$ am\nts1 & ! am\nts calculat$ f ! turbidities :5 !y 7 v l[1 leads to an av]age ( a little less ?an #e p>ts 9 #ajj1jjj1 :i* is probably m accurate ?an ! direct av]age4 ,! av]age turbidity on ! plat9um-wire scale 0 #j4af4 ,at ,c9c9nati ! susp5d$ matt]s are ab\t #bc p>ts 9 #ajj1jjj1 & at ,l\isville ab\t #ce p>ts1 bo? ( ^! figures be+ f ,mr4 ,full]'s reports4 ,9 all ^! cases ! enorm\s & rapid fluctuations 9 ! turbidity ( ! wat] is a mo/ /rik+ feature ( ! results4 ,obs]vations on ! ,mississippi ,riv] above ! ,ohio h be5 made by ,pr(essor ,long 9 #ahhh-i1 & by ,pr(essor ,palm] 9 #ahif4 ,^! results are n z full & sy/ematic z c\ld be desir$1 b indicate av]ages ( #bj to #cj p>ts 9 #ajj1jjj at ! diff]5t po9ts4 ,pr(essor ,william ,ripley ,ni*ols1 9 8 "w on wat]-supply1 /ates ! am\nt ( susp5d$ matt] 9 ! wat] ( ! ,mississippi1 probably ref]r+ to ! l[] riv]1 z #ff4ff p>ts4 ,inve/igations ( ,pr(essor ,long & ,pr(essor ,palm] = num]\s int]ior ,ill9ois /reams ext5d+ ov] consid]able p]iods give av]age results rang+ f #a to #h p>ts 9 #ajj1jjj4 ,! v mu* l[] results = ! int]ior /reams z comp>$ ) ! ,mississippi & ,ohio riv]s may be due to ! relative sizes & l5g?s ( ! /reams1 or 9 "p to o!r causes4 ,reg>d+ muddy ,european riv]s !re are b few data4 ,! ,maas1 us$ = ! wat]-supply ( ,rott]dam1 is report$ by ,pr(essor ,ni*ols z hav+ f #a4dj to #dg4fa & av]ag+ #aj p>ts ( susp5d$ matt]s 9 #ajj1jjj4 ,m rec5t in=mation is to ! effect t ! raw wat] has at mo/ #cj p>ts ( susp5d$ matt]s1 & t t quantity is v seldom rea*$4 ,at ,brem5 ! ,wes] (t5 becomes q turbid4 ,! turbidity ( ! wat] is not$ e day by tak+ ! dep? at :i* a black l9e on a :ite surface c be se54 ,assum+ t ?is proc$ure is equival5t to ! plat9um-wire proc$ure1 ! dep?s at :i* ! wire c be se51 namely1 f #ae to #fjj millimet]s1 correspond to turbidities ( f #j4jd to #a4gj1 a result n v diff]5t f ! conditions at ,pittsburg4 ,at ,hamburg & ,altona ! wat] is g5]ally tol]ably cle>1 b at times ( flood ! ,elbe becomes v turbid1 & ! am\nt ( mud deposit$ 9 ! s$im5tation-bas9s is consid]able4 ,at ,dresd51 sev]al hundr$ miles up ! riv]1 ,i h repeat$ly se5 ! riv]-wat] extremely turbid ) clayey matt]1 ! color ( ! clay v>y+ f day to day1 correspond+ to ! color ( ! e>? f :i* x _h be5 wa%$4 ,at ,budape/1 :]e filt]s 7 us$ tempor>ily1 ! ,danube wat] 0 excessively muddy ) clayey mat]ial4 ,at fir/ v high rates ( filtration 7 employ$ & ! results 7 n satisfactory4 ,aft]w>d ! rate ( filtration 0 limit$ to #a4jg million gallons p] acre daily1 & good results 7 secur$4 ,!re 0 no prelim9>y s$im5tation4 ,pr(essor ,ni*ols reports ! av]age susp5d$ matt]s 9 ! ,danube at #cb4fh p>ts 9 #ajj1jjj1 b does n /ate at :at place4 ,_m ( ! ,fr5* & ,g]man riv]s dra9 prairie c\ntry n diff]5t 9 its g5]al aspect f ! ,mississippi bas91 & ! soil is probably 9 _m places simil>4 ,!re is no reason to suppose t ! turbidities ( ^! /reams 9 g5]al are mat]ially diff]5t f ^? ( correspond+ /reams 9 ! ,unit$ ,/ates1 al?\gh x is true t1 o!r ?+s be+ equal1 ! av]age turbidity ( wat] tak5 = wat]-works purposes w increase ) ! size ( ! /ream2 & x may be t "s ,am]ican /reams1 especially ! ,ohio1 ,miss\ri1 & ,mississippi riv]s1 are ( l>g] size ?an ,european /reams1 & consequ5tly t ! turbidity ( ! wat] tak5 f !m = wat]-works purposes may be great]4 ,! foll[+ are ! dra9age areas ( a numb] ( ,european & ,am]ican /reams yield+ m or less muddy wat]s at po9ts :]e !y are us$ = public wat]-supplies aft] filtration1 ) a few o!r ,am]ican po9ts = comp>ison4 ,! results are obta9$ 9 mo/ cases f measurem5ts ( ! be/ available maps4 ---------------------------------------- --------------------- ,dra9age ,area1 ,place4 ,riv]4 ,squ>e ,miles4 ---------------------------------------- --------------------- ,new ,orleans1 ,la4 ,mississippi #a1bfa1jjj ,/4 ,l\is1 ,mo4 ,mississippi #gjj1jjj ,/4 ,pet]sburg ,neva #ajh1jjj ,l\isville1 ,ky4 ,ohio #ij1jjj ,rock ,isl&1 ,ill4 ,mississippi #hh1jjj ,budape/ ,danube #gi1jjj ,c9c9nati1 ,o4 ,ohio #ge1gjj ,dordre*t ,maas #fh1jjj ,rott]dam ,maas #fh1jjj ,s*i$am ,maas #fh1jjj ,altona ,elbe #eb1jjj ,hamburg ,elbe #eb1jjj ,/ett9 ,od] #dj1jjj ,magdeburg ,elbe #cf1jjj ,w>saw ,wei*sel #cd1jjj ,odessa ,dnei/] #bf1jjj ,worms ,rh9e #be1jjj ,gr& ,=ks1 ,n4 ,dak4 ,r$ ,riv] ( ! ,nor? #bb1jjj ,frank=t on ,od] ,od] #ba1jjj ,brem5 ,wes] #ae1jjj ,suburbs ( ,p>is ,se9e #ab1jjj ,p\ghkeepsie1 ,n4 ,y4 ,hudson #aa1fjj ,pittsburg1 ,p5n4 ,allegh5y #aa1djj ,pos5 ,w>?a #i1djj ,hudson1 ,n4 ,y4 ,hudson #i1bjj ,albany1 ,n4 ,y4 ,hudson #h1bjj ,breslau ,od] #h1bjj ,brieg ,od] #g1ejj ,lawr5ce1 ,mass4 ,m]rimac #d1fcd ,/uttg>t ,neck> #a1ffj ,brunswick ,ock] #fej ,som]swor?1 ,n4 ,h4 ,salmon #aga ---------------------------------------- --------------------- ,,prelim9>y ,,processes ,,to ,,remove ,,mud4 ,) bo? s& & me*anical filtration ! difficulty & exp5se ( treatm5t ( a wat] increase ne>ly 9 direct proportion to ! turbidity ( ! wat] z appli$ to ! filt]2 & x is ?us highly important to secure a wat] = filtration ) z little turbidity z possible1 & ?us to develop to _! economical limits ! prelim9>y processes = ! removal ( mud4 ,"o ( ! mo/ important ( ^! processes is ! use ( res]voirs4 ,res]voirs s]ve two purposes 9 connection ) wat]s drawn f /reams3 !y all[ s$im5tation1 & !y af=d /orage4 ,if a wat] hav+ a turbidity ( #a4jj is all[$ to rema9 9 a s$im5tation-bas9 = #bd h\rs1 its turbidity may be r$uc$ by z mu* z #dj p] c5t1 or to #j4fj4 ,if x is held a second day ! additional r$uction is mu* less4 ,if samples are tak5 ( ! wat] 9 ! res]voir be=e & aft] settl+ & s5t to ! *emi/ = analysis1 he w probably report t f #gj to #hj p] c5t ( ! susp5d$ matt]s h be5 remov$ by ! process4 ,! susp5d$ matt]s are remov$ 9 mu* l>g] ratio ?an ! turbidity4 ,?is arises f ! fact t !re is a c]ta9 proportion ( comp>atively co>se mat]ial 9 ! wat] z x is tak5 f ! riv]4 ,?is co>se mat]ial increases ! weight ( ! susp5d$ matt]s )\t increas+ ! turbidity 9 a correspond+ degree4 ,9 #bd h\rs ! co>s] mat]ials are remov$ completely1 & at ! end ( t "t only ! clayey or f9] p>ticles rema9 9 susp5sion4 ,x is ^! clayey p>ticles1 h[ev]1 t con/itute ! turbidity1 :i* are mo/ objectionable 9 appe>ance1 & :i* are mo/ difficult ( removal by filtration or o!rwise4 ,s$im5tation ?us removes ! heavi] matt]s f ! wat]1 b x does n remove ! f9] matt]s :i* pr9cipally affect ! appe>ance ( ! wat] & are o!rwise mo/ tr\blesome4 ,a s$im5tation ( #bd h\rs removes practically all ( ! co>s] matt]s1 & ! clayey mat]ial rema9+ at ! end ( t "t c h>dly be remov$ by fur!r s$im5tation4 ,! economic limit ( s$im5tation is ab\t #bd h\rs4 ,s$im5tation has practically no effect ^u ! cle>] wat]s betwe5 flood p]iods4 ,let u consid] ! effect ( a s$im5tation-bas91 or res]voir hold+ a #bd-;h\rs' supply ( wat]1 into :i* wat] is con/antly pump$ at "o end1 & f :i* an equal quantity is con/antly )drawn f ! o!r1 ^u ! wat] ( a /ream ( su* size t ! "t ( passage ( wat] f ! fe$]s to ! intake is less ?an #bd h\rs4 ,dur+ ! p]iod betwe5 /orms ! wat] is comp>atively cle> & passes ?r\gh ! s$im5tation bas9 )\t *ange4 ,:5 a /orm comes ! wat] 9 ! /ream promptly becomes muddy1 & muddy wat] is suppli$ to ! res]voir2 b ow+ to ! "t requir$ = wat] to pass ?r\gh x1 ! outfl[+ wat] rema9s cle> = "s h\rs4 ,!re is a gradual mix+1 h[ev]1 & long be=e ! expiration ( #bd h\rs some:at muddy wat] appe>s at ! outlet4 ,! turbid-wat] p]iod r>ely la/s 9 /reams ( ?is size m ?an #bd h\rs1 & at ! expiration ( t "t ! wat] 9 ! s$im5tation-bas9 is z muddy or muddi] ?an ! wat] fl[+ 9 ! /ream4 ,aft] ! height ( ! flood ! /ream cle>s itself by ! fl[+ away ( ! turbid wat] mu* m rapidly ?an ! wat] cle>s itself by s$im5tation 9 ! res]voir4 ,t is to say1 if at ! "t ( maximum turbidity we take a c]ta9 quantity ( wat] f ! /ream & put x aside to settle1 at no "t w ! improvem5t by settl+ equal ! improvem5t :i* has tak5 place 9 ! /ream f natural causes4 ,g5]ally ! improvem5t 9 ! /ream is sev]al times z rapid z 9 ! s$im5tation-bas91 & ! wat] f x w at times h only a fraction ( ! turbidity ( ! wat] 9 ! bas94 ,let u n[ consid] :at ! s$im5tation has done to improve ! wat]4 ,dur+ ! p]iod ( cle> wat]1 t is = mo/ ( ! "t1 x has done no?+4 ,= ! fir/ day ( ea* flood p]iod v mu* cle>] wat] has be5 obta9$ f x ?an 0 fl[+ 9 ! /ream4 ,= ! fir/ days foll[+ floods ! wat] 9 ! s$im5tation-bas9 has be5 m muddy ?an ! wat] 9 ! /ream4 ,! only "t :5 ! s$im5tation-bas9 has be5 ( use is dur+ ! fir/ "p ( floods1 t is1 :5 ! turbidity ( ! wat] 9 ! /ream is increas+4 ,dur+ ?is p]iod x has be5 ( s]vice pr9cipally because ( its /orage capacity1 yield+ up wat] receiv$ f ! /ream previ\sly1 :5 x 0 less muddy4 ,su* s$im5tation z has be5 secur$ is m]ely incid5tal & g5]ally n important 9 am\nt4 ,x w be obvi\s f ! above t = ^! conditions /orage is mu* m important ?an s$im5tation4 ,?is br+s u back to ! old ,engli% idea ( hav+ /orage-res]voirs l>ge en\gh to c>ry wat]-works ov] flood p]iods )\t ! use ( flood-wat]s4 ,res]voirs ( ?is k9d 71 & /ill are1 consid]$ necess>y = ! successful utilization ( wat]s ( _m ,engli% riv]s1 al?\gh ^! wat]s d n approa* 9 turbidity ! wat]s ( "s ,am]ican /reams4 ,?is idea ( /orage has be5 b little us$ 9 ! ,unit$ ,/ates4 ,9 ! above case1 if we use our res]voir = /orage in/ead ( z a s$im5tation-bas91 ! av]age quality ( ! wat] c be greatly improv$4 ,! res]voir %\ld ord9>ily be kept full1 & pump+ to x %\ld be /opp$ :5ev] ! turbidity exce$s a c]ta9 limit1 to be det]m9$ by exp]i5ce2 & ! res]voir is !n to be drawn ^u = ! supply until ! turbidity aga9 falls to ! normal4 ,9 ! case assum$ above1 ) a /ream 9 :i* all ( ! wat] rea*es ! intake 9 #bd h\rs1 a res]voir hold+ a #bd-;h\rs' supply1 or 9 practice1 to be safe1 a some:at l>g] "o1 w\ld yield a wat] hav+ a v mu* l[] av]age turbidity ?an w\ld be obta9$ ) wat] pump$ con/antly f ! /ream )\t a res]voir4 ,) a riv] hav+ a wat]%$ s long t #dh h\rs are requir$ to br+ ! wat] d[n f ! mo/ remote fe$]s1 a res]voir twice z l>ge w\ld be requir$1 & w\ld result 9 a /ill great] r$uction 9 ! av]age turbidity4 ,z ! /ream becomes l>g]1 & ! turbid p]iods long]1 ! size ( a res]voir necess>y to utilize ?is action rapidly becomes l>g]1 & ! times dur+ :i* x c be fill$ are %ort5$1 & ?us ! eng9e]+ difficulties ( ! problem are increas$4 ,= mod]ately %ort /reams1 co/ = co/1 /orage is f> m effective ?an s$im5tation1 & we mu/ come back to ! old ,engli% practice ( /opp+ our pumps dur+ p]iods ( maximum turbidity4 ,,effect ,,( ,,mud ,,^u ,,s& ,,filt]s4 ,!re are two aspects ( ! effect ( mud ^u ! op]ation ( s& filt]s :i* require p>ticul> consid]ation4 ,! fir/ relates to ! rapidity ( clogg+1 & consequ5tly ! frequ5cy ( scrap+ & ! co/ ( op]ation2 :ile ! second relates to ! ability ( ! filt]s to yield well-cl>ifi$ efflu5ts4 ,,effect ,,( ,,turbidity ,,^u ,,! ,,l5g? ,,( ,,p]iod4 ,! am\nt ( wat] :i* c be filt]$ betwe5 scrap+s is directly dep5d5t ^u ! turbidity ( ! raw wat]4 ,! great] ! turbidity1 ! m frequ5tly w filt]s require to be scrap$4 ,9 ! exp]im5ts ( ! ,pittsburg ,filtration ,commission1 ) #d feet ( s& ( an effective size ( ab\t #j4cj millimet]1 & ) rates ( filtration ( ab\t ?ree million gallons p] acre daily1 & ) ! loss ( head limit$ to #d feet1 s& filt]s 7 op]at$ z foll[s3 ,= five p]iods ! turbidities ( ! raw wat] rang$ f #j4jce to #j4jfb1 & av]ag$ #j4jea1 & ! correspond+ p]iods rang$ f #ajb to #acf1 & av]ag$ #aac million gallons p] acre filt]$ betwe5 scrap+s4 ,= t5 p]iods ! turbidities ( ! raw wat] rang$ f #j4jgi to #j4abh1 & av]ag$ #j4ajb1 & ! p]iods av]ag$ #gh million gallons p] acre betwe5 scrap+s4 ,= fifte5 o!r p]iods ! turbidities ( ! raw wat] rang$ f #j4acd to #j4bfi1 & av]ag$ #j4aie1 & ! p]iods av]ag$ #eb million gallons p] acre betwe5 scrap+s4 ,9 two o!r p]iods ! turbidities ( ! raw wat] av]ag$ #j4fg1 & ! p]iods betwe5 scrap+s av]ag$ #af million gallons4 ,9 all cases ! turbidity is tak5 z t ( ! wat] appli$ to ! filt]4 ,usually ?is 0 ! turbidity ( ! settl$ wat]1 b 9 "s cases raw wat] 0 appli$1 & 9 ^! case ! turbidity ( ! raw wat] is tak54 ,^! results are approximately repres5t$ by ! =mula ,p]iod betwe5 scrap+s1 #ab_/7turbidity #j4je74 million gallons p] acre ,except = v cle> wat]s ! am\nt ( wat] pass$ betwe5 scrap+s is ne>ly inv]sely proportional to ! turbidity4 ,) twice z great an am\nt ( turbidity1 filt]s w h to be clean$ twice z (t51 ! res]ve area = clean+ w require to be twice z great1 & ! co/ ( scrap+ filt]s & ( wa%+ & replac+ s&1 :i* is ! mo/ important elem5t 9 ! co/ ( op]ation1 w be d\bl$4 ,) wat]s hav+ turbidities ( #j4bj ^u ?is basis1 ! av]age p]iod w be ab\t #ea million gallons p] acre betwe5 scrap+s4 ,?is is ab\t ! av]age result obta9$ at ! ,g]man works filt]+ riv] wat]s1 & !re is no s]i\s difficulty 9 op]at+ filt]s :i* require to be scrap$ ) ?is frequ5cy4 ,) m turbid wat]s ! p]iod is decreas$4 ,) an av]age turbidity ( #j4ej ! av]age p]iod is only #bd million gallons p] acre betwe5 scrap+s1 a condition :i* means v difficult op]ation & a v high co/ ( clean+4 ,) mu* m turbid wat]s ! difficulties are increas$1 & if ! duration ( turbid wat] %\ld be long-cont9u$1 ! op]ation ( s& filt]s w\ld cle>ly be impracticable1 & ! exp5se1 also1 w\ld be prohibitive4 ,9 apply+ ^! figures to actual cases x mu/ be borne 9 m9d t ! turbidity is only "o ( ! sev]al factors :i* control ! l5g? ( p]iod2 & t ! turbidity ( a wat] ( a giv5 /ream is nev] con/ant1 b fluctuates )9 wide limits2 & t raw wat] c be appli$ to filt]s = a %ort "t )\t injuri\s results1 ev5 ?\gh x is s turbid t its cont9u$ application w\ld be fatal4 ,x is v likely also t ! susp5d$ matt]s 9 diff]5t /reams diff] 9 _! natures to su* an ext5t t equal turbidities w\ld give q diff]5t p]iods1 al?\gh ! ,pittsburg results 7 s regul> z to give confid5ce 9 _! application to o!r conditions )9 reasonable limits1 & :5 s appli$ !y af=d a mo/ conv5i5t me?od ( comput+ ! approximate co/ ( op]ation ( filt]s = wat]s ( kn[n or e/imat$ turbidities4 ,,p[] ,,( ,,s& ,,filt]s ,,to ,,produce ,,cle> ,,efflu5ts ,,f ,,muddy ,,wat]4 ,:5 ! turbidity ( ! appli$ wat] is n too great x is entirely remov$ 9 ! c\rse ( filtration4 ,) extremely muddy raw wat]s1 h[ev]1 turbid efflu5ts are (t5 produc$ ) s& filt]s4 ,! conditions :i* control ! passage ( ! f9e/ susp5d$ matt]s ?r\gh filt]s h be5 /udi$ by ,mr4 ,full] at ,c9c9nati at consid]able l5g?4 ,!y are simil> 9 a g5]al way to ! conditions :i* control ! removal ( bact]ia4 ,t is to say1 ! removal is m complete ) f9e filt] s& ?an ) co>se s&2 ) a deep s& lay] ?an ) a %all[ s& lay]2 & ) l[ rates ( filtration ?an ) high rates4 ,! practicable limits to ! size ( s& gra91 dep? ( s& lay]1 & rate ( filtration are e/abli%$ by o!r conditions1 & ! "q rema9s :e!r )9 ^! limits a cle> efflu5t c be produc$4 ,at ,pittsburg ! turbidity ( ! efflu5t f a s& filt] op]at$ z m5tion$ above1 :i* receiv$ wat] :i* _h pass$ ?r\gh a s$im5tation-bas9 hold+ ab\t a #bd-;h\rs' supply1 b )\t tak+ any advantage ( /orage to avoid ! use ( muddy wat]1 0 ne>ly always less ?an #j4jb1 :i* may be tak5 z ! admissible limit ( turbidity 9 a public wat]-supply4 ,?is limit 0 exce$$ on less ?an #bj days out ( #cfe1 ^! days be+ dur+ ! w9t] & spr+ fre%ets1 & on ^! days ! excess 0 n su* z w\ld be likely to be p>ticul>ly objectionable4 ,= ! wat] ( ! ,allegh5y ,riv]1 !n1 s& filtration ) "o day's s$im5tation is capable ( yield+ a wat] n absolutely cle>1 b suffici5tly cle> to be q satisfactory = ! purpose ( municipal wat]-supply4 ,at ,c9c9nati1 on ! o!r h&1 :]e ! am\nt ( susp5d$ matt]s 0 five times z great z at ,pittsburg1 ! efflu5ts :i* c\ld be obta9$ by s& filtration )\t rec\rse to ! use ( alum1 ev5 "u mo/ favorable conditions1 7 v mu* m turbid ?an ^? obta9$ at ,pittsburg1 & 71 9 fact1 s turbid z to be s]i\sly objectionable = ! purpose ( public wat]-supply4 ,) riv]s no m turbid ?an ! ,allegh5y ,riv] at ,pittsburg1 & riv]s hav+ floods ( su* %ort duration t ! use ( flood-fl[s c be avoid$ by ! use ( res]voirs1 s& filt]s are adequate = cl>ification4 ,= wat]s :i* are mu* muddi] ?an ! ,allegh5y1 z1 = in/ance1 ! ,ohio at ,c9c9nati & at ,l\isville1 s& filtration alone is inadequate4 ,mr4 ,full]1#ca z a result ( 8 ,c9c9nati exp]im5ts1 has /at$ ! case z foll[s3 8,= ! sake ( explicitness x is desir$ to %[1 ) ! data ( ! fairly normal ye> ( #ahih1 ! proportion ( ! "t :5 ,engli% filt]s 7t is1 s& filt]s7 w\ld be inapplicable 9 ! purification ( ! unsubsid$ ,ohio ,riv] wat] at ,c9c9nati4 ,?is necessitates fix+ an av]age limit ( p]missible susp5d$ matt] 9 ?is riv] wat]1 & is a difficult matt] f pres5t evid5ce4 8,9 "p ?is is due to v>iations 9 ! "* & 9 ! relative am\nts ( ! susp5d$ silt1 clay1 & organic matt]2 & 9 "p x is due to diff]5t am\nts ( clay /or$ 9 ! s& lay]1 :i* affects mat]ially ! capacity ( ! filt] to reta9 ! clay ( ! appli$ wat]4 ,dur+ ^! inve/igations ! unsubsid$ riv]-wat] 0 n regul>ly appli$ to filt]s2 &1 ) ! exception ( ! results ( te/s = a few days only1 x is necess>y to dep5d ^u g5]al in=mation obta9$ ) ref]5ce to ?is po9t4 ,s f> z ! in=mation goes1 x appe>s t an av]age ( #abe p>ts p] million is a cons]vative e/imate ( ! am\nt ( susp5d$ matt]s 9 ! unsubsid$ riv]-wat]1 :i* c\ld be regul>ly & satisfactorily h&l$ by ,engli% filt]s4 ,b at times ?is e/imat$ av]age w\ld be too l[1 & at o!r times too high4444 8,:ile ,engli% filt]s are able to remove satisfactorily on an av]age ab\t #abe p>ts ( silt & clay ( ! unsubsid$ wat]1 actual exp]i5ce %[s t !y c regul>ly h&le susp5d$ clay 9 subsid$ wat] 9 am\nts rang+ only z high z f #cj to #gj p>ts 7dep5d+ ^u ! am\nt ( ! clay /or$ 9 ! s& lay]71 & av]ag+ ab\t #ej p>ts p] million4 ,b x is true t = two or ?ree days on %ort rises 9 ! riv]1 or at ! beg9n+ ( long fre%ets1 ! ret5tive capacity ( ! s& lay] all[s ( satisfactory results ) ! clay 9 ! appli$ wat] consid]ably 9 excess ( #gj p>ts4 ,if ?is capacity is greatly ov]tax$1 h[ev]1 ! advantage is m]ely tempor>y1 z ! /or$ clay is wa%$ out lat]1 produc+ m>k$ly turbid efflu5ts40 ,translat+ ,mr4 ,full]'s results into t]ms ( turbidity1 ! #abe p>ts p] million ( susp5d$ matt]s 9 ! raw wat] repres5t a turbidity ( ab\t #j4dj1 & ! #cj to #gj p>ts ( susp5d$ matt]s 9 ! settl$ wat] repres5t turbidities f #j4bj to #j4dj1 ! av]age ( #ej p>ts ( susp5d$ matt]s correspond+ to a turbidity ( ab\t #j4cj4 ,^u ?is basis1 !n1 s& filt]s are capable ( treat+ raw wat]s ) av]age turbidities up to #j4dj1 or settl$ wat]s ) av]age turbidities up to #j4cj1 b wat]s m turbid ?an ?is are incapable ( be+ successfully treat$ )\t ! use ( coagulants or o!r aids to ! process4 ,^! results are 9 g5]al accordance ) ! results ( ! exp]im5ts at ,pittsburg1 & demon/rate t :ile s& filt]s z g5]ally us$ 9 ,europe are adequate = ! cl>ification ( _m1 if n mo/1 riv] wat]s 9 ! ,unit$ ,/ates1 !re are o!r wat]s c>ry+ mud 9 su* quantities z to make ! process inapplicable to !m4 ,,effect ,,( ,,mud ,,^u ,,bact]ial ,,effici5cy ,,( ,,filt]s4 ,! "q is naturally rais$ z to :e!r or n ! pres5ce ( l>ge quantities ( mud 9 ! raw wat] w n s]i\sly int]f]e ) ! bact]ial effici5cy ( filt]s4 ,exp]im5ts at ,c9c9nati & ,pittsburg h giv5 mo/ conclusive & satisfactory in=mation ^u ?is po9t4 ,up to ! po9t :]e ! efflu5ts become q turbid1 ! mud 9 ! raw wat] has no influ5ce ^u ! bact]ial effici5cy2 & ev5 some:at beyond ?is po9t1 ) efflu5ts s turbid t !y w\ld h>dly be suitable = ! purpose ( a public wat]-supply1 ! bact]ial effici5cy rema9s sub/antially equal to t obta9$ ) ! cle>e/ wat]s4 ,only 9 ! case ( excessive quantities ( mud1 :]e1 = o!r reasons1 s& filt]s c h>dly be consid]$ applicable1 is !re a mod]ate r$uction 9 bact]ial effici5cy4 ,z m5tion$ above1 p>ticles con/itut+ turbidity are (t5 mu* small] ?an ! bact]ia1 & 9 addition1 ! bact]ia probably h an adhesive p[] f> 9 excess ( t ( ! clay p>ticles4 ,= ^! reasons clay p>ticles are able to pass filt]s "u conditions :i* almo/ entirely prev5t ! passage ( bact]ia4 ,on ! o!r h&1 x does n necess>ily foll[ t ! removal ( turbidity is accompani$ by high bact]ial effici5cy4 ,al?\gh ?is is (t5 ! case1 !re are m>k$ exceptions1 p>ticul>ly 9 connection ) ! use ( coagulants1 :]e v good cl>ification is obta9$1 & not)/&+ ?is1 efflu5ts are produc$ conta9+ comp>atively l>ge numb]s ( bact]ia4 ,,limits ,,to ,,! ,,use ,,( ,,subsid5ce ,,= ,,! ,,prelim9>y ,,treatm5t ,,( ,,muddy ,,wat]s4 ,:5 wat] is too muddy to be appli$ directly to filt]s1 ! mo/ obvi\s treatm5t is to remove z mu* ( ! s$im5t z possible by s$im5tation4 ,s$im5tation-bas9s are consid]$ z ess5tial p>ts ( filtration plants = ! treatm5t ( muddy wat]s4 ,! effect ( s$im5tation1 z not$ above1 is to remove pr9cipally ! l>g] p>ticles 9 ! raw wat]4 ,by do+ ?is ! deposit ^u ! surface ( ! filt]s & ! co/ ( op]ation are greatly r$uc$4 ,^! l>g] p>ticles are ma9ly remov$ by a comp>atively %ort p]iod ( s$im5tation1 & ! improvem5t effect$ aft] ! fir/ #bd h\rs is comp>atively slight4 ,! p>ticles rema9+ 9 susp5sion at ! end ( ?is "t consi/ almo/ entirely ( v f9e clay1 & ! rate ( _! settlem5t ?r\gh ! wat] is extremely sl[2 & curr5ts 9 ! bas91 due to temp]ature *anges1 w9ds1 etc41 almo/ entirely (fset ! natural t5d5cy ( ! s$im5t to fall to ! bottom4 ,!re is ?us a practical limit to ! effect ( s$im5tation :i* is soon rea*$1 & x has n be5 f\nd feasible to ext5d ! process s z to all[ mu* m turbid wat]s to be br\ght )9 ! range :i* c be economically treat$ by s& filtration4 ,,*apt] ,,ix4 ,,! ,,coagulation ,,( ,,wat]s4 ,! coagulation ( wat] consi/s 9 ! addition to x ( "s sub/ance :i* =ms an inorganic precipitate 9 ! wat]1 ! pres5ce ( :i* has a physical action ^u ! susp5d$ matt]s1 & all[s !m to be m readily remov$ by subsid5ce or filtration4 ,! mo/ common coagulant is sulphate ( alum9a4 ,:5 ?is sub/ance is add$ to wat] x is decompos$ into its compon5t p>ts1 sulphuric acid & alum9a1 ! =m] ( :i* comb9es ) ! lime or o!r base pres5t 9 ! wat]1 or 9 case en\gh ( ?is is lack+1 x rema9s p>tly z free acid & p>tly undecompos$ 9 its orig9al condition2 :ile ! alum9a =ms a gelat9\s precipitate :i* draws toge!r & surr\nds ! susp5d$ matt]s pres5t 9 ! wat]1 includ+ ! bact]ia1 & all[s !m to be mu* m easily remov$ by filtration ?an w\ld o!rwise be ! case4 ,9 addition1 ! alum9a has a *emical attraction = dissolv$ organic matt]s1 & ! *emical purification may be m complete at v high rates ?an w\ld be possible ) s& filtration )\t coagulant at any rate1 h[ev] l[4 ,coagulants h be5 employ$ 9 connection ) filtration f v e>ly times4 ,z e>ly z #ahca ,d',arcet publi%$ 9 ! 8,annales d'hygine publique10#cb an acc\nt ( ! purification ( ,nile wat] 9 ,egypt by add+ alum to ! wat]1 & aft]w>ds filt]+ x ?r\gh small h\sehold filt]s4 ,m rec5tly alum has be5 repeat$ly us$ 9 connection ) s& filt]s1 p>ticul>ly at ,leeuw>d51 ,gron+51 & ,s*i$am 9 ,holl&1 :]e ! riv] wat]s us$ = public supplies are color$ by peaty matt] :i* _c be remov$ by simple filtration4 ,,sub/ances ,,us$ ,,= ,,coagulation4 ,mr4 ,full]#cc has giv5 a v full acc\nt ( ! sub/ances :i* c be us$ = ! cl>ification ( wat]s4 ,)\t tak+ up all ( ! unusual sub/ances :i* h be5 sugge/$1 ! mo/ important ( ! coagulants w be briefly describ$ bel[4 ,lime4--,lime has be5 ext5sively us$ 9 connection ) ! purification ( sewage1 & also = s(t5+ wat]4 ,lime is fir/ slak$ & conv]t$ into calcium hydrate1 :i* is aft]w>ds dissolv$ 9 wat]1 & appli$ to ! wat] "u treatm5t4 ,! am\nt ( lime to be us$ is fix$ by ! am\nt ( c>bonic acid 9 ! wat]4 ,s mu* lime is always us$ z w exactly conv]t ! :ole ( ! c>bonic acid ( ! wat] into normal c>bonate ( lime4 ,?is sub/ance is b slightly soluble 9 wat] & x precipitates4 ,! precipitate is cry/all9e r ?an floccul5t1 & is n z well adapt$ to aid 9 ! removal ( clayey matt]s z "s o!r sub/ances1 al?\gh its action 9 ?is respect is consid]able4 ,! precipitate is q heavy1 & is l>gely remov$ by s$im5tation1 al?\gh filtration mu/ be us$ to complete ! process4 ,wat] :i* has be5 treat$ ) lime is slightly cau/ic2 t is to say1 !re is a defici5cy ( c>bonic acid 9 x1 & x deposits lime 9 ! pipes1 9 pumps1 etc42 & al?\gh ! precipitat$ calcium c>bonate is mu* s(t] ?an /eel1 x rapidly de/roys pumps us$ = lift+ x4 ,pr9cipally = ^! reasons x is necess>y to supply c>bonic acid to wat] :i* has be5 treat$ 9 ?is way1 & ?is is done by br++ x 9 contact ) flue-gases1 or by ! direct addition ( c>bonic acid4 ,! use ( lime = s(t5+ wat]s is kn[n z ,cl>k's process4 ,x 0 pat5t$ 9 ,engl& _m ye>s ago1 & ! pat5t has n[ expir$4 ,v>i\s +5i\s devices h be5 con/ruct$ = facilitat+ v>i\s p>ts ( ! op]ation4 ,! process has h>dly be5 us$ 9 ! ,unit$ ,/ates1 b !re is a l>ge field = x 9 connection ) ! s(t5+ ( v h>d wat]s1 & :]e su* wat]s also conta9 iron or clay1 ^! sub/ances w be incid5tally remov$ by ! process4 ,l>g] quantities ( lime h an action ^u ! susp5d$ matt]s :i* is entirely diff]5t f t secur$ 9 ,cl>k's process1 & ! action ^u bact]ia is p>ticul>ly notewor?y4 ,?is action 0 not$ 9 exp]im5ts at ,lawr5ce1#cd :]e x 0 f\nd t sewage 0 almo/ completely /]iliz$ by ! application ( consid]able quantities ( lime4 ,an extremely int]e/+ s]ies ( exp]im5ts ^u ! application ( l>ge quantities ( lime to wat] 0 made by ,mr4 ,full] 9 #ahii4ce ,! bact]ial results 7 extremely favorable1 al?\gh ! necessity = remov+ ! excess ( lime aft]w>d is a some:at s]i\s matt]1 & 9 ^! exp]im5ts x 0 n entirely accompli%$4 ,alum9um ,comp\nds4--,sulphate ( alum9a is mo/ commonly employ$4 ,x c be obta9$ 9 a /ate ( consid]able purity at a v mod]ate price1 & important improvem5ts 9 ! me?ods us$ = its manufacture h be5 rec5tly introduc$4 ,pota% & soda alums h no advantage ov] sulphate ( alum9a1 &1 9 fact1 are less effici5t p] p\nd1 :ile _! co/s are great]4 ,*loride ( alum9a is practically equival5t to ! sulphate 9 purify+ p[]1 b is m exp5sive4 ,sodium ,alum9ate has be5 exam9$ by ,mr4 ,full]1 :o /ates t exp]i5ce has %[n t its use is impracticable 9 ! case ( ! ,ohio ,riv] wat]4 ,comp\nds ( ,iron4--,iron =ms two classes ( comp\nds1 namely1 f]r\s & f]ric salts4 ,:5 ! f]r\s salts are appli$ to wat]1 "u c]ta9 conditions1 f]r\s hydrate is precipitat$1 b ?is sub/ance is n entirely insoluble 9 wat] conta9+ c>bonic acid4 ,"u "s conditions ! precipitat$ f]r\s hydrate is oxidiz$ by oxyg5 pres5t 9 ! wat] to f]ric hydrate1 & s f> z ?is is ! case1 good results c be obta9$4 ,f]r\s sulphate is n z readily oxidiz$ :5 appli$ to wat] z is ! f]ric c>bonate pres5t 9 _m natural wat]s1 & = ?is reason f]r\s sulphate has n be5 successfully us$ 9 wat] purification4 ,9 ! treatm5t ( sewage1 :]e ! requirem5ts are some:at diff]5t1 x has be5 "o ( ! mo/ satisfactory coagulants4 ,f]ric sulphate acts 9 mu* ! same way z sulphate ( alum9a1 & is entirely suitable = use :]e sulphate ( alum9a c\ld be employ$1 b x has n be5 us$ 9 practice1 due probably to its increas$ co/ z comp>$ ) its effect1 & to ! practical difficulties ( apply+ x 9 ! desir$ quantities due to its physical condition4 ,metallic ,iron3 ,! ,&]son ,process4--,! use ( metallic iron = wat] purification 9 connection ) a mod]ately sl[ filtration ?r\gh filt]s ( ! usual =m is kn[n z ,&]son's process 7pat5t$71 & has be5 us$ at ,antw]p & else:]e on a l>ge scale1 & has be5 exp]im5tally exam9$ at a numb] ( o!r places4 ,! process consi/s 9 agitat+ ! wat] 9 contact ) metallic iron1 a portion ( :i* is tak5 into solution z f]r\s c>bonate4 ,^u subsequ5t a]ation ?is is suppos$ to become oxidiz$ & precipitate out z f]ric hydrate1 ) all ! good & none ( ! bad effects :i* foll[ ! use ( alum4 ,! precipitate is p>tially remov$ by s$im5tation1 :ile filtration completes ! process4 ,! process is admirable !oretically1 & 9 an exp]im5tal way ^u a v small scale (t5 gives mo/ satisfactory results1 muddy wat]s v difficult ( filtration1 & color$ peaty wat]s yield+ promptly cle> & colorless efflu5ts4 ,9 apply+ ! process on a l>g] scale1 h[ev]1 ) peaty wat]s at lea/1 x seems impossible to get en\gh iron to g into solution 9 ! "t :i* c be all[$1 & ! small quantity :i* is tak5 up ei!r rema9s 9 solution or else sl[ly & incompletely precipitates out1 )\t ! good effects :i* foll[ ! sudd5 & complete precipitation ( a l>g] quantity1 & 9 ?is case ! color is seldom r$uc$1 & may ev5 be increas$ above ! color ( ! raw wat] by ! iron rema9+ 9 solution4 ,! +5uity ( ^? :o h /udi$ ! process has n yet f\nd any adequate means ( avoid+ ^! important practical objections2 & ev5 at ,antw]p a great ext5sion ( ! filt]+ area1 z well z ! use ( alum at times ( unusual pollution1 is good evid5ce t simple filtration1 9 di/9ction f ! effect ( ! iron1 is reli$ ^u mu* m ?an =m]ly4 ,at ,dordre*t also1 :]e ! process has be5 long 9 use1 ! rate ( filtration does n exce$ ! ord9>y limits2 nor is ! result1 s f> z ,i c\ld asc]ta91 9 any way sup]ior to t obta9$ a few miles away at ,rott]dam1 by ord9>y filtration1 ) sub/antially ! same raw wat]4 ,! results obta9$ at ,b\logne-sur-,se9e1 ne> ,p>is1 h be5 closely wat*$ by ! public *emi/ & bact]iologi/ ( ,p>is1 & h be5 v favorable1 & a numb] ( new plants ( v consid]able capacity h be5 built1 to supply "s ( ! suburbs ( ,p>is1 b ev5 9 ^! cases only mod]ate rates ( filtration are employ$ :i* w\ld yield excell5t efflu5ts )\t ! iron4 ,comp\nds ( ,manganese4--,manganese =ms comp\nds simil> to ^? ( iron1 t is to say mangan\s & manganic salts1 b _! use 9 connection ) wat] filtration has n be5 f\nd possible4 ,9 addition1 manganese =ms a s]ies ( comp\nds1 kn[n z manganates & p]manganates1 q diff]5t 9 _! /ructure & action f ! o!rs4 ,^! comp\nds conta9 an excess ( oxyg5 :i* !y give up v readily to organic matt]s capable ( absorb+ oxyg51 & because ( ?is p[]1 !y h be5 ext5sively us$ 9 ! treatm5t ( sewage4 ,appli$ to ! treatm5t ( wat]s _! action is v slight1 & ! comp\nds are s exp5sive t !y h n be5 employ$ = ?is purpose4 ,!oretically ! action is v attractive1 z ! oxyg5 lib]at$ by _! decomposition oxidizes "s ( ! organic matt] ( ! wat]1 !reby purify+ x 9 "p1 :ile ! manganese is precipitat$ z a floccul5t precipitate hav+ all ( ! advantages p]ta9+ to a precipitate ( hydrate ( alum9a1 & )\t ! disadvantage ( add+ acid to ! wat]1 z is ! case ) ! comp\nds ( alum9a & iron4 ,^! *emicals1 :5 us$ 9 comp>atively conc5trat$ condition1 h p[]ful g]micidal actions1 b 9 wat] purification ! am\nts :i* c be us$ are s small t no action ( ?is k9d results4 ,! am\nt :i* c be appli$ to a wat] is limit$ to ! am\nt :i* c be decompos$ by ! organic matt]s pres5t 9 ! wat]1 & is n l>ge4 ,! ,use ( ,metallic ,iron & ,alum9um1 ) ! ,aid ( ,electricity4--,elaborate exp]im5ts 7 made at ,l\isville ) metallic iron & alum9um oxidiz$ & made available by ! aid ( electric curr5ts4 ,! use ( iron ) electric curr5ts 0 tri$ 9 sewage purification "s ye>s ago1 "u ! "n ( ! ,web/] process1 b 0 nev] put to practical use4 ,! !ory is to oxidize ! iron or alum9um 9 contact ) ! wat]1 ) ! =mation ( floccul5t hydrates1 by ! aid ( an electric curr5t1 !reby secur+ ! advantages ( ! application ( salts ( ^! metals to ! wat] )\t ! disadvantage ( ! addition ( acid4 ,o!r ,*emicals ,employ$4--,a solution conta9+ *lor9e produc$ by electrical action has be5 sugge/$4 ,*lor9e is a p[]ful dis9fectant1 & :5 us$ 9 l>ge quantities kills bact]ia4 ,x is n possible to use en\gh *lor9e to kill ! bact]ia 9 ! wat] )\t r5d]+ x unfit = human use4 ,! nature ( ?is treatm5t has be5 concisely describ$ by ,dr4 ,dr[n1#cf :o %[s t ! electrically prep>$ fluids d n diff] 9 _! action 9 any way f well-kn[n *emicals1 ! use ( :i* w\ld be h>dly consid]$4 ,! use ( ozone & p]oxide ( hydrog5 h also be5 sugge/$1 b ,i d n "k t !y h be5 successfully us$ on a l>ge scale4 ,! same is true ( _m o!r *emicals1 ! consid]ation ( :i* is h>dly necess>y 9 ?is connection4 ,,coagulants ,,:i* ,,h ,,be5 ,,us$4 ,9 actual "w sulphate ( alum9a is practically ! only coagulant :i* has be5 employ$1 except+ ! alums1 :i* are practically its equival5t 9 action1 diff]+ only 9 /r5g?4 ,ne>ly all important exp]im5ts ^u ! coagulation ( wat] h be5 made ) sulphate ( alum9a1 & 9 ! fur!r discussion ( ?is subject only ?is coagulant w be consid]$4 ,,am\nt ,,( ,,coagulant ,,requir$ ,,to ,,remove ,,turbidity4 ,9 ! coagulation ( turbid wat]s a c]ta9 def9ite am\nt ( coagulant mu/ be employ$4 ,if less ?an ?is am\nt is us$ ei!r no precipitate w be =m$1 or x w n be =m$ 9 suffici5t bulk to effect ! desir$ results4 ,x is necess>y t ! precipitate %\ld be suffici5t1 & t x %\ld be =m$ practically all at "o "t4 ,! am\nt ( coagulant necess>y to accompli% ?is purpose is dep5d5t ^u ! turbidity ( ! raw wat]4 ,) practically cle> wat]s sulphate ( alum9a ( ! ord9>y comm]cial /r5g?1 t is to say1 ) ab\t #ag p] c5t soluble oxide ( alum9um1 us$ 9 quantities z small z #j4c or #j4d ( a gra9 p] gallon1 w produce coagulation4 ,z ! turbidity increases l>g] am\nts mu/ be employ$4 ,a special /udy 0 made ( ?is po9t 9 connection ) ! ,pittsburg exp]im5ts4#cg ,z an av]age ( ^! results x 0 f\nd t two gra9s p] gallon ( sulphate ( alum9a 7 requir$ to prop]ly coagulate wat]s hav+ turbidities ( #a4jj1 s t !y c\ld be filt]$ by ! ,jewell filt]1 & #b4ge gra9s 7 requir$ = ! ,w>r5 filt]4 ,illu/ration3 ,,fig4 #bj4--;,,am\nt ,,( ,,coagulant ,,requir$ ,,to ,,remove ,,turbidity4 ,aside f ! am\nt requir$ to produce a precipitate 9 ! cle>e/ wat]s1 ! am\nt ( coagulant requir$ 0 proportional to ! turbidity4 ,z an av]age = ! two filt]s ! requir$ quantity 0 approximately #j4cj ( a gra91 & 9 addition #j4jb ( a gra9 = ea* #j4ja ( turbidity4 ,?us a wat] hav+ a turbidity ( #j4bj requires #j4gj ( a gra9 p] gallon2 a wat] hav+ a turbidity ( #j4ej requires #a4cj gra9s2 ( #a4jj1 #b4cj gra9s2 ( #b4jj1 #d4cj gra9s1 etc4 ,^! are av]age m9imum results4 ,occasionally cle> efflu5ts 7 produc$ ) small] quantities ( coagulant1 :ile at o!r times l>g] quantities 7 necess>y = satisfactory results4 ,! am\nt ( coagulant requir$ = cl>ification at ,c9c9nati has be5 /at$ by ,mr4 ,full] 9 8 report4 ,a numb] ( 8 results are br\ght toge!r 9 ! foll[+ table1 to :i* has also be5 add$ a column %[+ approximately ! correspond+ results at ,pittsburg4 ,,e/imat$ ,,av]age ,,am\nts ,,( ,,requir$ ,,*emical ,,= ,,diff]5t ,,grades ,,( ,,wat]4 ---------------------------------------- --------------- ,*emical ,requir$1 ,gra9s p] ,gallon4 ---------------------------------------- -- ,susp5d$ ,raw ,subsid$ ,subsid$ ,m9imum = ,matt]1 ,wat] = ,wat] = ,wat] = ,raw ,wat] ,p>ts 9 ,s& ,s& ,me*anical = #ajj1jjj4 ,filt]s4 ,filt]s4 ,filt]s4 ,me*anical ,c9c9nati,c9c9nati,c9c9nati ,filt]s4 ,report1 ,report1 ,report1 ,page #bij4 ,page #bij4 ,page #cda4 ,pittsburg4 ---------------------------------------- ------------ #a4j #j #j #j4ge #j4dj #b4e #j #j #a4be #j4ej #e4j #j #j #a4ej #j4gj #g4e #j #a4cj #a4ie #j4ij #aj4j #a4ej #a4fj #b4bj #a4jj #ab4e #a4fj #a4hj #b4de #a4ae #ae4j #a4gj #b4jj #b4fe #a4cj #ag4e #a4hj #b4aj #b4he #a4dj #bj4j #a4ie #b4bj #c4jj #a4fj #cj4j #b4be #b4de #c4hj #b4jj #dj4j #b4ej #b4ge #d4dj #b4ej #ej4j #b4hj #fj4j #c4je #ge4j #c4dj #ajj4j #d4jj #abj4j #d4ge ---------------------------------------- ------------ ,mr4 ,full]'s results seem to %[ t a great] am\nt ( coagulant is requir$ = ! prep>ation ( wat] = me*anical filt]s ?an is necess>y 9 connection ) s& filt]s4 ,! results ) s& filt]s indicate t settl$ wat]s & raw wat]s conta9+ equal am\nts ( susp5d$ matt]s are ab\t equally difficult to treat4 ,! results at ,pittsburg indicate t ! raw wat]s requir$ mu* small] quantities ( coagulant = giv5 am\nts ( susp5d$ matt]s ?an 0 ! case ) subsid$ wat]s at ,c9c9nati1 ! results agree+ m closely ) ! am\nts requir$ to prep>e raw wat] = s& filt]s at ,c9c9nati4 ,,am\nt ,,( ,,coagulant ,,requir$ ,,to ,,remove ,,color4 ,! in=mation ^u ?is po9t is1 un=tunately1 v inadequate4 ,9 "s exp]im5ts made by ,mr4 ,e4 ,b4 ,we/on at ,provid5ce 9 #ahic ) a me*anical filt]1#ch ) quantities ( sulphate ( alum9a av]ag+ #j4f or #j4g ( a gra9 p] gallon1 ! removal ( color 0 usually f #gj to #ij p] c5t4 ,! /&>d us$ = ! measurem5t ( color is n /at$1 & !re is no /atem5t ( ! basis ( ! scale1 consequ5tly no means ( det]m9+ ! absolute color ( ! raw wat] ^u /&>ds commonly us$4 ,at ,we/]ly1 ,r4 ,i41 ) a ,new ,york filt]1 ! actual quantity ( pota% alum employ$ f ,oct4 #aj1 #ahif1 to ,m>* #a1 #ahig1 0 #a4id gra9s p] gallon1 ! am\nt be+ regulat$ to z l[ a figure z x 0 possible to use to secure satisfactory decolorization4 ,!re is no record ( ! color ( ! raw wat]4 ,a v r\gh e/imate w\ld place x at #j4ej ^u ! plat9um scale4 ,! *emical employ$ 9 ?is case 0 alum1 & two ?irds z l>ge a quantity ( sulphate ( alum9a w\ld probably h done correspond+ "w1 _h suitable app>atus = apply+ x be5 at h&4 ,at ,sup]ior1 ,wiscons91 ! wat] 9 ! bay com+ f ! ,/4 ,l\is ,riv]1 hav+ a color ( #b4dj plat9um scale1 0 treat$ exp]im5tally ) quantities ( sulphate ( alum9a up to #d gra9s p] gallon1 by ,mr4 ,r4 ,s4 ,we/on 9 ,janu>y1 #ahii1 b ev5 ?is quantity ( coagulant utt]ly fail$ to coagulate & decolorize x4 ,at ,gre5wi*1 ,conn41 dur+ #ahih ! av]age am\nt ( sulphate ( alum9a employ$1 z comput$ f quantities /at$ 9 ! annual report ( ! ,connecticut ,/ate ,bo>d ( ,heal? = #ahih1 0 ab\t #j4dd ( a gra9 p] gallon1 & ?is quantity suffic$ to r$uce ! color ( ! raw wat] f #j4dj to #j4cj1 plat9um /&>d4 ,?is r$uction is v slight1 & x is obvi\s t ?is quantity ( coagulant 0 n en\gh = decolorization4 ,"s exp]im5ts be>+ on color removal 7 made at ,ea/ ,provid5ce1 ,r4 ,i41 by ,mr4 ,e4 ,b4 ,we/on1 & are describ$ 9 ! ,proce$+s ( ! ,am]ican ,society ( ,civil ,eng9e]s = ,septemb]1 #ahii4 ,9 ?is case ! color is report$ to h be5 r$uc$ f #j4eh to #j4aj plat9um /&>d by ! use ( "o gra9 ( sulphate ( alum9a1 conta9+ #bb p] c5t ( effective alum9a1 equival5t to ab\t #a4cj gra9s ( ! ord9>y article p] gallon4 ,! v>i\s exp]im5ts seem to indicate t a removal f #hj to #ij p] c5t ( ! color c be effect$ by ! use ( a quantity ( sulphate ( alum9a equal to r m ?an two gra9s p] gallon = wat]s hav+ colors ( #a4jj1 plat9um /&>d1 & proportionate quantities = m & less deeply color$ wat]s4 ,) mu* less sulphate ( alum9a decolorization is n effect$1 & ev5 l>g] quantities d n remove all ( ! color4 ,! data are mu* less complete ?an c\ld be desir$1 & x is to be hop$ t exp]im5ts w be und]tak5 to ?r[ m light ^u ?is important subject4 ,,successive ,,application ,,( ,,coagulant4 ,mr4 ,full]1 9 8 exp]im5ts at ,l\isville1 has asc]ta9$ t :5 sulphate ( alum9a is add$ to extremely muddy wat] ! s$im5t absorbs "s ( ! *emical be=e x has "t to decompose1 & c>ries x to ! bottom1 & s f> z ?is is ! case1 no b5efit is d]iv$ f t "p ( ! coagulant :i* is absorb$4 ,9 o!r words1 x is necess>y to add m coagulant ?an w\ld o!rwise be necess>y because ( ?is action4 ,! data %[$ t diff]5t k9ds ( susp5d$ matt]s took up v diff]5t am\nts ( coagulant 9 ?is way4 ,) only mod]ately turbid wat]s ! loss ( *emical f ?is s\rce is unimportant4 ,h>dly any trace ( x 0 f\nd at ,pittsburg ) ! ,allegh5y ,riv] wat]4 ,at ,l\isville1 h[ev]1 x 0 an important factor1 z %[n by ,mr4 ,full]'s results4 ,to avoid ?is loss ( *emical ,mr4 ,full] has sugge/$ ! removal ( ! great] "p ( ! susp5d$ matt]s by s$im5tation1 )\t *emicals1 or ) ! aid ( a small quantity ( *emical1 foll[$ by ! application ( ! f9al coagulant prior to filtration4 ,) ! wor/ wat]s enc\nt]$ at ,l\isville ! sav+ 9 coagulant to be effect$ 9 ?is way is v great4 ,mr4 ,full] /ates 9 8,wat] ,purification at ,l\isville10 p4 #dag3 8,! practical conclusions to be drawn f ?is exp]i5ce are t ) prelim9>y coagulation1 foll[$ by subsid5ce = a p]iod ( ab\t ?ree h\rs1 ! application ( coagulants may be divid$ to advantage1 & a consid]able portion ( ! susp5d$ matt] kept (f ! filt]1 :5 ! total am\nt ( requir$ coagulant ranges f #b to #b4e gra9s or m ( ord9>y sulphate ( alum9a p] gallon4 ,9 ! case ( a wat] requir+ m ?an ?is am\nt ( coagulat+ treatm5t1 a prop] division ( ! application w\ld increase ! sav+ ( coagulants & w\ld dim9i% ! frequ5cy ( wa%+ ! filt]40 ,9 8 f9al summ>y & conclusions1 page #dda1 ,mr4 ,full] e/imates ! am\nt ( sulphate ( alum9a requir$ = ! cl>ification ( ! ,ohio ,riv] at ,l\isville at #c4jj gra9s p] gallon ( wat] filt]$ if all appli$ at "o po9t1 or at #a4ge gra9s by tak+ advantage ( subsid5ce to its economical limit prior to ! f9al coagulation4 ,! sav+ to be effect$ 9 ?is way is suffici5t to ju/ify ! works necess>y to all[ x to be c>ri$ out4 ,) less turbid wat]s1 or wat]s highly turbid = only %ort int]vals1 ! advantages ( d\ble coagulation w\ld be less app>5t4 ,,! ,,am\nt ,,( ,,coagulant ,,:i* ,,v>i\s ,,wat]s ,,w ,,receive4 ,! am\nt ( coagulant :i* c be safely us$ is dep5d5t ^u ! alkal9ity ( ! raw wat]4 ,:5 sulphate ( alum9a is add$ to wat] x is decompos$1 z expla9$ above1 ) ! =mation ( alum9a1 :i* is alone useful 9 ! "w ( purification1 & sulphuric acid1 :i* comb9es ) ! calcium c>bonate or lime pres5t 9 ! wat]4 ,!re %\ld always be an excess ( alkal9ity or lime 9 ! raw wat]4 ,if = any reason !re is n1 !re is no?+ to comb9e ) ! lib]at$ sulphuric acid1 & ! decomposition ( ! coagulant is n complete1 & a portion ( x goes undecompos$ into ! efflu5t4 ,! efflu5t !n has an acid reaction1 & is unfit = dome/ic supply4 ,:5 di/ribut$ ?r\gh iron pipes1 x attacks ! iron1 ru/+ ! pipes1 & giv+ rise to all ! disagreeable consequ5ces ( an iron conta9+ wat]4 ,! am\nt ( lime 9 a wat] available to comb9e ) ! sulphuric acid c be det]m9$ by a v simple *emical op]ation1 namely1 by titration ) /&>d acid ) a suitable indicator4 ,! am\nt ( coagulant correspond+ to a giv5 quantity ( lime c be readily & accurately calculat$1 b x is n reg>d$ safe to use z mu* sulphate ( alum9a z corresponds to ! lime4 ,! quantity ( coagulant us$ is n susceptible to exact control1 b fluctuates some:at1 & if ! exact !oretical quantity %\ld be employ$ dur+ #bd h\rs1 !re w\ld surely be an excess dur+ "s portion ( t "t f :i* bad results w\ld be exp]i5c$4 ,x is !re=e consid]$ only prud5t to use ?ree qu>t]s z mu* sulphate ( alum9a z corresponds to ! lime 9 ! wat]4 ,) sulphate ( alum9a conta9+ #ag p] c5t ( soluble alum9um oxide & ! correspond+ am\nt ( sulphuric acid1 ! am\nt :i* c be appli$ to a wat] 9 gra9s p] gallon is slightly less ?an ! alkal9ity express$ 9 t]ms ( p>ts 9 #ajj1jjj ( calcium c>bonate4 ,_m wat]s conta9 suffici5t lime to comb9e ) ! acid ( all ! coagulant :i* is necess>y = _! coagulation4 ,o!rs w n1 & x ?us becomes an important matt] to det]m9e :e!r a giv5 wat] is capable ( decompos+ suffici5t coagulant = its treatm5t4 ,x is usually ! flood-fl[s ( riv]s :i* control 9 ?is respect4 ,! wat] at su* times requires mu* l>g] quantities ( coagulant = its cl>ification1 & x also usually conta9s mu* less lime ?an ! l[-wat] fl[s4 ,! reason = ?is is obvi\sly t ! wat] ( ! flood-fl[s is l>gely ra9-wat] :i* has come ov] ! surface )\t com+ into v intimate contact ) ! soil1 & consequ5tly )\t hav+ tak5 f x mu* lime1 :ile ! l[-wat] fl[s conta9 a consid]able proportion ( wat] :i* has p]colat$ ?r\gh ! soil & has ?us become *>g$ ) lime4 ,9 "s p>ts ( ! c\ntry1 z1 = in/ance1 9 ,new ,engl&1 ! soil & und]ly+ rock are almo/ entirely free f lime1 & riv]s f su* wat]%$s are capable ( receiv+ only v small quantities ( coagulant )\t injuri\s results4 ,! defici5cy ( alkal9ity 9 raw wat] c be correct$ by ! addition to x ( lime or ( soda-a%4 ,lime has be5 us$ = ?is purpose 9 _m cases4 ,:5 us$ only 9 mod]ate am\nts x h>d5s ! wat]1 & is ?us s]i\sly objectionable4 ,! use ( s l>ge a quantity z w\ld precipitate out1 z 9 ,cl>k's process1 has n be5 employ$ 9 practice4 ,if x %\ld be attempt$1 ! am\nt ( lime w\ld require to be v accurately controll$1 & ! efflu5t w\ld h to be treat$ ) c>bonic acid to make x suitable = supply4 ,wat]s s h>d z to require ! use ( ! ,cl>k process almo/ always h suffici5t alkal9ity1 & d n require to be treat$ ) lime 9 connection ) ! use ( sulphate ( alum9a4 ,! use ( soda-a% is free f ! objections to ! use ( lime1 b is m exp5sive1 & w\ld require to be us$ ) caution4 ,its use has (t5 be5 sugge/$1 b ,i d n "k t x has ev] be5 employ$ 9 practice4 ,9 small works ! use ( a filt]+ mat]ial conta9+ m>ble-du/1 or o!r calc>e\s matt]1 w\ld seem to h "s advantages 9 case ( defici5cy ( alkal9ity1 al?\gh x w\ld h>d5 ! wat] s treat$4 ,! alkal9ities ( a numb] ( wat]s comput$ z p>ts 9 #ajj1jjj ( calcium c>bonate 7approximately equal to ! safe doses ( sulphate to alum9a 9 gra9s p] gallon7 are z foll[s3 ---------------------------------------- --------------------- ,maximum4,m9imum4,av]age4 ---------------------------------------- --------------------- ,bo/on wat]1 #ahih #b4hg #j4cc #a4jh ,cone/oga ,creek1 ,lanca/]1 ,p5n4 #ab4bj #c4gj #f4hj ,allegh5y ,riv]1 ,pittsburg #h4jj #a4jb #b4ij ,mahon+ ,riv] & tribut>ies1 #ahig #bj4jj #b4bj #aj4jj ,scioto ,riv] & tribut>ies1 #ahig #ce4jj #aj4jj #bj4jj ,ohio ,riv]1 ,c9c9nati1 #ahih #g4jj #b4jj #d4ej ,ohio ,riv]1 ,l\isville #aj4hg #b4ab #f4gj ,lake ,erie1 ,lora91 ,ohio #i4ej ,lake ,mi*igan1 ,*icago #aa4ej ---------------------------------------- --------------------- ,,*apt] ,x4 ,,me*anical ,,filt]s4 ,! t]m me*anical filt]s is us$ to designate a g5]al class ( filt]s diff]+ 9 _m respects q radically f ! s& filt]s previ\sly describ$4 ,!y _h _! orig9 9 ! ,unit$ ,/ates1 & consi/$ orig9ally ( iron or wood5 cyl9d]s fill$ ) s& ?r\gh :i* ! wat] 0 =c$ at rates ( "o to two hundr$ million gallons p] acre daily1 or f fifty to "o hundr$ times ! rates usually employ$ ) s& filt]s4 ,^! filt]s 7 fir/ us$ 9 pap]-mills to remove f ! l>ge volumes ( wat] requir$ ! comp>atively l>ge p>ticles1 :i* w\ld o!rwise affect ! appe>ance & texture ( ! pap]2 & 9 _! e>li] =ms !y 7 entirely inadequate to remove ! f9] p>ticles1 su* z ! bact]ia1 & ! clay p>ticles :i* con/itute ! turbidity ( riv] wat]s4 ,v>i\s improvem5ts 9 con/ruction h s9ce be5 made1 &1 9 connection ) ! use ( coagulants1 mu* m satisfactory results c n[ be obta9$ ) filt]s ( ?is class2 & _! use has be5 ext5d$ f manufactur+ op]ations to municipal supplies1 9 _m cases ) mo/ satisfactory results4 ,! in=mation ga!r$ 9 reg>d to ! conditions ess5tial to ! successful design & op]ation ( ^! filt]s 9 ! la/ few ye>s is v great1 & may be briefly review$4 ,,provid5ce ,,exp]im5ts4#ci ,! fir/ data ( importance 7 secur$ f a s]ies ( exp]im5ts conduct$ by ,mr4 ,edmund ,b4 ,we/on ( ,provid5ce1 ,r4 ,i41 9 #ahic & #ahid1 ^u ! ,pawtuxet riv] wat] us$ by t city4 ,! exp]im5tal filt] 0 #cj in*es 9 diamet]1 & _h a lay] ( s& #b feet #aj in*es deep4 ,! s& 0 wa%$ by ! use ( a rev]se curr5t1 ! s& be+ /irr$ by a revolv+ rake at ! same "t4 ,! am\nt ( coagulant employ$ 0 ab\t #j4g ( a gra9 p] gallon4 ,! raw wat] 0 practically free f turbidity1 & ! filt] 0 op]at$ to remove color & bact]ia4 ,! removal ( color1 z /at$ 9 ,mr4 ,we/on's report1 am\nt$ to f #gj to #ij p] c5t4 ,! exp]im5ts ext5d$ ov] a p]iod ( t5 mon?s4 ,! rate ( filtration employ$ 0 ab\t #abh million gallons p] acre daily4 ,! bact]ial results ( ! fir/ six mon?s' op]ations 7 reject$ by ,mr4 ,we/on on acc\nt ( defective me?ods ( manipulation4 ,dur+ ! p]iod f ,novemb] #ag1 #ahic1 to ,janu>y #cj1 #ahid1 ! av]age bact]ial effici5cy ( filtration 0 ab\t #ie p] c5t1 & ! manipulation 0 consid]$ to be 9 e respect satisfactory4 ,! effici5cy 0 occasionally bel[ #ij p] c5t1 b = f\r select$ weeks 0 z high z #ih4f p] c5t4 ,! av]age am\nt ( sulphate ( alum9a us$1 z calculat$ f ,mr4 ,we/on's tables1 0 two ?irds ( a gra9 p] gallon4 ,! highe/ effici5cy foll[$ ! application ( a solution ( cau/ic soda to ! filt]+ mat]ial4 ,! fir/ day foll[+ ?is treatm5t ! bact]ial effici5cy 0 above #ii p] c5t4 ,aft]w>ds x decreas$ until ,janu>y #cj1 :5 ! exp]im5ts 7 /opp$4 ,! high bact]ial effici5cy foll[+ ! use ( cau/ic soda 0 ( su* %ort duration z to sugge/ v grave d\bts z to its practical value4 ,x is extremely un=tunate t ! exp]im5ts /opp$ only a week aft] ?is exp]im5t1 & ! results 7 nev] repeat$4 ,i consid] t ! av]age bact]ial effici5cy ( ab\t #ie p] c5t obta9$ = ! p]iod ( ,octob] #ag to ,janu>y #cj1 :5 ! manipulation 0 consid]$ to be 9 e way satisfactory1 m ne>ly repres5ts :at c be obta9$ "u ^! conditions ?an ! results = c]ta9 p]iods1 p>ticul>ly aft] ! use ( ! cau/ic soda4 ,,l\isville ,,exp]im5ts4#dj ,^! exp]im5ts 7 inaugurat$ by ! ,l\isville ,wat] ,company 9 connection ) ! manufactur]s ( c]ta9 pat5t$ filt]s4 ,mr4 ,*>les ,h]many1 ,*ief ,eng9e] ( ! ,company1 _h g5]al *>ge ( ! exp]im5ts4 ,mr4 ,george ,w4 ,full] 0 ,*ief ,*emi/ & ,bact]iologi/ & _h direct *>ge ( ! "w & has made a mo/ elaborate report ^u ! same4 ,9 ^! exam9ations _m devices 7 inve/igat$2 b ! two :i* p>ticul>ly des]ve our att5tion are ! filt]s kn[n z ! ,w>r5 ,filt] & ! ,jewell ,filt]4 ,^! filt]s 7 op]at$ = two p]iods1 namely1 f ,octob] #ah1 #ahie1 to ,july #cj1 #ahif1 & f ,april #e to ,july #bd1 #ahig4 ,! inve/igations 7 direct$ t[>d ! cl>ification ( ! riv] wat] f ! mud1 & to ! removal ( bact]ia4 ,! wat] 0 sub/antially free f color4 ,! "* ( ! wat] at ?is po9t 0 su* t 9 its be/ condition at lea/ ?ree f\r?s ( a gra9 ( sulphate ( alum9a 7 necess>y = its coagulation1 & ) ?is & ) l>g] quantities ( coagulant fair bact]ial purification 0 ne>ly always obta9$4 ,! problem /udi$ !re=e 0 pr9cipally t ( cl>ification f mud4 ,! av]age effici5cies1 z %[n by ! total av]ages1 7page #bdh17 7 z foll[s3 ,w>r5 filt]1 bact]ial effici5cy1 #if4g p] c5t2 ,jewell filt]1 #if4j p] c5t4 ,,lora9 ,,te/s4#da ,^! te/s 7 made by ! au?or ( a set ( ,jewell filt]s at ,lora91 ,ohio4 ,! filt]s 7 six 9 numb]1 ea* #ag feet 9 diamet]1 hav+ an effective filt]+ area ( #bbf squ>e feet ea*1 or #acef squ>e feet 9 all4 ,! con/ruction ( ! filt]s 0 9 all respects simil> to ! ,jewell filt] us$ at ,l\isville4 ,! raw wat] 0 f ,lake ,erie1 & dur+ ! exam9ation 0 always comp>atively cle>1 b conta9$ consid]able numb]s ( bact]ia4 ,! problem 0 ?us entirely "o ( bact]ial effici5cy4 ,! "q ( cl>ification h>dly pres5t$ itself4 ,al?\gh ! wat] became turbid at times x did n approa* 9 mudd9ess ! condition ( ! ,ohio ,riv] wat]1 & an am\nt ( coagulant suffici5t = a tol]able bact]ial effici5cy 9 all cases 0 m ?an suffici5t = cl>ification4 ,a summ>y ( ! results obta9$ is z foll[s3 ---------------------------------------- ----------------------- ,av]age ,rate ,sulphate ( ,bact]ial ,week ,end+( ,filtration1 ,alum9a1 ,bact]ia,bact]ia ,effici5cy #f3jj ,p4,m4 ,gallons p] ,gra9s p] 9 ,lake 9 p] c5t4 ,sq4 ,ft4 ,m94 ,gallon4 ,wat]4 ,efflu5t4 ---------------------------------------- ----------------------- ,june #ai #a4jf #b4eh #adda #af #ih4i #bf #a4aj #b4ej #che #f #ih4d ,july #c #a4aa #b4bg #cfg #i #ig4e #aj #a4bh #a4jg #aed #ad #ij4i #ag #a4ad #j4id #ahi #bf #hf4c ---------------------------------------- ------------ ,av]age #a4ad #a4hc #ejg #ad #if4d ---------------------------------------- ----------------------- ,! av]age bact]ial effici5cy 0 #if4d p] c5t ) #a4hc gra9s ( sulphate ( alum9a p] gallon4 ,,pittsburg ,,exp]im5ts4#db ,! ,pittsburg exp]im5ts 7 inaugurat$ by ! ,pittsburg ,filtration ,commission4 ,! op]ation ( ! filt]s ext5d$ f ,janu>y to ,augu/1 #ahih4 ,a ,jewell & a ,w>r5 filt] 7 us$ simil> 9 design to ^? us$ at ,l\isville4 ,! raw wat] conta9$ l>ge numb]s ( bact]ia1 & 0 also (t5 v turbid1 al?\gh less turbid ?an at ,l\isville4 ,at times m coagulant 0 necess>y = cl>ification ?an 0 requir$ = bact]ial effici5cy2 :ile z a rule m 0 requir$ = satisfactory bact]ial purification ?an 0 necess>y = cl>ification4 ,! opportunities 7 !re=e favorable = ! /udy ( bo? ( ^! conditions4 ,! am\nt ( coagulant necess>y = cl>ification has be5 m5tion$ 9 connection ) coagulation4 ,! results secur$ ^u ! relation ( ! quantity ( coagulant to ! numb] ( bact]ia 9 ! efflu5t 7 m complete ?an any o!r exp]im5ts available1 & are !re=e "h reproduc$ f ! ,pittsburg report ne>ly 9 full4 ,x 0 f\nd t ! am\nt ( sulphate ( alum9a employ$ 0 m important ?an any o!r factor 9 det]m9+ ! bact]ial effici5cy1 & special exp]im5ts 7 made to e/abli% ! effect ( m & ( less coagulant ?an us$ 9 ! ord9>y "w4 ,^! exp]im5ts 7 made ^u ! ,w>r5 filt] dur+ ,may1 & ) ! ,jewell filt] dur+ ,june4 ,! mon?ly av]ages = ^! mon?s are ?us abnormal & are n to be consid]$4 ,! rema9+ six mon?s = ea* filt] may be tak5 z normal & z repres5t+ approximately ! "w ( ^! filt]s "u ord9>y c>eful work+ conditions4 ,dur+ ! six mon?s :5 ! ,w>r5 filt] 0 9 normal ord] ! raw wat] conta9$ #aa1eca bact]ia & ! efflu5t #bja1 ! av]age bact]ial effici5cy be+ #ih4bf p] c5t4 ,! bact]ial effici5cy 0 v con/ant1 rang+ only1 by mon?s1 f #ig4dh to #ih4if p] c5t4 ,dur+ ! same p]iod a s& filt] receiv+ ! same wat] yield$ an efflu5t hav+ an av]age ( #aje bact]ia p] cubic c5timet]4 ,! ,jewell filt]1 = ! six mon?s 9 :i* x 0 9 normal ord]1 receiv$ raw wat] conta9+ an av]age ( #aa1dha bact]ia & yield$ an efflu5t conta9+ an av]age ( #bic1 ! bact]ial effici5cy be+ #ig4de p] c5t1 & rang+1 9 diff]5t mon?s1 f #ic4bc to #ih4fa p] c5t4 ,,wa/+ ,,efflu5t ,,aft] ,,wa%+ ,,filt]s4 ,aft] wa%+ a me*anical filt] ! efflu5t = ! fir/ few m9utes is (t5 inf]ior 9 quality to t obta9$ at o!r times1 & if samples are tak5 at ^! times & av]ag$ ) o!r samples tak5 dur+ ! run1 an app>5t effici5cy may be obta9$ inf]ior to ! true effici5cy4 ,to gu>d aga9/ ?is s\rce ( error1 :5ev] samples h be5 tak5 at su* times1 ! av]age "w = ! day has be5 tak51 n z ! num]ical av]age ( ! results1 b ea* sample has be5 giv5 weight 9 proportion to ! am\nt ( "t :i* x c\ld be tak5 z repres5t+2 s t ! results repres5t z ne>ly z possible ! av]age numb] ( bact]ia 9 ! efflu5t = ! :ole run4 ,z a matt] ( fact1 h[ev]1 comp>atively few samples 7 tak5 dur+ ^! p]iods ( r$uc$ effici5cy1 & ?us mo/ ( ! results repres5t ! normal effici5cy exclusive ( ?is p]iod4 ,a /udy has be5 made1 h[ev]1 ( ! results ( exam9ations ( samples tak5 directly aft] wa%+1 some:at 9 detail4 ,! foll[+ is a tabul> /atem5t ( ! av]age results obta9$ f ea* filt] by mon?s1 includ+ only ! results obta9$ on ^? days :5 samples 7 tak5 )9 tw5ty m9utes aft] wa%+1 ! results ( o!r days be+ exclud$4 ,,av]age ,,numb] ,,( ,,bact]ia ,,9 ,,efflu5t4 ---------------------------------------- ------------------------- ,%[n by ,)9 ,t5 #aa to #bj ,m ?an ,record ,m9utes aft],m9utes aft] ,tw5ty ,%eets4 ,wa%+4 ,wa%+4 ,m9utes aft] ,wa%+4 ---------------------------------------- ------------------------- ,,w>r5 ,,filt]4 ,febru>y #aae #aah #aad ,m>* #caf #ej #eae #cja ,april #gi #dag #bjg #ge ,may 7,special exp]im5ts1 omitt$47 ,june #aig #dic #bgb #agj ,july #cjj #edf #bjg ,augu/ #agd #cef #fja #bbc ,,jewell ,,filt]4 ,febru>y #bdec #bdbe #bjii ,m>* #dee #feg #ieh #ced ,april #ii #ffe #dfb #afe ,may #add #iih #cdf #abg ,june 7,special exp]im5ts1 omitt$47 ,july #bgi #accj #bgb #bgd ,augu/ #cdd #fab #cbc #cgf ---------------------------------------- ------------------------- ,! "t ( inf]ior "w v r>ely exce$$ tw5ty m9utes4 ,x w be se5 f ! tables t ! results z %[n by ! record %eets are nev] v mu* high]1 & are occasionally l[] ?an ! results ( samples tak5 on correspond+ days m ?an tw5ty m9utes aft] wa%+2 & ?us :ile a decrease 9 bact]ial effici5cy 0 not$ aft] wa%+1 no mat]ial increase 9 ! av]age bact]ial effici5cy ( ! me*anical filt]s w\ld h be5 obta9$ if ^! results _h be5 exclud$4 ,! results = ! :ole "t w\ld be affect$ mu* less ?an is indicat$ by ! table1 because ! table includes only results ( ^? days :5 samples 7 tak5 j aft] wa%+1 :ile ! mu* l>g] numb] ( days :5 no su* samples 7 tak5 w\ld %[ no *ange :atev]4 ,x has be5 sugge/$ t ^! inf]ior efflu5ts aft] wa%+ %\ld be wa/$4 ,su* a proc$ure w\ld mean wa/+ probably on an av]age two p] c5t ( ! wat] filt]$1 & a correspond+ increase 9 ! co/ ( filt]+4 ,mr4 ,full]#dc 9 8 ,l\isville report comes to ! conclusion t ) adequate wa%+ & coagulation x is unnecess>y to wa/e any efflu5t1 & t inf]ior results aft] wa%+ usually indicate incomplete wa%+4 ,:ile our exp]im5ts c]ta9ly indicate a r$uction 9 effici5cy aft] wa%+ s regul> & p]si/5t z to make x d\btful :e!r incomplete wa%+ c be ! cause ( x1 x may be que/ion$ :e!r or n wa/+ ! efflu5t w\ld be necess>y or desirable 9 actual op]ation4 ,at any rate ! results z giv5 9 ?is report are n mat]ially influ5c$ by ?is factor4 ,,influ5ce ,,( ,,am\nt ,,( ,,sulphate ,,( ,,alum9a ,,on ,,bact]ial ,,effici5cy ,,( ,,me*anical ,,filt]s4 ,! numb] ( bact]ia pass+ a me*anical filt] is dep5d5t pr9cipally ^u ! am\nt ( sulphate ( alum9a us$2 & by us+ a l>g] quantity ( sulphate ( alum9a ?an 0 actually us$ 9 ! exp]im5ts ! bact]ial effici5cy c\ld be consid]ably increas$4 ,to inve/igate ?is po9t1 ! results obta9$ ea* day ) ea* ( ! me*anical filt]s 7 arrang$ 9 ! ord] ( ! sulphate ( alum9a quantities us$1 & av]ag$ by classes4 ,9 ?is & ! foll[+ tables a few abnormal results 7 omitt$4#dd ,a summ>y ( ! results is z foll[s3 ,,summ>y ,,( ,,results ,,) ,,w>r5 ,,me*anical ,,filt]1 ,,arrang$ ,,accord+ ,,to ,,sulphate ,,( ,,alum9a ,,quantities4 ---------------------------------------- ------------------------------- ,numb] ,bact]ia4 ,sulphate ( ( ,days ,turbidity4------------------- ,p] c5t ,p] c5t ,alum9a ,repres5t$4 ,raw ,wat]4,efflu5t4rema9+4remov$4us$ ,gra9s p] ,gallon4 ---------------------------------------- ------------------------------ #g #j4je #d1ggc #agac #ce4hi #fd4aa #j4jj #b #j4jh #b1ghe #hej #cj4eb #fi4dh #j4ab #d #j4aj #e1aji #gbf #ad4ba #he4gi #j4bf #b #j4bj #h1gac #bad #b4de #ig4ee #j4cf #h #j4jf #c1bbd #aab #c4dg #if4ec #j4dd #ai #j4jf #c1dhh #abc #c4ec #if4dg #j4ee #aa #j4jf #e1fgc #aed #b4ga #ig4bi #j4fd #aj #j4aj #f1ajj #aab #a4hd #ih4af #j4gd #h #j4ji #h1fdg #adh #a4ga #ih4bi #j4he #e #j4af #e1fde #adb #b4eb #ig4dh #j4ic #ac #j4ab #aj1cig #bjj #a4ib #ih4jh #a4jg #aj #j4jh #ab1ggh #aba #j4ie #ii4je #a4ac #ac #j4ad #ac1cig #afd #a4bb #ih4gh #a4be #ai #j4ac #aj1dfb #afj #a4ec #ih4dg #a4cd #aj #j4ab #ab1hea #ajg #j4hc #ii4ag #a4df #d #j4bg #af1jae #gg #j4dh #ii4eb #a4eg #g #j4ec #ab1bfb #aia #a4ah #ih4hb #a4fd #d #j4eh #bf1iej #cdg #a4bi #ih4ga #a4gd #e #j4bi #ad1egj #hf #j4ei #ii4da #a4hd #c #j4bc #ac1hcc #aec #a4aa #ih4hi #a4ib #ai #j4dj #ah1bbb #ib #j4ej #ii4ej #b4dh #e #j4de #bi1cjj #aaai #c4hb #if4ah #c4cg #e #a4jf #cc1jcj #ece #a4fb #ih4ch #h4jf ---------------------------------------- ------------------------------ ,,summ>y ,,( ,,results ,,) ,,jewell ,,me*anical ,,filt]1 ,,arrang$ ,,accord+ ,,to ,,sulphate ,,( ,,alum9a ,,quantities4 ---------------------------------------- ------------------------------ ,numb] ,bact]ia4 ,sulphate ( ( ,days ,turbidity4------------------- ,p] c5t ,p] c5t ,alum9a ,repres5t$4 ,raw ,wat]4,efflu5t4rema9+4remov$4us$ ,gra9s p] ,gallon4 ---------------------------------------- ------------------------------ #f #j4jc #ad1jcg #fbag #dd4bi #ee4ga #j4jj #e #j4jg #d1bfg #fhj #ae4ic #hd4jg #j4bd #ad #j4jf #b1fac #agj #f4ej #ic4ej #j4ce #aj #j4jf #b1ddf #aac #d4fb #ie4ch #j4dd #i #j4aa #g1cjc #bcd #c4bj #if4hj #j4ee #bj #j4ji #f1igi #bbj #c4ae #if4he #j4fe #i #j4jh #e1aia #acj #b4ej #ig4ej #j4ge #af #j4ab #h1ejd #bdb #b4hd #ig4af #j4hc #bb #j4af #h1ejf #ii #a4af #ih4hd #j4if #ab #j4aa #aa1iih #bdf #b4je #ig4ie #a4je #ad #j4ah #ah1ihb #dbc #b4bc #ig4gg #a4af #e #j4ad #ac1iha #bbd #a4fj #ih4dj #a4bc #i #j4bg #ai1hjf #cbe #a4fd #ih4cf #a4cd #ad #j4bg #af1edi #cbd #a4if #ih4jd #a4de #i #j4bi #ab1aid #if #j4gi #ii4ba #a4ed #f #j4be #ac1dhc #ea #j4ch #ii4fb #a4fe #g #j4ec #bd1bdc #bbj #j4ia #ii4ji #a4gb #c #j4ij #bj1iec #fjb #b4hh #ig4ab #a4ij #e #j4dc #be1ieh #cjg #a4ai #ih4ha #b4ai #d #j4hd #ba1jag #bbh #a4ji #ih4ia #c4ga ---------------------------------------- ------------------------------ ,^! results are %[n graphically by ,fig4 #ba4 ,illu/ration3 ,,fig4 #ba4--;,,bact]ial ,,effici5cies ,,( ,,me*anical ,,filt]s4 ,,influ5ce ,,( ,,degree ,,( ,,turbidity ,,^u ,,bact]ial ,,effici5cy ,,( ,,me*anical ,,filt]s4 ,x w be notic$ by ref]r+ to ! tables t z ! sulphate ( alum9a quantities increas$ ! turbidities increas$ & ! numb]s ( bact]ia increas$1 z well z ! bact]ial effici5cies4 ,t is to say1 ) ! less turbid wat]s1 small sulphate ( alum9a quantities h be5 us$1 ! numb]s ( bact]ia 9 ! raw wat] h be5 l[1 & ! bact]ial effici5cies h also be5 l[4 ,) turbid wat]s mu* l>g] quantities ( sulphate ( alum9a h be5 us$1 ! raw wat] has conta9$ m bact]ia1 & ! bact]ial effici5cies h be5 high]4 ,x may be !n t ! increas$ effici5cies ) increas$ quantities ( sulphate ( alum9a are n due alone to ! increas$ sulphate ( alum9a1 b 9 "p also to o!r conditions4 ,?us x may be easi] to remove a l>ge p]c5tage ( bact]ia f a wat] conta9+ _m ?an f a wat] conta9+ only a few4 ,to inve/igate ?is matt] & elim9ate ! influ5ce ( turbidity & numb]s ( bact]ia 9 ! raw wat]1 ! results 7 fir/ classifi$ ) ref]5ce to turbidity4 ,! results ) wat]s hav+ turbidities ( #j4aj or less1 & call$ = conv5i5ce turbid wat]s1 are arrang$ by alum quantities z be=e4 ,aft]w>ds ! results obta9$ ) turbidities f #j4aa to #j4ej1 & call$ = conv5i5ce muddy wat]s1 are gr\p$2 & f9ally ! results ) turbid wat] hav+ turbidities ( #j4ea & ov]1 & call$ = conv5i5ce ?ick wat]s4 ,! results ?us arrang$ are z foll[s3 ,,summ>y ,,( ,,results ,,) ,,w>r5 ,,me*anical ,,filt]1 ,,arrang$ ,,accord+ ,,to ,,turbidities ,,& ,,sulphate ,,( ,,alum9a ,,quantities4 ---------------------------------------- ------------------------------- ,sulphate ( ,numb] ,bact]ia4 ,p] c5t ,p] c5t ,alum9a ( ,days ,turbidity4-------------------rema9+4rem ov$4us$ ,gra9s ,repres5t$4 ,raw ,wat]4,efflu5t4 p] ,gallon4 ---------------------------------------- ------------------------------ #g #j4je #d1ggc #agac #ce4hi #fd4aa #j4jj #b #j4jg #b1ghe #hej #cj4eb #fi4dh #j4ab #ab #j4jf #c1bji #bbd #g4jj #ic4jj #j4db #ca #j4jf #d1bch #aai #b4ha #ig4ai #j4fj #i #j4jf #g1iec #acj #a4fd #ih4cf #j4hd #af #j4jd #aa1bfe #acg #a4bb #ih4gh #a4aa #bi #j4jf #aa1ejj #aeh #a4cg #ih4fc #a4eh #e #j4ag #h1ghc #daf #d4gc #ie4bg #j4cf #aj #j4af #f1ece #afe #b4ed #ig4df #j4he #ac #j4ai #ac1bec #ahf #a4dj #ih4fj #a4ac #ae #j4bb #aj1idd #ic #j4he #ii4ae #a4cf #ac #j4bi #ad1jhi #aab #j4hj #ii4bj #a4gc #aj #j4ce #ah1jhh #ajb #j4eg #ii4dc #b4ch #e #j4bi #be1ehj #edj #b4aa #ig4hi #d4cj #f #j4hg #be1dcc #cfi #a4de #ih4ee #a4gd #f #j4gc #bf1eff #gi #j4cj #ii4gj #b4fd #d #a4ce #db1jcg #achh #c4cj #if4gj #h4af ---------------------------------------- ------------------------------ ,,summ>y ,,( ,,results ,,) ,,jewell ,,me*anical ,,filt]1 ,,arrang$ ,,accord+ ,,to ,,turbidities ,,& ,,sulphate ,,( ,,alum9a ,,quantities4 ---------------------------------------- ------------------------------- ,sulphate ( ,numb] ,bact]ia4 ,alum9a ( ,days ,turbidity4------------------- ,p] c5t ,p] c5tus$ ,gra9s ,repres5t$4 ,raw ,wat]4,efflu5t4rema9+4remov$4p] ,gallon4 ---------------------------------------- ------------------------------ #f #j4jc #ad1jcg #fbag #dd4bi #ee4ga #j4jj #c #j4jg #e1agj #iia #ai4ae #hj4he #j4ba #be #j4je #b1djc #adc #e4ie #id4je #j4ch #bj #j4jf #f1eca #ahe #b4hd #ig4af #j4fd #bg #j4jf #e1haa #abb #b4aj #ig4ij #j4hh #ad #j4jf #ad1igh #dab #b4ge #ig4be #a4aa #aj #j4jf #ae1ghg #cij #b4dg #ig4ec #a4cg #aj #j4je #aj1hdg #dg #j4dc #ii4eg #b4ag #ad #j4af #g1ebe #bef #c4dj #if4fj #j4fj #ag #j4bd #aa1caj #bjh #a4hd #ih4af #j4ia #ae #j4bd #ae1dda #bfb #a4gj #ih4cj #a4ac #aj #j4bh #ag1hdb #bcb #a4cj #ih4gj #a4dc #h #j4bi #i1eef #ei #j4fb #ii4ch #a4ei #d #j4bi #bj1bab #ace #j4fg #ii4cc #b4jj #e #j4ff #bc1fhj #ccf #a4db #ih4eh #a4db #g #j4if #cj1bjj #dge #a4eg #ih4dc #a4gd #d #a4be #cg1ehg #dif #a4cb #ih4fh #b4ha ---------------------------------------- ------------------------------ ,! foll[+ table %[s ! bact]ial effici5cies ) turbid1 muddy1 & ?ick wat]s1 ) sub/antially equal quantities ( sulphate ( alum9a3 ---------------------------------------- ---------------------------- ,gra9s ( ,sulphate ( ,alum9a4,correspond+ ,bact]ial ,effici5cies4 ---------------------------------------- ------------------------ ,turbid4 ,muddy4 ,?ick4 ,turbid4 ,muddy4 ,?ick4 ---------------------------------------- ------------------------ ,,w>r5 ,,filt]4 #j4db #j4cf #ic4jj #ie4bg #j4hd #j4he #ih4cf #ig4df #a4aa #a4ac #ih4gh #ih4fj #a4eh #a4gc #a4gd #ih4fc #ii4bj #ih4ee #b4ch #b4fd #ii4dc #ii4gj #d4cj #h4af #ig4hi #if4gj ,,jewell ,,filt]4 #j4fd #j4fj #ig4af #if4fj #j4hh #j4ia #ig4ij #ih4af #a4aa #a4ac #ig4be #ih4cj #a4cg #a4dc #a4db #ig4ec #ih4gj #ih4eh #b4ag #a4ei #a4gd #ii4eg #ii4ch #ih4dc #b4jj #b4ha #ii4cc #ih4fh ---------------------------------------- ------------------------- ,x appe>s f ?is table t wat]s ( v>i\s degrees ( turbidity give sub/antially equal bact]ial effici5cies ) equal quantities ( sulphate ( alum9a1 ! results v>y+ z (t5 9 "o direction z ! o!r4 ,)9 c]ta9 limits x may ?us be said t turbidity is )\t influ5ce ^u ! bact]ial effici5cy obta9$ 9 me*anical filtration4 ,x mu/ be borne 9 m9d1 h[ev]1 t ! quantities ( sulphate ( alum9a1 ) v few exceptions1 7 suffici5t to produce full coagulation4 ,mr4 ,full] has %[n 9 8 ,l\isville report t consid]able quantities ( sulphate ( alum9a may be add$ to turbid wat]s )\t produc+ appreciable coagulation2 & !re=e if a quantity ( sulphate ( alum9a suffici5t to produce a c]ta9 bact]ial effici5cy 9 a cle> wat] %\ld be add$ to a wat] s turbid t x 0 unable to coagulate x1 sc>cely any effect w\ld be produc$4 ,! above /atem5t !re=e only applies 9 ^? cases :]e suffici5t sulphate ( alum9a is us$ to adequately coagulate ! wat]4 ,z ! numb]s ( bact]ia (t5 v>y ) ! turbidity1 ! v>iation 9 ! numb]s ( bact]ia 9 ! diff]5t classes is mu* less ?an 9 ! fir/ tables2 b to fur!r inve/igate ! "q ( :e!r ! numb]s ( bact]ia 9 ! raw wat] h an important influ5ce ^u ! bact]ial effici5cies1 ea* ( ! two l>ge/ classes 9 ! =ego+ tables 0 divid$ into two p>ts1 accord+ to ! bact]ial numb]s 9 ! raw wat]1 namely1 ! results f ! ,jewell filt] ) turbid wat]s & ) sulphate ( alum9a quantities rang+ f #j4ge to #a4jj gra9 p] gallon1 & ! results f ! ,w>r5 filt] ) turbid wat]s & ) sulphate ( alum9a quantities ( #a4be gra9s p] gallon & upw>d4 ,! results are z foll[s3 ---------------------------------------- ------------------------------- ,sulphate ,numb] ,bact]ia4 ( ,alum9a ( ,days ,turbidity4------------------- ,p] c5t ,p] c5tus$ ,gra9s ,repres5t$4 ,raw ,wat]4,efflu5t4rema9+4remov$4p] ,gallon4 ---------------------------------------- ------------------------------ ,,jewell ,,filt]4 #ad #j4je #c1ich #ha #b4jf #ig4id #j4hh #ac #j4jg #g1hbg #afg #b4ac #ig4hg #j4hg ,,w>r5 ,,filt]4 #ae #j4jf #c1ede #ei #a4ff #ih4cd #a4fg #ad #j4jf #bj1jbb #bfe #a4cb #ih4fh #a4dh ---------------------------------------- ------------------------------ ,x w be obs]v$ t ! bact]ial effici5cies are sub/antially ! same1 ) ! l[] & ) ! high] numb]s ( bact]ia 9 ! raw wat]4 ,t is to say1 o!r ?+s be+ equal1 z ! numb] ( bact]ia increase 9 ! raw wat] ! numb] ( bact]ia 9 ! efflu5t increase 9 ! same ratio4 ,a fur!r analysis ( o!r gr\ps ( results w\ld p]haps %[ v>iations 9 "o direction or ! o!r1 b on ! :ole x is believ$ t ! comp>ison is a fair "o1 & t !re is no well-m>k$ t5d5cy = bact]ial effici5cies ( me*anical filt]s to increase or decrease ) increas+ numb]s ( bact]ia4 ,,av]age ,,results ,,obta9$ ,,) ,,v>i\s ,,quantities ,,( ,,sulphate ,,( ,,alum9a4 ,z x appe>s t nei!r ! turbidity nor ! numb] ( bact]ia 9 ! raw wat] has a mat]ial influ5ce ^u ! p]c5tage bact]ial effici5cy obta9$1 we c take ! results giv5 above1 :i* include all ! results obta9$ 7except a v few abnormal ones7 = comput+ ! v>i\s effici5cies obta9$ ) v>i\s quantities ( sulphate ( alum9a4 ,^! results are graphically %[n by ,fig4 #ba1 p4 #afg1 on :i* l9es h be5 drawn indicat+ ! normal effici5cies f v>i\s quantities ( sulphate ( alum9a z d$uc$ f our exp]im5ts4 ,9 comput+ ! am\nt ( sulphate ( alum9a :i* x w\ld be necess>y to use 9 op]at+ a plant at a giv5 place to give ^! effici5cies1 ! quantities ( sulphate ( alum9a %[n by ! diagram c be tak5 z ^? :i* x w\ld be necess>y to use dur+ ^? days 9 ! ye> :5 ! raw wat] 0 cle>1 or suffici5tly cle>1 s t ! am\nts ( sulphate ( alum9a m5tion$ w\ld suffice to prop]ly coagulate x4 ,,types ,,( ,,me*anical ,,filt]s4 ,sections ( ! ,w>r5 & ,jewell filt]s us$ at ,pittsburg are pres5t$ h]e)4 ,! filt]s "h %[n are practically id5tical ) ^? us$ at ,lora9 & ,l\isville1 & ne>ly all ! exact in=mation reg>d+ me*anical filt]s relates to filt]s ( ^! types4 ,^! sections %[ cle>ly ! con/ructions us$ at ,pittsburg & ,l\isville1 b !re are "s po9ts 9 connection ) ! designs ( ^! filt]s :i* require to be consid]$ m 9 detail4 ,! simple/ idea ( a me*anical filt] is a tub1 ) s& 9 ! bottom & "s =m ( dra9age sy/em4 ,wat] is run ov] ! s&1 passes ?r\gh x1 & is collect$ by ! dra9age sy/em4 ,:5 ! s& becomes clogg$ x is wa%$ by ! use ( a rev]se curr5t ( wat]4 ,?is rev]se curr5t ( wat] is s rapid z to preclude ! use ( a dra9age sy/em consi/+ ( gravel1 tile-dra9s1 etc41 su* z are us$ 9 s& filt]s op]at$ at l[] rates1 & in/ead metallic /ra9]s 9 "s =m are us$4 ,! s& comes directly aga9/ ^! /ra9]s1 :i* are made z co>se z x is possible to h !m1 )\t all[+ ! s& to pass4 ,! rate ( wa%+ is usually f five to sev5 gallons p] squ>e foot p] m9ute4 ,9 ! ,w>r5 filt] ! op5+s 9 ! /ra9]s at ! bottom are #f to #h p] c5t ( ! total area1 & dur+ wa%+ ! wat] has an av]age velocity ( #j4bj foot p] second upw>d ?r\gh !m4 ,?is velocity is s sl[ t ! friction ( ! wat] 9 pass+ ?r\gh ! op5+s 9 ! scre5 is practically no?+4 ,a result ( ?is is t if !re is any unequal resi/ance ( ! s& to ! wat]1 ! bulk ( ! wat] goes up at ! po9ts ( lea/ resi/ance 9 ! s&4 ,illu/ration3 ,,fig4 #bb4--,,section ,,( ,,jewell ,,me*anical ,,filt] ,,us$ ,,9 ,,pittsburg ,,exp]im5ts4 ,?is t5d5cy w\ld be fatal 7 x n = ! revolv+ rake :i* loos5s & mixes ! s& & l>gely corrects x4 ,! correction1 h[ev]1 is imp]fect1 & "s p>ts ( ! filt] are wa%$ m ?an o!rs4 ,! rake is also necess>y to prev5t ! sep>ation ( s& into co>s] & f9] p>ticles4 ,x is practically impossible to get filt] s& ! gra9s ( :i* are all ( ! same size4 ,:5 a filt] is wa%$ ! t5d5cy is = ! wa% wat] to g up 9 limit$ areas4 ,! l>g] s& gra9s t5d to collect at ^! po9ts :ile ! f9] gra9s collect 9 places :]e !re is no upw>d curr5t1 or :]e x is less rapid4 ,9 _m filt]s ?is t5d5cy is v /rong4 ,! revolv+ rake is necess>y to correct x1 & to keep ! s& ?or\ghly mix$1 o!rwise :5 a filt] is put 9 op]ation aft] wa%+1 ! frictional resi/ance ?r\gh ! co>se s& be+ less1 ! bulk ( ! wat] goes ?r\gh x1 ) ! result t a "p ( ! area1 & ! "p :i* is lea/ effici5t z a filt]1 passes ne>ly all ( ! wat]1 & ) inf]ior results4 ,9 ! ,jewell filt] provision is made = ! di/ribution ( ! wa% wat] ov] ! :ole area 9 ano!r way4 ,! /ra9]s h areas at ! surface am\nt+ to #a4b to #a4d p] c5t ( ! :ole area1 b ! wat] be=e rea*+ !m passes ?r\gh ?roats mu* small] 9 size ?an ! /ra9] outlets1 & am\nt+ 9 ! aggregate to only ab\t #j4jg p] c5t ( ! filt] area4 ,:5 wa%+ at a rate ( sev5 gallons p] squ>e foot p] m9ute1 wat] passes ?r\gh ^! necks at a velocity ( #bb feet p] second4 ,! friction & velocity head 9 pass+ ^! necks is e/imat$ to be ab\t #cj v]tical feet1 & is s mu* great] ?an ! friction ( ! outlets prop]1 & ( ! s&1 t ! wat] passes ?r\gh ea* /ra9] ) approximately ! same velocity1 & ! wa% wat] is equally di/ribut$ ov] ! :ole area ( ! bottom ( ! filt]4 ,?is result is accompli%$1 h[ev]1 at a great loss ( head 9 ! wa% wat]4 ,:5 a filt] is wa%$ f ! pressure-ma9s )\t sep>ate pump+1 ! pressure is usually suffici5t & !re is no disadvantage 9 ! arrangem5t4 ,:51 h[ev]1 ! wat] is specially pump$ = wa%+1 ! requir$ head is mu* great] ?an w\ld o!rwise be necess>y4 ,illu/ration3 ,,me*anical ,,filt]s ,,at ,,elmira1 ,n4 ,y4 ,,outlet ,,to ,,filt]s ,,) ,,controll] ,,& ,,pure-,,wat] ,,flume4 ,to face page #agd4 ,x w\ld n be possible to increase ! size ( ! necks1 !reby decreas+ ! friction1 )\t increas+ v l>gely ! size ( ! pipes 9 ! und]dra9age sy/em into :i* ! /ra9]s are fa/5$4 ,^! pipes are s small t dur+ wa%+ ! velocity 9 !m is ab\t #ac feet p] second1 & if ! ?roats ( ! necks 7 increas$ )\t also enl>g+ ^! pipes1 ! friction w\ld be s r$uc$ t mo/ ( ! wat] w\ld g ?r\gh ! necks ne>e/ ! supply1 ?us fail+ to rea* ! object to be atta9$4 ,a m rational sy/em w\ld be to increase ! sizes ( all ! wat]ways 9 ! outlet & wa%-wat] sy/em4 ,! ,jewell filt] is also provid$ ) a rake to keep ! s& mix$ dur+ wa%+1 z ?is is necess>y ev5 ) ! complete di/ribution ( wa%-wat] ov] ! area ( ! filt]4 ,bo? ! ,w>r5 & ! ,jewell filt]s are provid$ ) receptacles ?r\gh :i* ! wat] passes aft] receiv+ ! coagulant1 & be=e ent]+ ! filt]4 ,9 ! ,jewell filt] ! receptacle1 call$ a s$im5tation-bas91 is ( su* size z to hold z mu* wat] z is filt]$ 9 #ae m9utes4 ,9 ! ,w>r5 filt] ! receptacle is entirely indep5d5t & l>g]1 hold+ ab\t an h\r's supply4 ,! rates ( filtration us$ 9 ! exp]im5ts h rang$ f less ?an #ajj to ab\t #acj million gallons p] acre daily4 ,to employ a rate mu* high] ?an ?is involves ! use ( a mu* co>s] s&1 or an increase 9 ! height ( wat] ^u ! filt] to an impracticable ext5t4 ,!re w\ld seem to be no mat]ial advantage 9 ! use ( l[] rates )9 c]ta9 limits1 :ile ! co/ ( filt]s w\ld be greatly increas$4 ,! s& us$ 9 ! ,w>r5 filt]s has be5 cru%$ qu>tz4 ,9 ! ,jewell filt]s a silici\s s& f ,r$ ,w+1 ,m9n41 ) r\nd$ gra9s has be5 us$4 ,^! s&s are some:at co>s] ?an are commonly us$ 9 s& filt]s1 & ! uni=mity coeffici5ts are v l[4 ,x is necess>y to use s& ) ! v l[e/ uni=mity coeffici5ts to avoid ! sep>ation ( s& p>ticles accord+ to sizes z m5tion$ above1 & = ?is reason ! s& mu/ be select$ ) mu* great] c>e ?an is requir$ = s& filt]s4 ,illu/ration3 ,,plan ,,j ,,above ,,copp]4 ,,section ,,%[+ ,,filt] ,,dur+ ,,ord9>y ,,op]ation4 ,,fig4 #bc4--,,w>r5 ,,filt]3 ,,pittsburg ,,exp]im5ts4 ,,section ,,no4 #a4 ,illu/ration3 ,,plan ,,( ,,agitator1 ,,gutt] ,,ca/+s1 ,,etc4 ,,section ,,%[+ ,,filt] ,,dur+ ,,op]ation ,,( ,,wa%+4 ,,fig4 #bd4--,,w>r5 ,,filt]3 ,,pittsburg ,,exp]im5ts4 ,,section ,,no4 #b4 ,! r\nd-gra9$ s& is m readily & completely wa%$ ?an ! angul> cru%$ qu>tz4 ,x has be5 claim$ t ! cru%$ qu>tz is m effici5t z a filt]+ mat]ial1 b ! evid5ce ( ?is is n v cle>4 ,! am\nt ( wat] filt]$ by a filt] betwe5 wa%+s is1 9 a g5]al way1 ab\t ! same z t filt]$ by a s& filt] betwe5 scrap+s1 9 relation to its area4 ,! am\nt ( wat] requir$ = wa%+ is1 on an av]age1 ab\t equal to a v]tical column #e or #f feet high equal 9 area to ! area ( ! filt]1 exclusive ( wat] on ! top ( ! filt] wa/$ be=e ! curr5t is rev]s$4 ,) cle> wat]s1 z = in/ance1 ! ,allegh5y at l[ wat]1 ! am\nt ( wa%+ is almo/ directly proportional to ! am\nt ( sulphate ( alum9a us$4 ,) muddy wat]s ! sulphate ( alum9a requir$ is proportional to ! mud1 & ! frequ5cy ( wa%+ & ! am\nt ( wa%-wat] are proportional to bo?4 ,! am\nt ( wa%-wat] requir$ av]ages ab\t five p] c5t2 ) v muddy wat]s m is requir$4 ,at ,l\isville1 ) ! wor/ wat]s1 ! p] c5ts ( wa%-wat] rose at times to #cj p] c5t ( ! total quantity ( wat] filt]$4 ,! rate ( filtration ) me*anical filt]s %\ld be kept z con/ant z possible1 & c be regulat$ by devices simil> to ^? describ$ 9 connection ) s& filt]s4 ,ow+ to ! small] areas & capacities1 ! am\nts ( wat] to be h&l$ 9 ! units are small]1 & ! regulat+ devices are ?us small]1 & h always be5 made ( metal1 ei!r ca/ iron or copp]4 ,none ( ! devices employ$ 9 ! above-m5tion$ exp]im5ts has be5 entirely satisfactory 9 ?is respect4 ,! devices employ$ h be5 too small1 & ! wat] has gone ?r\gh at too high velocities to all[ close adju/m5t4 ,illu/ration3 ,,me*anical ,,filt]s ,,at ,,elmira1 ,n4 ,y4 ,,upp] ,,plat=m ,,& ,,g5]al ,,arrangem5t ,,( ,,filt]s4 ,to face page #agh4 ,z betwe5 ! two types ( filt]s1 ! ,jewell filt] requires a l>ge loss ( head4 ,! wat] has to be pump$ at a suffici5t elevation to rea* ! top ( a tank ab\t #ah feet high1 :ile ! efflu5t mu/ be drawn (f at ! extreme bottom4 ,! ,w>r5 filt] is mu* m economical 9 head1 ! plants at ,pittsburg & ,l\isville only requir+ ab\t #i feet f ! inlet to ! outlet4 ,! e>li] me*anical filt]s 7 usually con/ruct$ ( wr\ght iron or /eel plates4 ,m rec5tly wood5 tanks h be5 commonly employ$1 al?\gh /eel is reg>d$ z pref]able4 ,concrete or masonry tanks h be5 sugge/$1 b !y h n z yet be5 employ$4 ,,effici5cy ,,( ,,me*anical ,,filt]s4 ,! effici5cy ( me*anical filt]s dep5ds entirely ^u ! use ( coagulants4 ,)\t coagulants !y c only be us$ to remove v l>ge p>ticles4 ,! effici5cy ( ! filtration dep5ds mu* m ^u ! k9d1 & am\nt1 & me?od ( application ( coagulant ?an ^u ! arrangem5t ( ! filt]4 ,9 fact1 ! arrangem5ts ( ! filt] are m direct$ to ! conv5i5ce & economy ( op]ation & wa%+ ?an t[>ds ! effici5cy ( ! results4 ,! conditions :i* control ! effici5cy ( me*anical filt]s h be5 discuss$ 9 connection ) coagulation4 ,) suffici5t coagulant ! removal ( turbidity or mud is complete4 ,color also c be remov$ ) ^! filt]s4 ,! bact]ial effici5cies secur$ ) !m h be5 discuss$ at l5g? 9 connection ) ! ,pittsburg exp]im5ts4 ,) c>eful coagulation & manipulation x is possible to get #ih p] c5t bact]ial effici5cy )\t difficulty4 ,! results are some:at irregul>1 = reasons n z yet fully und]/ood4 ,on "s occasions high] bact]ial effici5cies are secur$ ) small] quantities ( coagulant1 :ile at o!r times ! effici5cies are less )\t app>5t reason4 ,!re seems to be a limit to ! bact]ial effici5cy :i* c be secur$ ) any am\nt ( sulphate ( alum9a & rapid filtration1 & x is d\btful if a plant c\ld be op]at$ to regul>ly secure z high a bact]ial effici5cy z #ii p] c5t ) any am\nt ( sulphate ( alum9a4 ,,pressure ,,filt]s4 ,pressure me*anical filt]s are con/ruct$ 9 entirely clos$ receptacles1 ?r\gh :i* ! wat] is =c$ "u pressure & n by gravity4 ,_m ( ! e>li] me*anical filt]s 7 ( ?is type4 ,9 small plants ?is sy/em has ! di/9ct advantage t ! wat] c be pump$ f a riv] or o!r s\rce ( supply ?r\gh a filt] direct to ! res]voir or into ! ma9s1 :ile any o!r sy/em w\ld involve a second pump+4 ,pressure filt]s are ext5sively us$ = hotel supplies1 etc41 :]e1 f ! conditions1 gravity filt]s are impossible4 ,! practical objections to ?is sy/em h be5 f\nd to be s great t x is r>ely us$ "u o!r conditions4 ,"s exp]im5ts 7 made at ,l\isville ) a filt] ( ?is type1 b !y 7 n long cont9u$1 & aside f !m !re is no precise in=mation z to :at c be accompli%$ ) filt]s ( ?is type4 ,,*apt] ,,xi4 ,,o!r ,,me?ods ,,( ,,filtration4 ,,worms ,,tile ,,sy/em4 ,?is sy/em1 inv5t$ & pat5t$ by ,director ,fis*] ( ! ,worms wat]-works1 consi/s ( ! filtration ( wat] ?r\gh artificial holl[ s&/one tiles1 made by heat+ a mixture ( brok5 glass & s&1 sift$ to det]m9$ sizes1 to a po9t j bel[ ! melt+-po9t ( ! glass1 9 suitable m\lds or =ms4 ,! glass s(t5s & adh]es to ! s&1 =m+ a /rong por\s sub/ance ?r\gh :i* wat] c be pass$4 ,^! tiles are made holl[ & are imm]s$ 9 ! wat] to be treat$1 ! efflu5t be+ remov$ f ! c5tre ( ea* tile4 ,!y are connect$ toge!r 9 gr\ps correspond+ 9 size to ! units ( a s&-filtration plant4 ,!y are wa%$ by a rev]se curr5t ( filt]$ wat]4 ,^! tiles h be5 us$ = "s ye>s at ,worms1 ,g]many1 & at a numb] ( small] places1 & 7 inve/igat$ exp]im5tally at ,pittsburg4 ,"s difficulty has be5 exp]i5c$ 9 gett+ tiles ) pores small en\gh to yield an efflu5t ( ! desir$ purity1 & at ! same "t l>ge en\gh to all[ a reasonable quantity ( wat] to pass4 ,9 fact1 ) o!r ?an q cle> wat]s1 x has n be5 f\nd feasible to accompli% bo? objects at ! same "t1 & x has be5 necess>y to treat ! wat] ) coagulants & prelim9>y s$im5tation or filtration be=e apply+ x to ! tiles4 ,! problem ( mak+ ! jo9ts betwe5 ! tiles & ! collection-pipes wat]-tight :5 surr\nd$ by ! raw wat] also is a matt] ( "s difficulty4 ,,! ,,use ,,( ,,asbe/os4 ,x has be5 sugge/$ by ,mr4 ,p4 ,a4 ,maign5 t ! surface ( s& filt]s %\ld be cov]$ ) a ?9 lay] ( asbe/os1 appli$ 9 ! =m ( a pulp1 ) ! fir/ wat] put onto ! filt] aft] scrap+4 ,! asbe/os =ms a sort ( a pap] on ! s& :i* int]cepts ! s$im5t ( ! pass+ wat]4 ,! advantage ( ! process is 9 ! clean+4 ,:5 dri$ to ! "r consi/5cy ?is asbe/os c be roll$ up l a c>pet1 & tak5 f ! filt] )\t remov+ any ( ! s&4 ,?is proc$ure is almo/ id5tical ) t :i* has occurr$ naturally 9 iron-removal plants1 :]e alg gr[ 9 ! wat] ^u ! filt]s1 & =m a fibr\s sub/ance ) ! f]ric oxide remov$ f ! wat]1 :i* c be roll$ up & remov$ 9 ! same way z ! asbe/os4 ,! advantages ( ! process1 f an economical /&po9t1 are less cle>4 ,,filt]s ,,us+ ,,high ,,rates ,,( ,,filtration ,,)\t ,,coagulants4 ,num]\s filt]s h be5 sugge/$1 & a few h be5 con/ruct$ = ! use ( mu* high] rates ( filtration ?an are usually employ$ ) s& filt]s1 b )\t ! use ( coagulants4 ,! results obta9$ dep5d ^u ! requirem5ts & ^u ! "* ( ! raw wat]4 ,if a res]voir wat] conta9s an alg gr[?1 x c (t5 be remov$ by a co>se & rapid filt]4 ,! organisms 9 ?is case are _m times l>g] ?an ! bact]ia1 & _m times l>g] ?an ! clay p>ticles :i* con/itute turbidity4 ,! requirem5ts 9 ?is case are r 9 ! nature ( /ra9+ ?an ( filtration4 ,! conditions necess>y = ! removal ( bact]ia & turbidity are v well und]/ood1 & x c be /at$ ) ! utmo/ confid5ce t no sy/em ( filtration ?r\gh s& at rates _m times z high z are us$ 9 ord9>y s& filtration1 & )\t ! use ( coagulants1 w be satisfactory :]e ei!r bact]ial effici5cy or cl>ification is requir$4 ,! application ( su* sy/ems ( filtration w\ld !re=e seem to be some:at limit$4 ,illu/ration3 ,,remov+ ,,dirty ,,asbe/os ,,cov]+ ,,f ,,an ,,exp]im5tal ,,filt]4 ,,maign5 ,,sy/em4 ,to face page #ahb4 ,,h\sehold ,,filt]s4 ,! subject ( h\sehold filt]s is a some:at broad "o1 z ! v>iety 9 ^! filt]s is ev5 great] ?an 9 ! l>g] filt]s1 & ! range 9 ! results to be expect$ f !m is at lea/ z great4 ,i %all only attempt to indicate "h "s ( ! lead+ po9ts 9 reg>d to !m4 ,h\sehold filt]s may be us$ to remove mud or iron ru/ f ! tap wat]1 or to remove ! bact]ia 9 case ! latt] is sewage-pollut$1 or to d bo? at once4 ,p]haps (t5] !y are us$ simply because x is believ$ to be ! prop] ?+1 & )\t any cle> conception ei!r ( ! desir$ result or ! way 9 :i* x c be accompli%$4 ,i %all consid] !m only 9 _! relations to ! removal ( bact]ia1 z ,i cr$it ! p :o employ !m ) be+ suffici5tly good judges ( _! effici5cy 9 remov+ visible s$im5t4 ,9 ! fir/ place1 z a g5]al rule1 :i* has v few if any exceptions1 we may say t all small filt]s :i* all[ a good /ream ( wat] to pass d n remove ! bact]ia4 ,! reason = ?is is simply t a mat]ial op5 en\gh to all[ wat] to pass ?r\gh x rapidly is n f9e en\gh to /op su* small bodies z ! bact]ia4 ,! filt]s :i* are s (t5 sold z 8g]m-pro(10 consi/+ ( s&1 animal *>coal1 wire-clo?1 filt]-pap]1 etc41 d n af=d protection aga9/ any unheal?y qualities :i* !re may be 9 ! raw wat]4 ,animal *>coal removes color )\t reta9+ ! f> m objectionable bact]ia4 ,! o!r h\sehold filt]s h filt]+ mat]ials ( mu* f9] gra91 unglaz$ porcela9 & natural s&/one be+ ! mo/ prom95t mat]ials1 :ile infusorial e>? is also us$4 ,! small] sizes ( ^! filt]s all[ wat] to pass only drop by drop1 & :5 a fair /ream passes !m ! filt]s h consid]able filt]+ area 7z a s]ies ( filt]-tubes connect$ toge!r74 ,on acc\nt ( _! sl[ action1 filt]s ( ?is class are1 z a rule1 provid$ ) /orage res]voirs s t filt]$ wat] to ! capacity ( ! res]voir c be drawn rapidly 7provid$ ! calls d n come too (t574 ,"s ( ^! filt]s are ne>ly g]m-pro(1 & are comp>able 9 _! effici5cy to l>ge s&-filt]s4 ,!re is no %>p l9e betwe5 ! filt]s :i* /op & :i* d n /op ! bact]ia2 b 9 g5]al ! rule t a filt] :i* works rapidly 9 proportion to its size does n d s1 & vice v]sa1 w be f\nd correct4 ,9 ?9k+ ( ! effici5cy ( h\sehold filt]s we mu/ di/+ui% betwe5 ! filt] c>efully prep>$ = an aw>d at an exhibition & ! filt] ( ! same k9d do+ its av]age daily "w 9 ! kit*54 ,if we c\ld be sure 9 ! latt] case t an unbrok5 lay] ( f9e s&/one or porcela9 0 always betwe5 ourselves & ! raw tap-wat] we c\ld feel comp>atively safe4 ,! manufactur]s ( ! filt]s claim t leaky jo9ts1 crack$ tubes1 etc41 are impossible2 b ,i w\ld urge ^u ! p us+ wat] filt]$ 9 ?is way t !y p]sonally assure !mselves t ?is is actually ! case ) _! own filt]s1 = 9 case any su* accid5t %\ld happ5 ! consequ5ces might be mo/ unpleasant4 ,! increas$ yield ( a filt] due to a leaky jo9t is sure n to decrease x 9 favor ) ! cook1 :o is probably q out ( pati5ce ) x because x works s sl[ly1 t is1 9 case x is good = any?+4 ,! op]ation ( h\sehold filt]s is necess>ily1 ) r>e exceptions1 left to ! kit*5-girl & luck4 ,sci5tific sup]vision is practically impossible4 ,) a l>ge filt]1 on ! o!r h&1 conc5trat+ all ! filt]s = ! city at a s+le po9t1 a compet5t man c be employ$ to run !m 9 ! be/-kn[n way2 & if desir$1 & z is actually done 9 v _m places1 an entirely indep5d5t bact]iologi/ c be employ$ to det]m9e ! effici5cy ( filtration4 ,) ! me?ods ( exam9ation n[ available1 & a little c>e 9 select+ ! times & places ( collect+ ! samples1 x is q impossible = a filt]-sup]9t5d5t to deliv] a poor efflu5t v (t5 or = any consid]able l5g? ( "t )\t be+ caught4 ,! safety ( prop]ly-conduct$ c5tral filtration is ?us inf9itely great] ?an t f ev5 ! be/ h\sehold filt]s4 ,fur!r1 x may be d\bt$ :e!r an infect$ wat] c be s5t into e h\se 9 ! city to be us$ = wa%+ & all ! purposes to :i* wat] is put except dr9k+1 )\t caus+ disease1 al?\gh less ?an x w\ld if x 7 also us$ = dr9k+4 ,! use ( h\sehold filt]s mu/ be reg>d$ z a some:at desp]ate me?od ( avoid+ "s ( ! bad consequ5ces ( a pollut$ wat]-supply1 & !y are adopt$ = ! mo/ "p by citiz5s :o 9 "s measure realize ! dang]s f bad wat]1 b :o _c p]suade _! fell[-citiz5s to a m ?or\gh & adequate solution ( ! problem4 ,su* citiz5s1 by ! use ( ! be/ filt]s1 & by c>efully wat*+ _! action1 or by hav+ _! dr9k+-wat] boil$1 c avoid ! pr9cipal dang]s f bad wat]1 b _! vigilance does n protect _! m c>eless neighbors4 ,,*apt] ,,xii4 ,,removal ,,( ,,iron ,,f ,,gr\nd-,,wat]s4 ,! filtration ( gr\nd-wat]s is a comp>atively rec5t developm5t4 ,gr\nd-wat]s are filt]$ by _! passage ?r\gh soil g5]ally mu* m p]fectly ?an x is possible to filt] o!r wat]s1 & any fur!r filtration ( !m is useless4 ,su* wat]s1 h[ev]1 occasionally conta9 iron 9 solution z f]r\s c>bonate4 ,wat]s conta9+ iron h be5 us$ z m9]al wat]s = a v long "t4 ,su* wat]s h an a/r+5t ta/e1 & h be5 e/eem$ = "s purposes4 ,z ord9>y wat]-supplies1 h[ev]1 !y are objectionable4 ,! iron deposits 9 ! pipes :5 ! curr5t is sl[1 & is flu%$ out :5 x is rapid1 & makes ! wat] turbid & disagreeable2 & /ill worse1 ! iron (t5 gets ?r\gh ! pipe-sy/em 9 solution1 & deposits 9 ! wa%-tub1 color+ ! l95 a ru/y br[n & q spoil+ x4 ,an organism call$ cr5o?rix gr[s 9 pipes c>ry+ wat]s conta9+ iron1 & aft] a :ile ?is organism dies1 & decomposes1 & gives rise to v disagreeable ta/es & odors4 ,x ?us happ5s t gr\nd-wat]s conta9+ iron are unsatisfactory z public wat]-supplies1 & are s\rces ( s]i\s compla9t4 ,,am\nt ,,( ,,iron ,,requir$ ,,to ,,r5d] ,,wat] ,,objectionable4 ,?ree hundr$?s ( a "p 9 #ajj1jjj ( metallic iron v r>ely precipitate or cause any tr\ble4 ,five hundr$?s occasionally precipitate1 & ?is am\nt may be tak5 z ab\t ! all[able limit ( iron 9 a satisfactory wat]4 ,"o t5? ( a "p is q sure to precipitate & give rise to s]i\s compla9t4 ,two or ?ree t5?s make ! wat] entirely unsuitable = laundry purposes1 & are o!rwise s]i\sly objectionable1 & w h>dly be tol]at$ by a community4 ,"u "s conditions gr\nd-wat]s c>ry z mu* z #a "p 9 #ajj1jjj ( iron1 & su* wat]s are h>dly usable4 ,9 iron-removal plants an efflu5t conta9+ less ?an #j4je is reg>d$ z satisfactory4 ,"o conta9+ less ?an #j4jb1 z is ! case ) _m plants1 is all t c be desir$4 ,! p]c5tage ( removal is ( no significance1 b only ! am\nt left 9 ! efflu5t4 ,,cause ,,( ,,iron ,,9 ,,gr\nd-,,wat]s4 ,natural s&s1 gravels1 & rocks almo/ always conta9 iron1 (t5 9 consid]able am\nt4 ,! iron is usually comb9$ ) oxyg5 z f]ric oxide1 & 9 ?is condition x is insoluble 9 wat]4 ,wat] pass+ ?r\gh iron conta9+ mat]ials w n ord9>ily take up iron4 ,:51 h[ev]1 ! wat] conta9s a l>ge am\nt ( organic matt] 9 solution1 ?is organic matt] takes "p ( ! oxyg5 away f ! iron1 & r$uces ! f]ric oxide to f]r\s oxide4 ,! f]r\s oxide comb9es ) c>bonic acid1 always pres5t "u ^! conditions1 =m+ f]r\s c>bonate1 :i* is soluble & :i* goes into solution4 ,surface-wat]s ne>ly always c>ry free oxyg51 & :5 su* wat]s ent] ! gr\nd !y c>ry oxyg5 ) !m1 & ! organic matt]s 9 ! wat] use up ! free oxyg5 be=e !y comm5ce to take oxyg5 away f ! iron ( ! gr\nd4 ,x is ?us only 9 ! pres5ce ( organic matt]s1 & 9 ! abs5ce ( free oxyg51 t ! solution ( iron is possible4 ,x sometimes happ5s t ! organic matt]s :i* r$uce ! iron are conta9$ 9 ! soil itself1 9 :i* case iron may be tak5 up ev5 by wat] orig9ally v pure1 z = in/ance1 by ra9-wat]4 ,g5]ally speak+1 iron is ev]y:]e pres5t 9 suffici5t quantity 9 ! /rata f :i* gr\nd-wat]s are obta9$1 & :]ev] ! conditions ( ! organic matt]s & oxyg5 necess>y = solution occur1 iron-conta9+ wat]s are secur$1 & ! iron is usually pres5t 9 ! e>? 9 su* quantity t ! wat] c dissolve z mu* z x w take up = a long s]ies ( ye>s1 or = c5turies1 )\t exhau/+ ! supply4 ,!re is ?us little prospect ( improvem5t ( su* wat]s f exhau/ion ( ! supply ( iron4 ,! circum/ances :i* control ! solution ( iron are v complicat$ & difficult to det]m9e4 ,wells ne> a riv]1 & draw+ _! wat] l>gely f x by seepage1 are apt to yield a wat] conta9+ iron soon] or lat]1 especially :]e ! riv]-wat] c>ries a l>ge am\nt ( organic matt] 9 solution4 ,wat]s drawn f ext5sive gravel deposits1 9 :i* ! wat] is r5ew$ pr9cipally by ! ra9fall ^u ! surface ( ! deposits !mselves1 (t5 rema9 entirely free f iron indef9itely4 ,! ra9-wat] is almo/ free f organic matt]1 & ! air is able to take c>e ( decompos+ organic matt]s 9 ! surface soil1 & bel[ ?is !re are no accumulations ( organic matt] suffici5t to cause ! solution ( iron4 ,"u o!r conditions !re are subt]ranean s\rces ( organic matt] :i* result 9 ! solution ( iron "u conditions :i*1 on ! surface1 appe> mo/ favorable = secur+ good wat]4 ,wells are (t5 us$ = _m ye>s )\t develop+ iron1 :5 sudd5ly iron w appe>4 ,?is appe>ance ( iron is (t5 connect$ ) increas+ consumption ( wat]4 ,9 "s cases x may result f draw+ wat] f areas n previ\sly drawn ^u4 ,:5 iron once makes its appe>ance 9 a wat]1 x seldom disappe>s completely aft]w>d1 al?\gh x (t5 fluctuates widely at diff]5t seasons ( ! ye> & "u diff]5t conditions ( pump+4 ,9 "s cases a decrease 9 ! quantity ( iron is not$ aft] a numb] ( ye>s1 b 9 o!r cases ?is does n happ54 ,9 a few cases manganese has be5 f\nd 9 gr\nd-wat]s4 ,manganese 9 wat] behaves mu* l iron1 b !re are "s po9ts ( diff]5ce1 s t ! possibility ( ! pres5ce ( ?is sub/ance %\ld be borne 9 m9d4 ,iron-conta9+ wat]s are g5]ally entirely free f oxyg51 & :5 fir/ drawn f ! gr\nd !y are bright & cle> & d n diff] 9 appe>ance f o!r gr\nd-wat]s4 ,on exposure to ! air !y quickly become turbid f ! oxidation ( ! iron1 & its precipitation z f]ric hydrate4 ,at ,we/ ,sup]ior1 ,wiscons91 a wat] 0 f\nd conta9+ bo? iron & dissolv$ oxyg54 ,x 0 turbid z pump$ f ! well4 ,?is condition ( affairs seem$ abnormal1 b 0 repeat$ly *eck$1 & ! !ory 0 advanc$ by ,mr4 ,r4 ,s4 ,we/on1 :o made ! obs]vations1 t x result$ f a mixture 9 ! wells ( two entirely diff]5t wat]s1 namely1 a wat] result+ f ! ra9fall on s& deposits back ( ! wells1 conta9+ dissolv$ oxyg5 & no iron1 & wat] f ! lake :i* _h seep$ ?r\gh ! s&1 & :i* conta9$ a consid]able am\nt ( iron 9 solution b no dissolv$ oxyg54 ,! wells ?us drew wat] f opposite directions1 & ! two wat]s 7 entirely diff]5t 9 "*1 & ! mixture ?us _h a composition :i* w\ld n h be5 possible 9 a wat] all ( :i* came f a s+le s\rce4 ,,treatm5t ,,( ,,iron-,,conta9+ ,,wat]s4 ,! removal ( iron f gr\nd-wat] is ord9>ily a v simple proc$ure4 ,x is simply necess>y to a]ate ! wat]1 by :i* process ! f]r\s c>bonate is decompos$1 & oxidiz$ ) ! =mation ( f]ric hydrate1 :i* =ms a floccul5t precipitate & is readily remov$ by filtration4 ,! a]ation requir$ v>ies 9 diff]5t cases4 ,! quantity ( oxyg5 requir$ to oxidize ! iron is only a small fraction ( ! am\nt :i* wat] w dissolve1 & all[+ wat] to simply fall ?r\gh ! air = a few feet 9 f9e /reams w usually supply sev]al times z mu* oxyg5 z is necess>y = ?is purpose4 ,a]at+ devices ( ?is k9d h prov$ suffici5t 9 a numb] ( cases1 z at ,f> ,rockaway1 ,l4 ,i41 & at ,r$ ,bank1 ,n4 ,j4 ,9 "s cases1 h[ev]1 a fur!r a]ation is necess>y1 n = ! purpose ( gett+ m oxyg5 into ! wat]1 b to get ! excess ( c>bonic acid out ( x4 ,c>bonic acid seems to ret>d 9 "s way ! oxidation ( ! iron1 & x is occasionally pres5t 9 gr\nd-wat]s 9 consid]able quantity1 & q s]i\sly int]f]es ) ! process4 ,x c be remov$ suffici5tly by a]ation1 b ! necess>y am\nt ( exposure to air is mu* great] ?an t requir$ to simply introduce oxyg54 ,coke-t[]s h sometimes be5 us$ = ?is purpose4 ,! t[]s are fill$ ) co>se coke & h op5 sides1 & wat] is spr9kl$ ov] ! tops ( !m & all[$ to drip ?r\gh to ! bottoms4 ,9 g5]al ! simple exposure ( wat] to ! air = a suffici5t l5g? ( "t1 9 any =m ( app>atus or simply 9 op5 *annels1 w accompli% ! desir$ results4 ,mr4 ,h4 ,w4 ,cl>k#de has call$ att5tion to ! fact t 9 "s cases coke seems to h a direct *emical action ^u ! wat] :i* is entirely indep5d5t ( its a]at+ effect4 ,9 8 exp]im5ts !re seem$ to be "s prop]ty 9 ! coke :i* caus$ ! iron to oxidize & flocculate 9 _m cases :5 x refus$ to d s ) simple a]ation & filtration4 ,:5 ! "r conditions are rea*$ ! oxidation ( ! iron is v rapid1 & x sep>ates out 9 flakes ( su* size t !y c be remov$ by filtration at almo/ any practicable rate4 ,me*anical filt]s h be5 us$ = ?is purpose1 ) rates ( filtration ( #ajj million gallons p] acre daily4 ,9 ,g]many1 :]e plants = ! removal ( iron are q common1 modifi$ =ms ( s& filt]s h usually be5 employ$ :i* h be5 op]at$ at rates up to #be million gallons p] acre daily4 ,9 exp]im5ts made by ! ,massa*usetts ,/ate ,bo>d ( ,heal? rates f #aj to #be million gallons p] acre daily h be5 employ$4 ,! s& us$ = filtration may appropriately be some:at co>s] ?an w\ld be us$ = treat+ surface-wat]s1 & ! ?ickness ( ! s& lay] may be r$uc$4 ,ow+ to ! high] rates ! und]dra9age sy/em mu/ be m ample ?an is o!rwise necess>y4 ,! rate ( filtration employ$ is usually n a matt] ( vital importance1 b by select+ a rate t is n too high x is possible to use a mod]ate loss ( head4 ,x is ?us n necess>y to clean ! filt]s too (t51 & ! exp5ses ( op]ation are n z high z ) an extreme rate4 ,9 "s cases x is desir$ to accompli% o!r results ?an ! removal ( iron by filtration1 & ?is may lead to ! selection ( a rate l[] ?an w\ld o!rwise be us$4 ,"u normal conditions ( op]ation all ( ! iron sep>ates on ! top ( ! s&4 ,no appreciable am\nt ( x p5etrates ! s& at all4 ,) op5 filt]s at ,f> ,rockaway & at ,r$ ,bank !re is an alg gr[? 9 ! wat] ^u ! filt]s :i*1 ) ! iron1 =ms a mat ^u ! surface ( ! filt]2 & :5 ! filt] is put out ( s]vice & all[$ to p>tially dry1 ?is mat c be roll$ up l a c>pet & ?r[n (f )\t remov+ any s&1 & ! filt]s h be5 9 use = sev]al ye>s )\t r5ew+ any s& & )\t any important decrease 9 ! ?ickness ( ! s& lay]4 ,"s wat]s conta9 iron 9 su* a =m t x _c be successfully remov$ 9 ?is mann]4 ,?us at ,read+1 ,mass41 x 0 report$ by ,dr4 ,?omas ,m4 ,dr[n t ! iron 0 pres5t 9 ! =m ( f]r\s sulphate in/ead ( f]r\s c>bonate1 & t x 0 n capable ( be+ sep>at$ by simple a]ation & filtration4 ,a ,w>r5 me*anical filt] 0 in/all$1 & ! wat] is treat$ by a]ation & ) ! addition ( lime & alum4 ,! co/ ( ! process is !reby mu* increas$1 & ! h>dness ( ! wat] is increas$ ?reefold4 ,sev]al o!r cases h be5 report$ :]e x 0 believ$ t simple a]ation & filtration 7 inadequate2 b ! advantages ( ! simple proc$ure are s great z to make x wor? a v c>eful /udy to det]m9e if m complete a]ation1 or ! use ( coke-t[]s & p]haps sl[] filtration1 w\ld n s]ve 9 ^! cases )\t resort+ to ! use ( *emicals & _! att5dant disadvantages4 ,,iron-,,removal ,,plants ,,9 ,,op]ation4 ,iron-removal plants are n[ 9 use at ,am/]dam & ,! ,hague 9 ,holl&1 at ,cop5hag5 9 ,d5m>k1 at ,kiel1 ,*>lott5burg1 ,leipzig1 ,halle1 & _m o!r places 9 ,g]many2 at ,read+1 ,mass42 ,f> ,rockaway1 ,l4 ,i42 ,r$ ,bank1 ,asbury ,p>k1 ,atlantic ,highl&s1 & ,keyport1 ,n4 ,j4 ,among ! e>lie/ plants = ! removal ( iron 7 ! filt]s con/ruct$ at ,am/]dam & ,! ,hague 9 ,holl&4 ,at ,am/]dam ! wat] is d]iv$ f op5 canals 9 ! dunes dra9+ a l>ge area4 ,! wat] has its orig9 9 ! ra9-wat] fall+ ^u ! s&4 ,! s& is v f9e & conta9s organic matt] 9 suffici5t am\nt s t ! gr\nd-wat] is impregnat$ ) iron4 ,9 fl[+ to a c5tral po9t 9 ! op5 canals ! wat] becomes a]at$ & ! iron oxidiz$4 ,!re are also alg gr[?s 9 ! wat] :i* p]haps aid ! process4 ,s& filt]s ( ord9>y con/ruction are us$1 & remove bo? ! iron & ! alg1 & ! rate ( filtration is n high] ?an is usually us$ 9 ! treatm5t ( riv]-wat]s1 al?\gh x c\ld probably be l>gely increas$ )\t detrim5t to ! supply4 ,! works at ,! ,hague are v simil> to ^? at ,am/]dam1 b cov]$ collectors are us$ to supplem5t ! op5 canals4 ,bo? ( ^! plants 7 built be=e mu* 0 kn[n ab\t iron 9 gr\nd-wat]s & ! means = its removal1 b !y h p]=m$ _! "w ) uni=mly satisfactory results4 ,9 ! m rec5t ,g]man works v>i\s a]at+ devices are employ$1 & filt]s simil> 9 g5]al con/ruction to ord9>y s& filt]s1 b ) l>g] connections suit$ to v high rates ( filtration1 are employ$4 ,! plant at ,asbury ,p>k 0 ! fir/ ( importance con/ruct$ 9 ,am]ica4 ,! wat] is rais$ f wells f #djj to #aajj feet deep by compress$ air by a ,pohle lift4 ,x is deliv]$ into a squ>e masonry receiv+-bas9 hold+ "s h\rs' supply4 ,! a]ation ( ! wat] by ?is means is v complete4 ,x is aft]w>ds pump$ ?r\gh ,cont95tal pressure filt]s direct into ! s]vice-pipes4 ,! res]voir = ! a]at$ wat] 0 n a "p ( ! orig9al plant1 b 0 add$ aft]w>ds to facilitate op]ation1 & to give m complete a]ation be=e filtration4 ,at ,f> ,rockaway1 ,l4 ,i41 ! wat] is lift$ f wells by a ,wor?+ton ,pump1 & is dis*>g$ ov] ! bell ( a v]tical #af-;in* pipe1 f :i* x falls ?r\gh ! air to ! wat] 9 a receiv+ *amb] ar\nd x4 ,! simple fall ?r\gh ! air a]ates ! wat] suffici5tly4 ,f ! receiv+-*amb] ! wat] is tak5 to ei!r or bo? ( two filt]s1 ea* ) an area ( #bj1jjj squ>e feet4 ,^! filt]s are op51 ) brick walls & concrete bottoms1 ?ree feet ( s& & "o foot ( gravel1 & ! und]dra9s are ( ! usual type4 ,! wat] fl[s ?r\gh regulator-*amb]s to a well #be feet 9 diamet] & #ab feet deep1 f :i* x is pump$ to a /&-pipe 9 ! t[n4 ,! plant 0 built to treat easily ?ree million gallons p] day1 & has occasionally treat$ a l>g] quantity4 ,ei!r filt] yields ! :ole supply :ile ! o!r is be+ clean$4 ,! rate ( filtration 9 ?is case 0 made l[] ?an w\ld h o!rwise be5 necess>y1 z !re 0 an alt]nate supply1 namely1 ! wat] f two brooks1 :i* c\ld be us$ on occasions1 & to purify :i* a l[] rate ( filtration 0 reg>d$ necess>y1 ?an w\ld h be5 requir$ = ! well-wat]4 ,! removal ( iron is complete4 ,illu/ration3 ,,fig4 #be4 ,! plant ( ! ,rumson ,improvem5t ,company at ,r$ ,bank1 ,n4 ,j41 is q simil> to t at ,f> ,rockaway1 b is mu* small]4 ,! outlet is a #f-;in* pipe p]=at$ ) #a_/d-;in* holes :i* ?r[s ! wat] out 9 a p9e-tree %ape to ! receiv+-tank1 ?or\ghly a]at+ x4 ,ea* ( ! two filt]s has #ggj squ>e feet ( area4 ,! filt]+ mat]ial is ?ree feet ( bea* s&4 ,f ! regulator-*amb] ! wat] fl[s to a circul> well #ah feet 9 diamet]1 cov]$ by a brick dome & hold+ #ag1jjj gallons1 f :i* x is pump$ to ! /&-pipe4 ,ei!r ( ! filt]s w treat t5 ?\s& gallons ( wat] p] h\r1 :i* is equal to ! capacity ( ! pumps2 & z ! consumption is consid]ably less ?an ?is figure1 !y are only 9 use = a "p ( ea* day1 ! numb] ( h\rs dep5d+ ^u ! consumption4 ,^! filt]s are %[n by ! accompany+ plan4 ,! co/ ( ! "w 0 z foll[s3 ,filt]s & pure-wat] res]voir1 ) pip+ & dra9s complete #c1gii4dg ,new pump & connections #dib4fh ,eng9e]+ & sup]9t5d5ce #iib4ia --------- ,total co/ ( plant #e1bhe4jf ,! eng9e] :o op]ates ! pumps takes c>e ( ! filt]s1 & no additional labor has be5 requir$4 ,! entire co/ ( op]ation is ?us repres5t$ by ! additional coal requir$ = ! prelim9>y lift f ! wells to ! filt]s4 ,! efflu5t is always free f iron4 ,! plant at ,read+1#df ,mass41 0 in/all$ by ! ,cumb]l& ,manufactur+ ,company1 & comb9es a]ation1 treatm5t ) lime & sulphate ( alum9a & rapid filtration4 ,! a]ation is effect$ by pump+ air ?r\gh ! wat]1 aft] ! wat] has receiv$ ! lime4 ,x aft]w>ds receives sulphate ( alum9a & passes to a settl+-tank hold+ #dj1jjj gallons1 9 :i* ! wat] rema9s = ab\t an h\r4 ,!re are six filt]s ( ! ,w>r5 type1 ea* ) an effective filt]+ area ( #ed squ>e feet4 ,! co/ ( coagulant is consid]able4 ,! *ief disadvantage ( ! process is t x h>d5s ! wat]1 :i* is naturally s(t4 ,f ! completion ( ! plant 9 ,july1 #ahif1 to ! end ( ! ye> ! h>dness ( ! wat] 0 increas$1 accord+ to analyses ( ! ,/ate ,bo>d ( ,heal?1 f #d4a to #aa4c p>ts 9 #ajj1jjj1 & = ! ye> #ahig ! increase 0 f #d4j to #ab4g4 ,! iron1 :i* is pres5t 9 ! raw wat] to ! ext5t ( ab\t #j4bf "p 9 #ajj1jjj1 is remov$ suffici5tly at all times4 ,prior to ! erection ( ?is plant ,mr4 ,desmond ,fitz,gerald advis$ a]ation foll[$ by s$im5tation 9 two res]voirs hold+ half a million gallons ea*1 & by rapid filtration4 ,mr4 ,bancr(t /ates t 9 8 op9ion1 if ! res]voir recomm5d$ by ,mr4 ,fitz,gerald _h be5 built1 ! filt]s c\ld be run ) v little or no coagulation1 & consequ5tly )\t increase 9 h>dness1 :i* is ! mo/ obvi\s disadvantage to ! proc$ure4 ,! nom9al capacity ( ! plant is "o million gallons1 & ! av]age consumption ab\t #bjj1jjj gallons daily4 ,! plant at ,keyport1 ,n4 ,j41 is simil>1 b small]4 ,,*apt] ,,xiii4 ,,treatm5t ,,( ,,wat]s4 ,hav+ n[ review$ ! mo/ important me?ods 9 use = ! treatm5t ( wat]s1 we may take a g5]al view ( _! application to v>i\s classes ( wat]s4 ,diff]5t raw wat]s v>y s mu*1 & ! requirem5ts ( filtration are s diff]5t1 t x is n possible to outl9e any g5]al proc$ure or comb9ation ( proc$ures1 b ea* problem mu/ be tak5 up by itself4 ,nev]!less1 "s g5]al sugge/ions may be ( s]vice4 ,9 ! fir/ place1 we may consid] ! case ( wat]s conta9+ v l>ge quantities ( oxidizable organic matt]4 ,su* wat]s are obta9$ f "s res]voirs conta9+ v active vegetable & animal gr[?s1 or f riv]s receiv+ l>ge am\nts ( sewage4 ,wat]s ( bo? ( ^! classes are1 if possible1 to be avoid$ = public wat]-supplies4 ,:5 circum/ances require _! use1 !y c be/ be treat$ by int]mitt5t filtration1 ?is process be+ be/ adapt$ to ! de/ruction by oxyg5 ( excessive quantities ( organic matt]4 ,:]e ! pollution is less1 s t ! dissolv$ oxyg5 conta9$ 9 ! raw wat] is suffici5t = ! oxidation ( ! organic matt]s1 cont9u\s filtration w give sub/antially z good results z int]mitt5t filtration1 & 9 o!r respects x has important advantages4 ,! application ( int]mitt5t filtration = ! treatm5t ( public wat]-supplies is ?us some:at limit$1 &1 z a matt] ( fact1 x has be5 us$ 9 only a few cases4 ,= ! treatm5t ( v highly pollut$ wat]s d\ble filtration has be5 us$ 9 a numb] ( cases1 notably by ! ,gr& ,junction ,company at ,london1 at ,s*i$am 9 ,holl&1 & at ,brem5 & ,altona 9 ,g]many4 ,at ! two fir/-m5tion$ places two sep>ate sy/ems ( filt]s are provid$ diff]+ some:at 9 con/ruction1 ! fir/ filt]s be+ at a high] level ?an ! aft] filt]s4 ,! fir/ filt]s supply wat] ( comp>ative purity1 & v con/ant composition1 to ! aft] filt]s1 :i* are able to treat x ) great effici5cy & at v l[ op]at+ co/4 ,?is proc$ure is probably ! mo/ p]fect :i* has be5 us$ = ! removal ( disease-produc+ qualities f highly pollut$ wat]s2 & ! co/ ( ! process may n be z mu* great] ?an t ( simple filtration z w\ld at fir/ appe>1 because ! co/ ( clean+ ! aft] filt]s is m]ely nom9al1 & ! att5dance1 pump+1 etc41 are practically common to bo? sets ( filt]s1 & are n mat]ially great] ?an !y w\ld be = a s+le set4 ,= v bad wat]s ! fir/ filt]s might appropriately be int]mitt5t1 :ile ! aft] filt]s %\ld be cont9u\s4 ,?is 0 ! proc$ure orig9ally int5d$ = ,lawr5ce1 b ! int]mitt5t filt] fir/ con/ruct$ yield$ su* v good results t x has n be5 consid]$ necess>y to complete ! plant z orig9ally project$4 ,at ,brem5 & at ,altona a diff]5t proc$ure has be5 adopt$4 ,! filt]s are all ^u ! same level1 & ( ! same con/ruction4 ,:5 a filt] is put 9 s]vice ! efflu5t f x1 in/ead ( be+ tak5 to ! pure-wat] res]voir1 is tak5 to ano!r filt] :i* has already be5 "s "t 9 s]vice4 ,aft] ! fir/ filt] has be5 9 op]ation = "s "t its efflu5t is tak5 to ! pure-wat] res]voir1 & 9 turn x is suppli$ ) ! efflu5t f a filt] m rec5tly clean$4 ,! loss ( head ( wat] pass+ a fre%ly clean$ filt] is comp>atively slight1 & ! wat] ( ! second filt] is all[$ to fall a few in*es bel[ ! high-wat] m>k1 at :i* level x w take ! efflu5t f ! o!r filt]4 ,! connections betwe5 ! filt]s are made by siphons ( l>ge pipe1 ! summits ( :i* are consid]ably above ! high-wat] l9e4 ,^! siphons are fill$ by exhau/+ ! air1 & :5 op5$ to ! air !re is no possibility ( a fl[ ( wat] ?r\gh !m4 ,! process has giv5 extremely good results 9 practice1 yield+ efflu5ts ( ! v greate/ purity & at a q mod]ate co/ ( op]ation4 ,an objection to ! me?od is ! possible fill+ ( a siphon "s "t :5 ! wat] /&+ ^u ! aft]-filt] is high] ?an t 9 ! pure-wat] well ( ! =e-filt]1 & :ile ! =e-filt] is connect$ ) ! pure-wat] res]voir4 ,su* a connection w\ld s5d unfilt]$ wat] into ! pure-wat] res]voir direct4 ,i d n "k t any tr\ble ( ?is k9d has ev] be5 exp]i5c$ at ,brem5 or at ,altona2 & ! objection to ?is sy/em is p]haps n well f\nd$ :]e ! managem5t is c>eful & consci5ti\s4 ,! fact t an unscrupul\s att5dant c make ! connection at any "t to help out a defici5cy ( supply1 or simply ?r\gh c>elessness1 is c]ta9ly objectionable4 ,= ! treatm5t ( riv]-wat]s & lake-wat]s conta9+ only a small quantity ( s$im5t1 & :]e ! removal ( bact]ia or disease-produc+ qualities is ! mo/ important object ( filtration1 s& filt]s c be us$4 ,:]e ! riv]s are subject to floods & mod]ate am\nts ( muddy wat]1 s$im5tation-bas9s or /orage res]voirs = raw wat] w (t5 be f\nd advantage\s4 ,= ! treatm5t ( extremely muddy wat]s1 & wat]s :i* are cont9u\sly muddy = long p]iods ( "t1 & = ! removal ( color f v highly color$ wat]s1 res\rce mu/ be _h to coagulants4 ,! coagulants :i* are necess>y 9 ea* special case & :i* c be us$ )\t injury to ! wat] mu/ be det]m9$ by mo/ c>eful inve/igation ( ! raw wat]4 ,= ! filtration ( ^! wat]s aft] coagulation ei!r s& or me*anical filt]s c be employ$4 ,z ! pr9cipal "w 9 ?is case is done by ! coagulant1 ! k9d ( filtration employ$ is ( less consequ5ce ?an :]e filtration alone is reli$ ^u1 & ! *eape/ =m ( filt] w naturally be employ$4 ,"u pres5t conditions me*anical filt]s w usually be *eap] ?an s& filt]s = use 9 ?is way2 b :]e wat]s1 9 addition to ! mud1 c>ry bact]ia 9 su* l>ge numb]s z to make high bact]ial effici5cy a matt] ( importance1 s& filt]s may be select$1 z ! bact]ial effici5cy obta9$ ) !m is n dep5d5t ^u ! use ( coagulant2 & is !re=e less subject to int]ruptions f ! failure to apply coagulant 9 ! "r proportion4 ,me*anical filt]s h also be5 us$ = ! treatm5t ( comp>atively cle> wat]s :]e bact]ial effici5cy 0 ! pr9cipal object ( filtration4 ,= ?is purpose ! effici5cies obta9$ ) !m are usually inf]ior to ^? obta9$ ) s& filt]s1 :ile ! co/ ( coagulants is s great z to make _! use (t5 m exp5sive ?an t ( s& filt]s4 ,9 ! case ( _m /reams :i* are comp>atively cle> = a "p ( ! ye>1 b occasionally are q turbid1 ! use ( s& filt]s has ?is advantage1 t ! use ( coagulants c be /opp$ & ! co/ ( op]ation r$uc$ :5ev] ! wat] is cle> en\gh to all[ ( satisfactory treatm5t by !m2 & t coagulant c be employ$ on ^? days :5 o!rwise insuffici5t cl>ification w\ld be obta9$4 ,9 ?is case ! high bact]ial effici5cy is secur$ at all times1 :ile ! co/ ( coagulant is sav$ dur+ ! great] "p ( ! "t4 ,9 su* cases1 also1 ! prelim9>y process ( s$im5tation & /orage %\ld be develop$ z f> z possible4 ,! application ( o!r processes ( filtration to special problems are n suffici5tly well und]/ood to all[ g5]al discussion1 & mu/ be tak5 up sep>ately ) ref]5ce to ! requirem5ts ( ea* special situation4 ,,co/ ,,( ,,filtration4 ,! co/ ( filtration ( wat] dep5ds ^u ! "* ( ! raw wat]1 ^u ! nature ( ! plant employ$1 ^u its size1 & ^u ! skill & economy ( manipulation4 ,^! conditions affect ! co/ to su* an ext5t z to make any accurate g5]al e/imate q impossible4 ,nev]!less a little consid]ation ( ! subject1 al?\gh n lead+ to exact results1 may be helpful z furni%+ a r\gh idea ( ! probable co/ be=e e/imates = local conditions are made4 ,op5 s& filt]s1 ) masonry walls1 ) reasonably favorable conditions ( con/ruction1 & n too small 9 area1 h av]ag$ to co/ 9 ! ,unit$ ,/ates )9 ! la/ few ye>s p]haps ab\t ?irty ?\s& doll>s p] acre4 ,! relative co/ ( small plants is some:at great]1 & ) embankm5ts in/ead ( masonry walls1 ! co/ is some:at r$uc$4 ,! co/ is less :]e natural deposits ( s& c be made use ( practically 9 _! orig9al condition1 & is increas$ :]e ! filt]+ mat]ials h to be transport$ by rail = long di/ances1 or :]e ! sites are difficult to build ^u4 ,cov]$ filt]s co/ ab\t a half m ?an op5 filt]s4 ,me*anical filt]s at curr5t prices co/ ab\t #bj p] squ>e foot ( filt]+ area1 to :i* mu/ be add$ ! co/ ( f\ndations & build+s1 :i* p]haps av]age to co/ half z mu* m1 b are dep5d5t ^u local conditions & ! "* ( ! build+s4 ,to ^! figures mu/ be add$ ! co/s ( pumps1 res]voirs1 s$im5tation-bas9s1 & pipe-connections1 :i* are (t5 great] ?an ! co/s ( ! filt]s1 b :i* diff] s widely 9 diff]5t cases z to make any g5]al e/imate impossible4 ,filt]s mu/ be provid$ suffici5t to meet ! maximum & n ! av]age consumption4 ,! excess ( maximum ov] av]age requirem5ts v>ies greatly 9 diff]5t cities1 & dep5ds l>gely ^u res]voir capacities & arrangem5ts4 ,z a result ( a consid]able numb] ( e/imates made by ! au?or = av]age ,am]ican conditions1 ! co/ ( in/all+ filt]s may be tak5 v r\ghly z five doll>s p] inhabitant1 b ! am\nts diff] widely 9 v>i\s cases4 ,! co/ ( op]ation ( s& filt]s 9 ,engl& probably av]ages ab\t "o doll> p] million gallons ( wat] filt]$4 ,! foll[+ table %[s ! co/s ( op]ation ( ! filt]s ( ! sev5 ,london companies = fifte5 ye>s1 compil$ 9 ! (fice ( ,mr4 ,w4 ,b4 ,bryan1 ,*ief ,eng9e] ( ! ,ea/ ,london ,wat] ,company4 ,! results h be5 comput$ to doll>s p] million ,u4 ,s4 gallons1 & include ! co/ ( all labor1 s&1 & supplies = ! filt]s1 b d n include any pump+ or int]e/ co/s4 ,,co/ ,,( ,,filtration1 ,,london ,,wat] ,,companies4 7,comput$ f data furni%$ ,wm4 ,b4 ,bryan1 ,c4,e41 ,ea/ ,london ,wat] ,works47 ,doll>s p] ,million ,u4 ,s4 ,gallons4 ---------------------------------------- --------------------------- ,ea/ ,gr& ,new ,s\?w>k ,we/ ,*elsea,london,junction,lambe?,riv] ,middlesex,av]age4 ,co4 ,co4 ,co4 ,co4 ,co4 ,vauxhall ,co4 ,co4 ---------------------------------------- --------------------------- #ahhj-a #a4af #a4af #a4jj #j4hc #a4cd #a4af #a4fg #a4ai #ahha-b #a4ai #a4ci #j4ie #j4hb #a4ae #a4cg #a4ed #a4bj #ahhb-c #a4aj #a4bc #a4ci #j4if #a4dj #a4dg #a4gd #a4cc #ahhc-d #a4jj #a4jf #a4gc #j4ib #a4aa #a4fb #a4fg #a4cj #ahhd-e #a4jf #a4jf #a4hb #j4ij #a4jb #a4dj #a4cj #a4bb #ahhe-f #a4ae #a4af #a4ce #j4ij #a4jj #a4ae #a4jg #a4aa #ahhf-g #j4hj #j4if #a4ci #j4hg #j4ih #a4dc #a4gj #a4af #ahhg-h #a4jg #a4bb #a4gd #j4ij #j4ib #a4bh #a4jj #a4af #ahhh-i #j4hc #a4bh #a4ee #j4ie #j4ih #a4eb #j4hc #a4ac #ahhi-ij #j4ff #a4ej #a4bb #j4hh #j4ij #a4gj #c4ef #a4di #ahij-a #j4gb #a4db #a4cb #j4he #a4jb #a4af #a4jj #a4jg #ahia-b #j4ge #a4ed #a4bc #a4jj #j4ib #a4ae #j4if #a4jh #ahib-c #j4fg #a4db #a4cj #a4ai #a4af #a4bf #a4db #a4bj #ahic-d #a4ae #b4fc #b4jj #a4df #a4dc #a4eb #j4ie #a4ei #ahid-e #j4fj #a4fh #a4fg #b4ec #a4jc #a4cd #j4if #a4dj ---------------------------------------- --------------------------- ,av]age #j4ic #a4ch #a4dd #a4jf #a4ji #a4cg #a4dc #a4bd ---------------------------------------- --------------------------- ,av]age ( sev5 companies = #ae ye>s1 #a4bd p] million gallons4 ,v>iations f ye> to ye> are caus$ by diff]5ces 9 ! am\nts ( ice1 & 9 ! quantities ( new s& pur*as$4 ,wages av]age ab\t #a4jj p] day4 ,at ,liv]pool = #ahif ! co/ 0 #a4jh p] million ,u4 ,s4 gallons4 ,9 ,g]many1 ) m turbid riv]-wat]s1 ! co/s ( op]ation are some:at high] ?an ! ,london figures1 :ile at ,zri*1 :]e ! wat] is v cle>1 !y are l[]4 ,9 ! ,unit$ ,/ates ! data reg>d+ ! co/ ( op]ation ( s& filt]s are less complete4 ,at ,mt4 ,v]non1 ,n4 ,y41 ) res]voir-wat]1 ! co/ has av]ag$ ab\t two doll>s p] million gallons4 ,at ,p\ghkeepsie1 ,n4 ,y41 ) ! ,hudson ,riv] wat]1 :i* is occasionally mod]ately turbid1 ! co/ = tw5ty ye>s has av]ag$ ?ree doll>s p] million gallons4 ,?is co/ includes ! co/ ( h&l+ ice1 & z ! av]age w9t] temp]ature is consid]ably bel[ t sugge/$ = op5 filt]s1 ! exp5se ( ?is "w has be5 consid]able1 & has increas$ consid]ably ! total co/ ( op]ation4 ,at ,f> ,rockaway1 ,l4 ,i41 & ,r$ ,bank ,n4 ,j41 = iron-removal plants1 ! co/ ( op]ation has h>dly be5 appreciable4 ,! plants are bo? close to ! pump+-/ations1 & x has be5 possible to op]ate !m ) ! labor necess>ily engag$ at ! pump+-/ation )\t additional co/1 except a v small am\nt ( labor on ! s& at ,f> ,rockaway4 ,no computation has be5 made 9 ^! cases ( ! additional coal requir$ = pump+4 ,at ,lawr5ce1 ,mass41 ! co/ ( op]ation = #ahie 0 z foll[s3 ,co/ ( scrap+ & replac+ s& #c1dfg ,co/ ( c>e ( ice #b1ijc ------ ,total co/ ( op]ation #f1cgj ,wat] filt]$1 millions ( gallons #a1jig ,co/ p] million gallons #e4hj ,! co/ ( c>e ( ice has be5 excessive at ,lawr5ce1 & x has be5 repeat$ly recomm5d$ to cov] ! filt] to avoid ?is exp5se4 ,! co/ ( h&l+ s& has be5 v greatly increas$1 because ! filt] is built 9 "o b$1 & all "w ^u x has to be done dur+ ! comp>atively %ort int]vals :5 ! filt] is n 9 use1 an arrangem5t :i* is n at all economical 9 ! use ( labor4 ,! co/ ( op]ation is ?us mu* high] ?an x w\ld be _h ! plant be5 con/ruct$ 9 sev]al units1 ea* ( :i* c\ld be disconnect$ = ! purpose ( be+ clean$ 9 ! ord9>y mann]4 ,z aga9/ ?is ! fir/ co/ ( con/ruction 0 extremely l[1 & ! sav+ 9 int]e/ *>ges %\ld be cr$it$ aga9/ ! increas$ co/ ( labor 9 clean+4 ,! co/ ( op]at+ filt]s at ,a%l&1 ,wis41 has be5 e/imat$ by ,mr4 ,william ,:eel] at #b4bf p] million gallons4 ,?is e/imate is bas$ ^u ! p]=mance = ! fir/ ye> t !y 7 9 s]vice4 ,9 ! op]ation ( me*anical filt]s "o ( ! l>ge/ items ( exp5se is = ! coagulant1 & ! am\nt ( ?is dep5ds entirely ^u ! "* ( ! raw wat] & ! ?or\ghness ( ! treatm5t requir$4 ,! data reg>d+ ! o!r or g5]al co/s ( op]ation ( me*anical filt]s are few & unsatisfactory4 ,i rec5tly made "s e/imates ( co/ ( cl>ify+ wat]s ( v>i\s degrees ( turbidity by s& & me*anical filt]s4 ,^! e/imates 7 made = a special set ( conditions1 & ,i d n "k t !y w fit o!rs1 b !y h at lea/ a sugge/ive value4 ,! results %[n by ,fig4 #bf include only ! co/ ( op]ation1 & n int]e/ & depreciation *>ges4 ,^! figures1 :5 us$ = plants 9 connection ) :i* prelim9>y treatm5ts are us$1 %\ld be appli$ to ! turbidity ( ! wat] z appli$ to ! filt]s1 & n to ! raw wat]1 & ! co/s ( ! prelim9>y processes %\ld be add$4 ,) s& filt]s ! frequ5cy ( scrap+ is ne>ly proportional to ! turbidity2 & z scrap+ repres5ts mo/ ( ! exp5ses1 ! co/s ( op]ation are proportional to ! turbidity1 except ! g5]al co/s1 & ! co/ ( ! am\nt ( scrap+1 :i* is necess>y ) ev5 ! cle>e/ wat]s4 ,) me*anical filt]s ! am\nt ( sulphate ( alum9a requir$ = cl>ification increases ) ! turbidity1 & mo/ ( ! co/s ( op]ation increase 9 ! same ratio4 ,! diagram %[s ! am\nt ( sulphate ( alum9a 9 gra9s p] gallon necess>y = cl>ification ) diff]5t degrees ( turbidity4 ,) ! cle>e/ wat]s ! co/s ( op]ation on ! two sy/ems are sub/antially equal4 ,) muddy wat]s1 ! exp5se ( op]at+ s& filt]s increases m rapidly ?an ! exp5se ( op]at+ me*anical filt]s4 ,illu/ration3 ,,turbidity ,,fig4 #bf4--;,,co/ ,,( ,,op]ation ,,( ,,filt]s4 ,!re is ano!r elem5t :i* (t5 comes into ! comp>ison1 namely1 ! "q ( purification f ! effects ( sewage-pollution4 ,ne>ly all riv]s us$ = public wat]-supplies receive m or less sewage1 & 9 filt]+ su* wat]s x is reg>d$ z necess>y to remove z completely z possible ! bact]ia4 ,! quantities ( sulphate ( alum9a requir$ = ! cl>ification ( ! lea/ turbid wat]s are n suffici5t to give ev5 tol]ably good bact]ial effici5cies4 ,to secure a reasonably complete removal ( bact]ia ) me*anical filt]s1 ! use ( a consid]able quantity ( sulphate ( alum9a is requir$4 ,let u assume t #ih p] c5t bact]ial effici5cy is requir$1 & t to produce ?is effici5cy x is necess>y to use "o gra9 ( coagulant to ! gallon4 ,) wat] requir+ less ?an ?is quantity ( coagulant = cl>ification ?is quantity mu/ nev]!less be us$1 & ! co/s w be controll$ by x1 & n by ! l[] quantities :i* w\ld suffice = cl>ification1 b w\ld n give ! requir$ bact]ial effici5cy4 ,i h add$ ?is l9e to ! diagram1 & ?is1 comb9$ ) ! upp] portion ( ! l9e %[+ co/ ( cl>ification1 repres5ts ! co/ ( treat+ wat]s ) me*anical filt]s1 :]e bo? bact]ial effici5cy & cl>ification are requir$4 ,?is l9e1 consid]$ z a :ole1 increases mu* less rapidly ) increas+ turbidity ?an does ! correspond+ l9e = s& filt]s1 & ! two l9es cross ea* o!r4 ,) ! cle>e/ wat]s s& filt]s are *eap] ?an me*anical filt]s1 & = ! muddie/ wat]s !y are m exp5sive4 ,x does n appe> f ! diagram1 b x is also true 9 ea* case1 t ! *eap] sy/em is also ! m effici5t4 ,s& filt]s are m effici5t 9 remov+ bact]ia f cle> wat]s ?an are me*anical filt]s1 & me*anical filt]s are m effici5t 9 cl>ify+ v muddy wat]s ?an are s& filt]s4 ,,:at ,,wat]s ,,require ,,filtration8 ,f ! nature ( ! case a satisfactory g5]al answ] to ?is "q _c be giv51 b a few sugge/ions may be useful4 ,9 ! fir/ place1 gr\nd-wat]s obvi\sly d n require filtration3 !y h already 9 mo/ cases be5 ?or\ghly filt]$ 9 ! gr\nd ?r\gh :i* !y h pass$1 & 9 ! exceptional cases1 z1 = in/ance1 an artesian well draw+ wat] ?r\gh fissures 9 a l$ge f a pollut$ orig91 a new supply w g5]ally be *os5 r ?an to attempt to improve s d\btful a raw mat]ial4 ,riv]-wat]s %\ld be filt]$4 ,x _c be ass]t$ t !re are no riv]s 9 m\nta9\s di/ricts 9 :i* ! wat] is at once cle> & free f pollution1 & suitable 9 its natural /ate = wat]-supply2 b if s1 !y are n common1 lea/ ( all 9 ! regions :]e wat]-supplies are usually requir$4 ,! use ( riv]-wat]s 9 _! natural /ate or aft] s$im5tation only1 drawn f su* riv]s z ! ,m]rimac1 ,hudson1 ,potomac1 ,delaw>e1 ,s*uylkill1 ,ohio1 & ,mississippi1 is a fil?y z well z an unheal?y practice1 :i* ought to be ab&on$4 ,! "q is m difficult 9 ! case ( supplies drawn f lakes or /orage res]voirs4 ,_m su* supplies are grossly pollut$ & %\ld be ei!r ab&on$ or filt]$4 ,o!rs are subject to alg gr[?s1 or are muddy1 & w\ld be mu* improv$ by filtration4 ,/ill o!rs are drawn ei!r f unpollut$ wat]-%$s1 or ! pollution is s greatly dilut$ & r$uc$ by /orage t no kn[n disadvantage results f _! use4 ,9 measur+ ! effects ( ! pollution ( wat]-supplies1 ! typhoid-fev] dea?-rate is a mo/ important aid4 ,n t typhoid fev] is ! sole evil result+ f pollut$ wat]1 b because x is also a v useful index ( o!r evils = :i* correspond+ /ati/ics _c be obta9$1 z1 = in/ance1 ! causation ( di>rhal diseases or ! dang] f invasion by *ol]a4 ,i ?9k we %all n g f> wrong at ! />t to conf9e our att5tion to ^? cities :]e !re are ov] #be dea?s f typhoid fev] p] #ajj1jjj ( population4 ,?is w at once ?r[ out ( consid]ation a l>ge numb] ( relatively good supplies1 includ+ ^? ( ,new ,york & ,brooklyn4 ,x is n my idea t none ( ^! supplies cause disease4 ,_m ( !m1 z = in/ance t ( ,new ,york1 are kn[n to receive sewage1 & x is an int]e/+ "q wor?y ( mo/ c>eful /udy :e!r !re are cases ( sickness result+ f ?is pollution4 ,! po9t t ,i wi% to make n[ is simply t 9 ^? cases ! dea?-rate itself is evid5ce t1 ) exi/+ conditions ( dilution & /orage1 ! result+ damage ( :i* we h k is n great en\gh to ju/ify ! exp5se involv$ by filtration4 ,9 ?is connection x %\ld n be =gott5 t1 especially ) v small wat]%$s1 !re may be a dang] z di/9ct f pres5t damage :i* requires consid]ation4 ,?us a s+le h\se or gr\ps ( h\ses dra9+ into a supply may n appreciably affect x = ye>s1 until an outbreak ( fev] on ! wat]-%$ results 9 infect+ ! wat] ) ! g]ms ( disease & 9 an epidemic 9 ! city bel[4 ,?is dang] decreases ) increas+ size ( ! wat]-%$ & volume ( ! wat] ) :i* any su* pollution w\ld be mix$1 & also ) ! population dra9+ into ! wat]1 z !re is a probability t ! am\nt ( infection cont9ually add$ f a consid]able t[n w n be subject to z viol5t fluctuation z t f only a few h\ses4 ,?us 9 ,plym\?1 ,pa41 9 #ahhe1 !re 7 #aajd cases ( typhoid fev] & #aad dea?s among a population ( #hjjj1 z ! result ( ! dis*>ge ( ! dejecta f a s+le typhoid pati5t into ! wat] ( a relatively small imp\nd+ res]voir4 ,! co/ ( ?is epidemic 0 calculat$ ) unusual c>e4 ,! c>e ( ! sick co/ 9 ca% #fg1ajj4ag1 & ! loss ( wages = ^? :o recov]$ am\nt$ to #cj1jbj4jh4 ,! #aad p]sons :o di$ 7 e>n+ be=e _! sickness at ! rate ( #ah1dai4eb annually4 ,su* an outbreak w\ld h>dly be possible ) ! ,croton wat]-%$ ( ! ,new ,york wat]-supply1 on acc\nt ( ! great dilution & delay 9 ! res]voirs1 b x mu/ be gu>d$ aga9/ 9 small supplies4 ,( ! cities hav+ m ?an #be dea?s p] #ajj1jjj f typhoid fev]1 "s w no d\bt be f\nd :]e milk epidemics or o!r special circum/ances 7 ! cause2 b ,i believe 9 a majority ( !m1 & 9 ne>ly all cases :]e ! rate is ye> aft] ye> consid]ably above t figure1 ! cause w be f\nd 9 ! wat]-supply4 ,inve/igation %\ld be made ( ?is po9t2 & if ! wat] is n at fault1 ! responsibility %\ld be locat$4 ,if ! wat] is guilty1 x %\ld be ei!r purifi$ or a new supply obta9$4 ,,*apt] ,,xiv4 ,,wat]-,,supply ,,& ,,disease--,,conclusions4 ,"o ( ! mo/ *>act]i/ic & uni=m results ( ! direct pollution ( public wat]-supplies is ! typhoid fev] :i* results among ! us]s ( ! wat]4 ,9 ! ,engli% & ,g]man cities ) almo/ uni=mly good dr9k+-wat]1 typhoid fev] is already ne>ly ext]m9at$1 & is decreas+ f ye> to ye>4 ,am]ican cities hav+ unpollut$ wat]-supplies h comp>atively few dea?s f ?is cause1 al?\gh ! figures nev] g s l[ z 9 ,europe1 p]haps on acc\nt ( ! fre% cases :i* are always com+ 9 f less heal?y neighborhoods 9 ev]-mov+ ,am]ican communities4 ,9 o!r ,am]ican cities ! dea?-rates f typhoid fev] are _m times :at !y ought to be & :at !y actually are 9 o!r cities1 & ! rates 9 v>i\s places1 & 9 ! same place at diff]5t times1 be> 9 g5]al a close relation to ! ext5t ( ! pollution ( ! dr9k+-wat]4 ,! p[] ( suitable filtration to protect a city f typhoid fev] is amply %[n by ! v l[ dea?-rates f ?is cause 9 ,london1 ,b]l91 ,breslau1 & l>ge numb]s ( o!r cities draw+ _! raw wat] f s\rces m contam9at$ ?an ^? ( any b ! v wor/ ,am]ican supplies1 & by ! m>k$ & great r$uctions 9 ! typhoid-fev] dea? rates :i* h foll[$ at once ! in/allation ( filt]s at ,zri*1 ,switz]l&2 ,hamburg1 ,g]many2 ,lawr5ce1 ,mass41 & o!r places4 ,! foll[+ is a li/ ( ! cities ( #ej1jjj inhabitants & upw>d 9 ! ,unit$ ,/ates1 ) dea?s f typhoid fev] & ! s\rces ( _! wat]-supplies4 ,! dea?s & populations are f ! ,u4 ,s4 ,c5sus = #ahij2 ! s\rces ( ! wat]-supplies1 f ! ,am]ican ,wat]-,works ,manual = ! same ye>4 ,f\r cities ( ?is size--,gr& ,rapids1 ,l9coln1 ,/4 ,joseph1 & ,des ,mo9es--are n includ$ 9 ! c5sus returns ( mortality4 ,two cities ) less ?an #ej1jjj inhabitants ) exceptionally high dea?-rates h be5 includ$1 & at ! foot ( ! li/ are giv5 correspond+ data = "s l>ge ,european cities = #ahic4 ,,typhoid ,,fev] ,,dea?-,,rates ,,& ,,wat]-,,supplies ,,( ,,cities4 ---------------------------------------- --------------------------- ,dea?s f ,typhoid ,fev]4 ,city4 ,population4------------- ,wat]-supply4 ,p] ,total4#ajj1jjj liv+4 ---------------------------------------- -------------------------- ,birm+ham #bf1agh #fi #bfd ,five ,mile ,creek #a4 ,d5v] #ajf1gac #bcb #bag ,nor? ,platte ,riv] & wells #b4 ,allegh5y #aje1bhg #aib #ahb ,allegh5y ,riv] #c4 ,camd5 #eh1cac #gg #acb ,delaw>e ,riv] #d4 ,pittsburg #bch1fag #cjd #abg ,allegh5y & ,monongahela riv]s ,lawr5ce #dd1fed #ed #aba ,m]rimac ,riv] #e4 ,new>k #aha1hcj #aha #ajj ,passaic ,riv] #f4 ,*>le/on #ed1iee #ed #ih ,artesian wells yield+ #a1fjj1jjj gallons daily #g4 ,wa%+ton #bcj1cib #bjj #hg ,potomac ,riv] #h4 ,l[ell #gg1fif #fd #hb ,m]rimac ,riv] #i4 ,j]sey ,city #afc1jjc #acd #hb ,passaic ,riv] #aj4 ,l\isville #afa1abi #abb #gf ,ohio ,riv] #aa4 ,philadelphia #a1jdf1ifd #ggj #gd ,delaw>e & ,s*uylkill riv]s #ab4 ,*icago #a1jii1hej #gid #gb ,lake ,mi*igan #ac4 ,atlanta #fe1ecc #dg #gb ,s\? ,riv] #ad4 ,albany #id1ibc #fg #ga ,hudson ,riv] #ae4 ,wilm+ton #fa1dca #dc #gj ,br&yw9e ,creek #af4 ,/4 ,paul #acc1aef #ib #fi ,lakes #ag4 ,troy #fj1ief #db #fi ,hudson ,riv] & imp\nd+ res]voirs #ah4 ,los ,angeles #ej1cie #cd #fg ,los ,angeles ,riv] & spr+s #ai4 ,na%ville #gf1afh #di #fd ,cumb]l& ,riv] #bj4 ,clevel& #bfa1cec #afd #fc ,lake ,erie #ba4 ,ri*mond #ha1chh #ej #fa ,james ,riv] #bb4 ,h>t=d #ec1bcj #cb #fj ,connecticut ,riv] & imp\nd+ res]voir #bc4 ,fall ,riv] #gd1cih #dd #ei ,watupa ,lake #bd4 ,m9neapolis #afd1gch #id #eg ,mississippi ,riv] #be4 ,san ,francisco #bih1iig #aff #ef ,lobus ,creek1 ,lake ,m]c$1 & m\nta9 /reams #bf4 ,indianapolis #aje1dcf #eg #ed ,:ite ,riv] #bg4 ,c9c9nati #bif1ijh #aea #ea ,ohio ,riv] #bh4 ,memphis #fd1die #cc #ea ,artesian ,wells #bi4 ,read+ #eh1ffa #bi #di ,maid5 ,creek & ,spr+s #cj4 ,baltimore #dcd1dci #bjb #dg ,imp\nd+ res]voir #ca4 ,omaha #adj1deb #fc #de ,miss\ri ,riv] #cb4 ,columbus #hh1aej #ch #dc ,surface-wat] & wells #cc4 ,provid5ce #acb1adf #ec #dj ,pawtuxet ,riv] #cd4 ,kansas ,city #acb1gaf #ec #dj ,miss\ri ,riv] #ce4 ,ro*e/] #acc1hif #ec #ci ,hemlock & ,c&ice lakes #cf4 ,evansville #ej1gef #bj #ci ,ohio ,riv] #cg4 ,bo/on #ddh1dgg #agd #ci ,imp\nd+ res]voirs #ch4 ,tol$o #ha1dcd #bi #cf ,maumee ,riv] #ci4 ,cambridge #gj1jbh #bd #cd ,imp\nd+ res]voir #dj4 ,/4 ,l\is #dea1ggj #ade #cb ,mississippi ,riv] #da4 ,scranton #ge1bae #bd #cb ,imp\nd+ res]voir #db4 ,buffalo #bee1ffd #hj #ca ,niag>a ,riv] #dc4 ,milwaukee #bjd1dfh #fa #cj ,lake ,mi*igan #dd4 ,new ,hav5 #ha1bih #bb #bg ,imp\nd+ res]voir #de4 ,worce/] #hd1fee #bb #bf ,imp\nd+ res]voir #df4 ,pat]son #gh1cdg #bj #bf ,passaic ,riv] 7high] up7 #dg4 ,dayton #fa1bbj #ae #be ,wells #dh4 ,brooklyn #hjf1cdc #aid #bd ,wells1 ponds1 & imp\nd+ res]voirs #di4 ,new ,york #a1eae1cja #cdh #bc ,imp\nd+ res]voir #ej4 ,syracuse #hh1adc #ah #bj ,imp\nd+ res]voir & spr+s #ea4 ,new ,orleans #bdb1jci #de #ai ,mississippi ,riv] #eb4 ,detroit #bje1hgf #dj #ai ,detroit ,riv] #ec4 ,lynn #ee1gbg #i #af ,imp\nd+ res]voir #ed4 ,tr5ton #eg1deh #i #af ,delaw>e ,riv] ,london #d1cjf1daa #gai #ag ,filt]$ ,?ames & ,lea riv]s & #a_/d f wells ,glasg[ #ffg1hhc #ach #bj ,lo* ,katr9e ,p>is #b1dbd1gje #fji #be ,spr+ wat] ,am/]dam #dcg1hib #fi #af ,filt]$ dune-wat] ,rott]dam #bbb1bcc #ab #e ,filt]$ ,maas ,riv] ,hague #afi1hbh #c #b ,filt]$ dune-wat] ,b]l9 #a1gad1ich #afa #i ,filt]$ ,havel & ,spree riv]s ,hamburg #fcd1hgh #aae #ah ,filt]$ ,elbe ,riv] ,breslau #cec1eea #cg #aa ,filt]$ ,od] ,riv] ,dresd5 #cjh1icj #ad #e ,gr\nd-wat] ,vi5na #a1dce1ica #ajd #g ,spr+-wat] ---------------------------------------- -------------------------- ,any full discussion ( ^! data w\ld require intimate acqua9tances ) ! v>i\s local conditions :i* x is impossible to take up 9 detail "h1 b "s ( ! lead+ facts _c fail to be in/ructive4 ,ea* ( ! places hav+ ov] #ajj dea?s p] #ajj1jjj f typhoid fev] us$ unfilt]$ riv]-wat]4 ,l[] 9 ! li/1 b /ill v high1 ,*>le/on1 said to h be5 suppli$ only f artesian wells1 _h an excessive rate2 b ! report$ wat]-consumption is s l[ z to sugge/ t private wells or o!r means ( supply 7 9 common use4 ,*icago & ,clevel& bo? drew _! wat] f lakes :]e !y 7 contam9at$ by _! own sewage4 ,/4 ,paul's supply came f ponds1 ( :i* ,i d n "k ! "*4 ,) ^! exceptions all ( ! #bb cities ) ov] #ej1jjj inhabitants1 at ! head ( ! li/1 _h unfilt]$ riv]-wat]4 ,! cities suppli$ f imp\nd+ res]voirs z a rule _h l[] dea? rates & are at ! l[] end ( ! li/1 toge!r ) "s cities tak+ _! wat] supplies f riv]s or lakes at po9ts :]e !y 7 subject to only small] or m remote infection4 ,only ?ree ( ! ,am]ican cities 9 ! li/ 7 report$ z be+ suppli$ entirely ) gr\nd-wat]4 ,x is n my purpose to make too close comp>isons betwe5 ! v>i\s cities on ! li/2 "s ( !m may h be5 influ5c$ by unusual local conditions 9 #ahij4 ,o!rs h 9 "o way or ano!r improv$ _! wat]-supplies s9ce t date1 & !re are sev]al cities 9 :i* ,i "k ! pres5t typhoid-fev] dea?-rates to be mat]ially l[] ?an ^? ( #ahij giv5 9 ! table4 ,on ! o!r h&1 x is equally true t a numb] ( cities1 includ+ "s ( ! l>g] ones1 h s9ce _h sev]e epidemics ( typhoid fev] :i* h giv5 v mu* high] rates ?an ^? = #ahij4 ,^! fluctuations w\ld *ange ! ord] ( cities 9 ! li/ f ye> to ye>2 !y w\ld n *ange ! g5]al facts1 :i* are z true to-day z !y 7 9 #ahij4 ,ne>ly all ( ! great cities ( ! ,unit$ ,/ates are suppli$ ) unfilt]$ surface-wat]s1 & a great majority ( ! wat]s are tak5 f riv]s & lakes at po9ts :]e !y are pollut$ by sewage4 ,! dea?-rates f typhoid fev] 9 ^? cities1 :e!r !y are comp>$ ) bett] suppli$ cities ( ?is c\ntry1 or ) ,european cities1 are enorm\sly high4 ,su* rates 7 =m]ly common 9 ,european cities1 b !y h disappe>$ ) bett] sanit>y conditions4 ,! introduction ( filt]s has (t5 work$ m>vell\s *anges 9 ,europe1 & 9 ,lawr5ce ! improvem5t 9 ! city's heal? ) filt]$ wat] 0 prompt & unque/ionable4 ,!re is e reason to believe t ! g5]al introduction ( bett] wat] 9 ,am]ican cities w "w correspond+ revolutions2 & look+ at x f a m]ely money /&po9t1 ! value ( ! lives & ! sav+ ( ! exp5ses ( sickness w pay h&somely :5 comp>$ ) ! co/ ( good wat]4 ,! reasons = believ+ t *ol]a is caus$ by pollut$ wat] are entirely simil> to ^? 9 ! case ( typhoid fev]4 ,x 0 no accid5t t ! epidemic ( *ol]a :i* caus$ ! dea? ( #cdjj p]sons foll[$ ! tempor>y supply ( unfilt]$ wat] by ! ,ea/ ,london ,wat] ,company 9 #ahff1 :ile ! re/ ( ,london rema9$ ne>ly free1 or t ! only s]i\s outbreak ( *ol]a 9 ,we/]n ,europe 9 #ahib 0 at ,hamburg1 :i* 0 also ! only city 9 ,g]many :i* us$ raw riv]-wat]4 ,?is latt] caus$ ! sickness ( #bj1jjj & ! dea? ( ov] #hjjj p )9 a mon?1 & an am\nt ( suff]+ & f9ancial loss1 ) ! panics :i* result$1 t _c be e/imat$1 b t exce$$ _m times ! co/ ( ! filt]s :i* h s9ce be5 put 9 op]ation4 ,hamburg _h sev]al times be=e suff]$ sev]ely f *ol]a1 & ! removal ( ?is dang] 0 a lead+1 al?\gh n ! sole1 motive = ! con/ruction ( filt]s4 ,h[ little cities suppli$ ) pure wat] h to dread f *ol]a is %[n by ! exp]i5ce ( ,altona & o!r suburbs ( ,hamburg ) good wat]-supplies1 :i* _h b few cases ( *ol]a n directly br\ght f ! latt] place1 & by ! exp]i5ce ( ,engl&1 :i* ma9ta9$ un9t]rupt$ comm]cial int]c\rse ) ! plague-/rick5 city1 absolutely )\t qu>ant9e1 &1 not)/&+ a few cases :i* 7 directly import$1 ! disease ga9$ no foo?old 9 ,engl&4 ,i d n "k ( a s+le mod]n ,european in/ance :]e a city ) a good wat]-supply n directly infect$ by sewage has suff]$ sev]ely f *ol]a4 ,i %all leave to o!rs m famili> ) ! facts ! discussion ( :at happ5$ be=e ! introduction ( mod]n sanit>y me?ods1 z well z ( ! pres5t conditions 9 ,asia2 al?\gh ,i believe t 9 ^! cases also !re is pl5ty ( evid5ce z to ! "p wat] plays 9 ! spread ( ! disease4 ,a consid]able proportion ( ! wat]-supplies ( ! cities ( ! ,unit$ ,/ates are s pollut$ t 9 case *ol]a %\ld ga9 a foo?old ^u our %ores we h no gr\nd = hop+ = ! favorable exp]i5ce ( ! ,engli% cities r ?an ! plague ( ,hamburg 9 #ahib4 ,! fces f a man conta9 on an av]age p]haps #a1jjj1jjj1jjj bact]ia p] gram1#dg mo/ ( !m be+ ! normal bacilli ( ! inte/9es1 ,bacillus coli communis4 ,assum+ t a man dis*>ges #bjj grams or ab\t #g ounces ( fces daily1 ?is w\ld give #bjj1jjj1jjj1jjj bact]ia dis*>g$ daily p] p]son4 ,! numb] ( bact]ia actually f\nd 9 ,am]ican sewage is usually high]1 (t5 d\ble ?is numb] p] p]son2 b !re are o!r s\rces ( bact]ia 9 sewage1 & 9 addition gr[?s or ! rev]se may take place 9 ! sew]s1 accord+ to circum/ances4 ,?is numb] ( bact]ia 9 sewage is s enorm\sly l>ge t ! addition ( ! sewage f a village or city to ev5 a l>ge riv] is capable ( affect+ its entire bact]ial composition4 ,?us tak+ ! population ( ,l[ell 9 #ahib at #he1jjj1 & ! av]age daily fl[ ( ! ,m]rimac at #fjjj cubic feet p] second1 & assum+ t #bjj1jjj1jjj1jjj bact]ia are dis*>g$ daily 9 ! sewage f ea* p]son1 !y w\ld increase ! numb] 9 ! riv] by #aafj p] cubic c5timet]1 or ab\t #cjj1jjj 9 an ord9>y glass ( wat]4 ,! av]age numb] f\nd 9 ! wat] eight miles bel[1 at ! intake ( ! ,lawr5ce wat]-works1 0 m ?an six times z great z ?is1 due 9 "p to ! sewage ( o!r cities high] up4 ,!re is e reason to believe t ! bulk ( ^! bact]ia 7 h>mless to ! p ( ,lawr5ce1 :o drank !m2 b "s ( !m 7 n4 ,fces ( p suff]+ f typhoid fev] conta9 ! g]ms ( t disease4 ,:at proportion ( ! total numb] ( bact]ia 9 su* fces are injuri\s is n kn[n2 b assum+ t "o f\r? only ( ! total numb] are typhoid g]ms1 & suppos+ ! fces ( "o man to be ev5ly mix$ ) ! :ole daily av]age fl[ ( ! riv]1 x w\ld put "o typhoid g]m into e glass ( wat] at ! ,lawr5ce intake1 & at l[ wat] sev]al times z _m proportionately w\ld be add$4 ,?is gives "s conception ( ! dilution requir$ to make a pollut$ wat] safe4 ,"o (t5 he>s ( ! gr[? ( disease-g]ms 9 wat]1 b z f> z ! nor!rn ,unit$ ,/ates & ,europe are conc]n$ !re is no evid5ce :atev] t ?is ev] takes place4 ,!re are h>mless =ms ( bact]ia :i* are capable ( gr[+ ^u less food ?an ! disease-g]ms require & !y (t5 multiply 9 badly-pollut$ wat]s4 ,typhoid-fev] g]ms live = a long] or %ort] p]iod1 & f9ally die )\t gr[?4 ,! few laboratory exp]im5ts :i* h seem$ to %[ an increase ( typhoid g]ms 9 wat] h be5 made "u conditions s widely diff]5t f ^? ( natural wat]c\rses t !y h no value4#dh ,! proportionate numb] ( cases ( typhoid fev] among ! us]s ( a pollut$ wat] v>ies ) ! numb] ( typhoid g]ms 9 ! wat]4 ,excessive pollution causes sev]e epidemics or cont9u$ high dea?-rates accord+ z ! infection is cont9u$ or int]mitt5t4 ,slight infection causes relatively few cases ( fev]4 ,pittsburg & ,allegh5y1 tak+ _! wat]-supplies f bel[ ! outlets ( "s ( _! own sew]s1 h suff]$ sev]ely 7#ajc4b & #abg4d dea?s f typhoid fev] annually p] #ajj1jjj1 respectively1 f #ahhh to #ahib74 ,:eel+1 ,w4 ,va41 ) simil> conditions 9 #ahij1 0 ev5 worse1 a dea? rate ( #cde p] #ajj1jjj f ?is cause be+ report$1 :ile ,albany _h only comp>atively mild epidemics f ! less directly & grossly pollut$ ,hudson4 ,lawr5ce & ,l[ell1 tak+ _! wat] f ! ,m]rimac1 bo? _h = _m ye>s cont9u$ excessive rates1 increas+ gradually ) increas+ pollution2 & ! city hav+ ! mo/ pollut$ s\rce _h ! high] rate4 ,9 ,b]l9 & ,altona1 9 w9t]1 ) op5 filt]s1 epidemics ( typhoid fev] foll[$ decreas$ effici5cy ( filtration1 b ! epidemics 7 (t5 s mild t !y w\ld h entirely escap$ obs]vation "u pres5t ,am]ican conditions4 ,*icago has = ye>s suff]$ f typhoid fev]1 & ! rate has fluctuat$1 z f> z reliable in=mation c be obta9$1 ) ! fluctuations 9 ! pollution ( ! lake wat]4 ,an unusual dis*>ge ( ! ,*icago ,riv] results 9 a high] dea?-rate4 ,ab&on+ ! %ore inlet ne> ! m\? ( ! ,*icago ,riv] 9 #ahib1 result$ 9 ! foll[+ ye> 9 a r$uction ( #fj p] c5t 9 ! typhoid fev] dea?-rate4#di ,?is r$uction %[s1 n t ! pres5t intakes are safe1 b simply t !y are less pollut$ ?an ! old ones to an ext5t measur$ by ! r$uction 9 ! dea?-rate4 ,x is n suppos$ t 9 an epidemic ( typhoid fev] caus$ by pollut$ wat] e s+le p]son contracts ! disease directly by dr9k+ ! wat]4 ,on ! contr>y1 typhoid fev] is (t5 communicat$ 9 o!r ways4 ,if we h 9 ! fir/ place a ?\s& cases 9 a city caus$ directly by ! wat]1 !y w be foll[$ by a l>ge numb] ( o!r cases result+ directly f ! pres5ce 9 ! city ( ! fir/ ?\s& cases4 ,! conditions favor+ ?is spread may v>y 9 diff]5t w>ds1 result+ 9 consid]able local v>iations 9 ! dea?-rates4 ,"s p]sons also w suff] :o did n dr9k any tap-wat]4 ,^! facts1 always not$ 9 epidemics1 af=d no gr\nd = refus+ to believe1 9 ! pres5ce ( direct evid5ce1 t ! wat] 0 ! cause ( ! fev]4 ,^! additional cases are ! indirect if n ! direct result ( ! wat]4 ,! broad fact t cities ) pollut$ wat]-supplies z a rule h high typhoid-fev] dea?-rates1 & cities ) good wat]-supplies d n 7except 9 ! occasional cases ( milk epidemics1 or :]e !y are ov]run by cases contract$ 9 neighbor+ cities ) bad wat]1 z is ! case ) "s ( ,*icago's suburbs71 is at once ! be/ evid5ce ( ! damage f bad wat] & measure ( its ext5t4 ,! conditions :i* remove or de/roy ! sewage bact]ia 9 a wat] t5d to make x safe4 ,! mo/ important ( !m are3 7#a7 dilution2 7#b7 "t1 all[+ ! bact]ia to die 7sunlight may aid 9 ?is process1 al?\gh effective sun%9e _c rea* ! l[] lay] ( turbid wat]s or ?r\gh ice72 7#c7 s$im5tation1 all[+ !m to g to ! bottom1 :]e !y ev5tually die2 & 7#d7 natural or artificial filtration4 ,9 riv]s1 di/ance is ma9ly useful 9 af=d+ "t1 & also1 "u "s conditions1 9 all[+ opportunities = s$im5tation4 ,?us a di/ance ( #ejj miles requires a week = wat] travell+ ?ree miles an h\r to pass1 & w all[ v important *anges to take place4 ,! old !ory t wat] purifies itself 9 runn+ a c]ta9 di/ance has no adequate f\ndation z f> z bact]ia are conc]n$4 ,"s purification takes place ) ! "t involv$ 9 ! passage1 b its ext5t has be5 greatly ov]e/imat$4 ,! "t requir$ = ! bact]ia to die simply f natural causes is consid]able2 c]ta9ly n less ?an ?ree or f\r weeks c be dep5d$ ^u ) any confid5ce4 ,9 /orage res]voirs ?is action is (t5 consid]able1 & x is = ?is reason t ,am]ican wat]-supplies f l>ge /orage res]voirs are1 z a rule1 mu* m heal?y ?an ^? drawn f riv]s or pollut$ lakes1 ev5 :5 ! s\rces ( ! =m] are some:at pollut$4 ,! wat]-supplies ( ,new ,york & ,bo/on may be cit$ z examples4 ,9 _m o!r wat]-works op]ations ! entire "t f ! pollution to ! consumption ( ! wat] is b a few days or ev5 less1 & "t does n mat]ially improve wat] 9 ?is p]iod4 ,s$im5tation removes bact]ia only sl[ly1 z might be expect$ f _! exce$+ly small size2 & 9 addition _! specific gravity probably is b slightly great] ?an t ( wat]4 ,! ,lawr5ce res]voir1 hold+ f #aj to #ad days' supply1 effect$1 by ! comb9$ effect ( "t & s$im5tation1 a r$uction ( #ij p] c5t ( ! bact]ia 9 ! raw wat]4 ,9 spite ( ?is ! city suff]$ sev]ely & cont9u\sly f fev]4 ,x w\ld probably h suff]$ ev5 m1 h[ev]1 _h x n be5 = ?is r$uction4 ,no?+ is kn[n ( ! removal ( bact]ia by s$im5tation f fl[+ riv]s1 b1 consid]+ ! sl[ness ) :i* ! process takes place 9 /&+ wat]1 x is evid5t t we _c hope = v mu* 9 /reams1 & especially rapid /reams1 :]e ! opportunities = s$im5tation are /ill less favorable4 ,filtration z practic$ 9 ,europe removes promptly & c]ta9ly a v l>ge proportion ( ! bact]ia--probably1 "u all prop] conditions1 ov] #ii p] c5t1 & is ?us mu* m effective 9 purification ?an ev5 weeks ( /orage or long fl[s 9 riv]s4 ,! places us+ filt]$ wat] h1 9 g5]al1 extremely l[ dea?-rates f typhoid fev]4 ,! fev] :i* has occurr$ at a few places draw+ _! raw wat] f greatly pollut$ s\rces has result$ f improp] conditions :i* c be avoid$1 & af=ds no gr\nd = d\bt ( ! effici5cy ( prop]ly conduct$ filtration4 ,correspond+ evid5ce has n yet be5 produc$ 9 connection ) ! me*anical filt]s :i* h be5 l>gely us$ 9 ! ,unit$ ,/ates2 b ! bact]ial effici5cies secur$ ) !m1 "u prop] conditions1 & ) en\gh coagulant1 h be5 su* z to w>rant ! belief t !y also w s]ve to greatly dim9i% ! dang] f su* infection1 al?\gh !y h n %[n !mselves equal 9 ?is respect to s& filt]s4 ,! ma9 po9t is t disease-g]ms %all n be pres5t 9 our dr9k+-wat]4 ,if !y c be kept out 9 ! fir/ place at reasonable exp5se1 t is ! ?+ to d4 ,innoc5ce is bett] ?an rep5tance4 ,if !y _c be kept out1 we mu/ take !m out aft]w>ds2 x does n matt] mu* h[ ?is is done1 s long z ! "w is ?or\gh4 ,s$im5tation & /orage may accompli% mu*1 b _! action is too sl[ & (t5 unc]ta94 ,filtration prop]ly c>ri$ out removes bact]ia promptly & ?or\ghly & at a reasonable exp5se4 ,,app5dices4 ,app5dix ,i4 ,,rules ,,( ,,! ,,g]man ,,gov]nm5t ,,9 ,,reg>d ,,to ,,! ,,filtration ,,( ,,surface-,,wat]s ,,us$ ,,= ,,public ,,wat]-,,supplies4 ,rules some:at simil> to ^? ( :i* a translation is giv5 bel[ 7 fir/ issu$ by ! ,imp]ial ,bo>d ( ,heal? 9 #ahib4 ,^! rules 7 reg>d$ z unnecess>ily rigid1 & a petition 0 pres5t$ to ! gov]nm5t sign$ by #cg wat]-works eng9e]s & directors reque/+ a revision4#ej ,z a result a conf]5ce 0 organiz$ consi/+ ( #ad memb]s4#ea ,khl] presid$1 & ,ko*1 ,gaffsky1 ,w]n]1 ,gn!r1 & ,re9cke repres5t$ ! ,imp]ial ,bo>d ( ,heal?4 ,! bact]iologi/s 7 repres5t$ by ,flgge1 ,wolffhgel1 & ,frnkel1 :ile ,be]1 ,fis*]1 ,l9dley1 ,mey]1 & ,piefke 7 ! eng9e] memb]s4 ,?is conf]5ce prep>$ ! #ag articles giv5 bel[ 9 ! fir/ days ( ,janu>y1 #ahid4 ,a little lat] ! fir/ #af articles 7 issu$ to all ,g]man local au?orities1 sign$ by ,bosse1 m9i/] ( ! 8,gei/li*510 & ,haase1 m9i/] ( ! int]ior1 & !y are consid]$ z b9d+ ^u all wat]-works us+ surface-wat]4 ,! bact]ial exam9ations 7 comm5c$ ,april #a1 #ahid1 by mo/ ( ! cities :i* _h n previ\sly _h !m4 ,al?\gh ! articles d n deal ) rate ( filtration1 or ! precautions aga9/ sn[ & ice1 !y h a v great int]e/ bo? because !y are an (ficial expression1 & on acc\nt ( ! p]sonal /&+ ( ! m5 :o prep>$ !m4 99 99 99 99 99 #a4 ,9 judg+ ( ! quality ( a filt]$ surface-wat] ! foll[+ po9ts %\ld be especially obs]v$3 a4 ,! op]ation ( a filt] is to be reg>d$ z satisfactory :5 ! filtrate conta9s ! smalle/ possible numb] ( bact]ia1 n exce$+ ! numb] :i* practical exp]i5ce has %[n to be atta9able ) good filtration at ! works 9 "q4 ,9 ^? cases :]e !re are no previ\s records %[+ ! possibilities ( ! works & ! influ5ce ( ! local conditions1 especially ! "* ( ! raw wat]1 & until su* in=mation is obta9$1 x is to be tak5 z ! rule t a satisfactory filtration w nev] yield an efflu5t ) m ?an ab\t #ajj bact]ia p] cubic c5timet]4 b4 ,! filtrate mu/ be z cle> z possible1 &1 9 reg>d to color1 ta/e1 temp]ature1 & *emical composition1 mu/ be no worse ?an ! raw wat]4 #b4 ,to all[ a complete & con/ant control ( ! bact]ial effici5cy ( filtration1 ! filtrate f ea* s+le filt] mu/ be exam9$ daily4 ,any sudd5 increase 9 ! numb] ( bact]ia %\ld cause a suspicion ( "s unusual di/urbance 9 ! filt]1 & %\ld make ! sup]9t5d5t m att5tive to ! possible causes ( x4 #c4 ,filt]s mu/ be s con/ruct$ t samples ( ! efflu5t f any "o ( !m c be tak5 at any desir$ "t = ! bact]iological exam9ation m5tion$ 9 #a4 #d4 ,9 ord] to secure uni=mity ( me?od1 ! foll[+ is recomm5d$ z ! /&>d me?od = bact]ial exam9ation3 ,! nutri5t m$ium consi/s ( #aj p] c5t meat extract gelat9e ) peptone1 #aj cc4 ( :i* is us$ = ea* exp]im5t4 ,two samples ( ! wat] "u exam9ation are to be tak51 "o ( #a cc4 & "o ( #a_/b cc4 ,! gelat9e is melt$ at a temp]ature ( #cj to #ce ,c41 & mix$ ) ! wat] z ?or\ghly z possible 9 ! te/-tube by tipp+ back & =?1 & is !n p\r$ ^u a /]ile glass plate4 ,! plates are put "u a bell-j> :i* /&s ^u a piece ( blott+-pap] saturat$ ) wat]1 & 9 a room 9 :i* ! temp]ature is ab\t #bj ,c4 ,! result+ colonies are c\nt$ aft] #dh h\rs1 & ) ! aid ( a l5s4 ,if ! temp]ature ( ! room 9 :i* ! plates are kept is l[] ?an ! above1 ! developm5t ( ! colonies is sl[]1 & ! c\nt+ mu/ be correspond+ly po/pon$4 ,if ! numb] ( colonies 9 #a cc4 ( ! wat] is great] ?an ab\t #ajj1 ! c\nt+ mu/ be done ) ! help ( ! ,wolffhgel's app>atus4 #e4 ,! p]son entru/$ ) ! c>ry+-out ( ! bact]ial exam9ations mu/ pres5t a c]tificate t he possesses ! necess>y qualifications1 & :]ev] possible he %all be a regul> employ ( ! wat]-works4 #f4 ,:5 ! efflu5t f a filt] does n correspond to ! hygi5ic requirem5ts x mu/ n be us$1 unless ! cause ( ! unsatisfactory "w has already be5 remov$ dur+ ! p]iod cov]$ by ! bact]ial exam9ations4 ,9 case a filt] = m ?an a v %ort "t yields a poor efflu5t1 x is to be put out ( s]vice until ! cause ( ! tr\ble is f\nd & correct$4 ,x is1 h[ev]1 recogniz$ f pa/ exp]i5ce t sometimes unavoidable conditions 7high wat]1 etc47 make x impossible1 f an eng9e]+ /&po9t1 to secure an efflu5t ( ! quality /at$ 9 #a4 ,9 su* cases x w be necess>y to get along ) a poor] quality ( wat]2 b at ! same "t1 if ! conditions dem& x 7outbreak ( an epidemic1 etc471 a suitable notice %\ld be issu$4 #g4 ,e s+le filt] mu/ be s built t1 :5 an inf]ior efflu5t results1 :i* does n con=m to ! requirem5ts1 x c be disconnect$ f ! pure-wat] pipes & ! filtrate all[$ to be wa/$1 z m5tion$ 9 #f4 ,?is wa/+ %\ld 9 g5]al take place1 s f> z ! arrangem5t ( ! works w p]mit x3 7#a7 ,imm$iately aft] scrap+ a filt]2 & 7#b7 ,aft] replac+ ! s& to ! orig9al dep?4 ,! sup]9t5d5t mu/ himself judge1 f previ\s exp]i5ce ) ! cont9ual bact]ial exam9ations1 :e!r x is necess>y to wa/e ! wat] aft] ^! op]ations1 &1 if s1 h[ long a "t w probably elapse be=e ! wat] rea*es ! /&>d purity4 #h4 ,! be/ s&-filtration requires a lib]al area ( filt]-surface1 all[+ pl5ty ( res]ve1 to secure1 "u all local conditions1 a mod]ate rate ( filtration adapt$ to ! "* ( ! raw wat]4 #i4 ,e s+le filt] %all be indep5d5tly regulat$1 & ! rate ( filtration1 loss ( head1 & "* ( ! efflu5t %all be kn[n4 ,also ea* filt] %all1 by itself1 be capable ( be+ completely empti$1 &1 aft] scrap+1 ( hav+ filt]$ wat] introduc$ f bel[ until ! s& is fill$ to ! surface4 #aj4 ,! velocity ( filtration 9 ea* s+le filt] %all be capable ( be+ arrang$ to give ! mo/ favorable results1 & %all be z regul> z possible1 q free f sudd5 *anges or int]ruptions4 ,on ?is acc\nt res]voirs mu/ be provid$ l>ge en\gh to balance ! h\rly fluctuation 9 ! consumption ( wat]4 #aa4 ,! filt]s %all be s arrang$ t _! work+ %all n be influ5c$ by ! fluctuat+ level ( ! wat] 9 ! filt]$-wat] res]voir or pump-well4 #ab4 ,! loss ( head %all n be all[$ to become s great z to cause a break+ ?r\gh ( ! upp] lay] on ! surface ( ! filt]4 ,! limit to :i* ! loss ( head c be all[$ to g )\t damage is to be det]m9$ = ea* works by bact]ial exam9ations4 #ac4 ,filt]s %all be con/ruct$ ?r\gh\t 9 su* a way z to insure ! equal action ( e "p ( _! area4 #ad4 ,! sides & bottoms ( filt]s mu/ be made wat]-tight1 & special pa9s mu/ be tak5 to avoid ! dang] ( passages or loose places ?r\gh :i* ! unfilt]$ wat] on ! filt] might f9d its way to ! filt]$-wat] *annels4 ,to ?is end special pa9s %\ld be tak5 to make & keep ! v5tilators = ! filt]$-wat] *annels absolutely tight4 #ae4 ,! ?ickness ( ! s&-lay] %all be s great t "u no circum/ances %all x be r$uc$ by scrap+ to less ?an #cj cm4 7 #ab in*es71 & x is desirable1 s f> z local conditions all[1 to increase ?is m9imum limit4 ,special att5tion mu/ be giv5 to ! upp] lay] ( s&1 :i* mu/ be arrang$ & cont9ually kept 9 ! condition mo/ favorable = filtration4 ,= ?is reason x is desirable t1 aft] a filt] has be5 r$uc$ 9 ?ickness by scrap+ & is ab\t to be refill$1 ! s& bel[ ! surface1 z f> z x is discolor$1 %\ld be remov$ be=e br++ on ! new s&4 #af4 ,e city 9 ! ,g]man empire us+ s&-filt]$ wat] is reque/$ to make a qu>t]ly report ( its work+ results1 especially ( ! bact]ial "* ( ! wat] be=e & aft] filtration1 to ! ,imp]ial ,bo>d ( ,heal? 7,kais]li*5 ,gesundheitsamt71 :i* w keep itself 9 communication ) ! commission *os5 by ! wat]-works eng9e]s 9 reg>d to ^! que/ions2 & x is believ$ t aft] su* /ati/ical in=mation is obta9$ = a p]iod ( ab\t two ye>s "s f>!r judgm5ts c be rea*$4 #ag4 ,! "q z to ! e/abli%m5t ( a p]man5t inspection ( public wat]-works1 &1 if s1 "u :at conditions1 c be be/ answ]$ aft] ! receipt ( ! in=mation indicat$ 9 #af4 ,,app5dix ,,ii4 ,,extracts ,,f 8,,b]i*t ,,des ,,m$ic9al-,,inspectorats ,,des ,,hamburgis*5 ,,/aates ,f,r ,,das ,,jahr #ahib40 ,! foll[+ are translations f ,dr4 ,re9cke's mo/ valuable report ^u ! vital /ati/ics ( ,hamburg = #ahib4 ,i mu* regret t ,i am unable to reproduce 9 full ! v complete & in/ructive tables & diagrams :i* accompany ! report4 ,di>rha & ,*ol]a ,infantum 7page #aj74 8,x is usually assum$ t ! increase ( di>rhal diseases 9 summ] is to be expla9$ by ! high temp]ature1 especially by ! action ( ! heat ^u ! pr9cipal food ( infants--milk4 ,our obs]vations1 h[ev]1 indicate t a deep] cause mu/ be s\ght40 7,tables & diagrams ( dea?s f *ol]a infantum by mon?s = ,hamburg & = ,altona ) ! mean temp]atures1 #ahga-ahib47 8,f ^! x appe>s t ! highe/ mon?ly mortality ( ea* ye> 9 ,hamburg occurr$ #g times 9 ,july1 #ac times 9 ,augu/1 & #c times 9 ,septemb]1 & sub/antially ! same 9 ,altona4 ,if "o comp>es ! correspond+ temp]atures1 x is f\nd t 9 ! ?ree ye>s #ahhf1 #ahia1 & #ahib1 ) high ,septemb] mortalities1 especially ! fir/ two ( !m1 _h _! maximum temp]ature mu* e>li]1 9 fact e>li] ?an usual4 ,?r\gh\t1 ! correspond5ce betwe5 dea?s & temp]atures is n well m>k$4 ,repeat$ high temp]atures 9 ,may & ,june h nev] be5 foll[$ by a notable am\nt ( *ol]a infantum1 al?\gh su* p]iods h la/$ = a consid]able "t4 ,= example1 t[>d ! end ( ,may1 #ahib1 = a long "t ! temp]ature 0 high] ?an 9 ! foll[+ ,augu/1 :5 ! *ol]a infantum appe>$4 8,! foll[+ obs]vations are /ill m int]e/+4 ,z is se5 f ! diagram1 9 addition to ! annual rise 9 summ] !re is also a small] increase 9 ! w9t]1 :i* is especially m>k$ 9 ,altona4 ,9 #ahib ?is w9t] outbreak 0 great] ?an ! summ] "o1 & ne>ly z great 9 #ahhj & 9 #ahhh4 ,! few ye>s :5 ?is w9t] increase 0 n m>k$1 #ahgf-g1 #ahgg-h1 #ahha-b1 #ahhc-d1 7 w>m w9t]s 9 :i* ! mean temp]ature did n g bel[ ! freez+-po9t4 ,x is also to be not$ t ! "t ( ?is w9t] outbreak is mu* m v>iable ?an t ( ! summ] "o4 ,9 #ahhg ! greate/ mortality 0 9 ,novemb]2 9 #ahhi 9 ,febru>y2 9 o!r ye>s 9 ,decemb] or ,janu>y1 & 9 ,altona1 9 #ahhf & #ahhh1 9 ,m>*1 :i* is suffici5t evid5ce t x 0 n ! result ( ,*ri/mas fe/ivities4 8,f>!r1 ! w9t] di>rha ( ,hamburg & ( ,altona are n p>allel z is ! case 9 summ]4 ,9 ,hamburg ! greate/ mortality g5]ally comes be=e ,new ,ye>'s2 9 ,altona "o to two mon?s lat]4 8,9 ,bock5dahl's ,g5]alb]i*t b] das ff5tli*e ,gesundheitswes5 d] ,prov9z ,s*leswig-,hol/e9 fr das ,jahr #ahgj1 page #aj1 we read3 #8,yet m rem>kable 0 an epidemic ( *ol]a infantum 9 ,altona 9 ,febru>y :i* prov$ fatal to #dc *ildr54 ,^! cases 7 di/ribut$ 9 e "p ( ! city1 & c\ld n be expla9$ by ! heal? (fic] until he asc]ta9$ t ! wat] company _h suppli$ unfilt]$ wat] to ! city4 ,?is occurr$ = a few days only 9 ,janu>y1 & 0 ! only "t 9 ! :ole ye> t unfilt]$ ,elbe wat] 0 deliv]$4 ,h[ev] little reason !re may be to believe t !re 0 a connection betwe5 ^! circum/ances1 future int]ruptions ( ! s]vice ( filt]$ wat] %\ld be mo/ critically wat*$1 z only 9 ?is way c reliable conclusions be rea*$4 ,)\t attempt+ to draw any sci5tific conclusions f ! fact1 ,i _c d less ?an record t1 prior to ! outbreak ( *ol]a on ,augu/ #bj1 #ahga1 unfilt]$ toge!r ) filt]$ wat] _h be5 suppli$ to ! city ,augu/ #aa to #ah4 ,! action ( ! au?orities 0 !n ju/ifi$ :5 !y =bade 9 future ! supply ( unfilt]$ wat] except 9 cases ( mo/ urg5t necessity1 z 9 case ( g5]al conflagration2 & 9 su* a case1 or 9 case ( int]ruption due to brok5 pipes1 t ! public %\ld be suitably w>n$4' 8,! au?or ( ?is p>agraph1 ,dr4 ,kraus1 became lat] ! heal? (fic] ( ,hamburg1 & 9 an op9ion writt5 by him 9 #ahgd1 & n[ be=e me1 he mo/ e>ne/ly urg$ ! adoption ( s&-filtration 9 ,hamburg1 & cites ! above obs]vations 9 support ( 8 position4 ,9 ! annual report ( vital /ati/ics ( ,hamburg = #ahge he says t x is q possible t ! addition ( unfilt]$ ,elbe wat] to milk is ! cause ( ! high mortality f *ol]a infantum1 z comp>$ ) ,london1 & ?is idea 0 (t5 aft]w>d express$ by him4 ,s9ce !n s mu* evid5ce has accumulat$ t 8 view may fairly be consid]$ prov$4 8,= ! in=mation ( read]s n famili> ) local conditions1 a m5tion ( ! s\rces ( ! wat]-supplies up to ! pres5t "t us$ by ,hamburg & ,altona w be useful4 ,bo? cities take _! entire wat]-supplies f ! ,elbe--,altona f a po9t ab\t #g miles bel[ ! dis*>ge ( ! sewage ( bo? cities1 ,hamburg f ab\t #g miles above4 ,! raw wat] at ,altona is ?us pollut$ by ! sewage f ! population ( bo? cities1 hav+ n[ toge!r ov] #gjj1jjj inhabitants1 & conta9s 9 g5]al #bj1jjj to #dj1jjj or m bact]ia p] cubic c5timet]4 ,! raw wat] ( ,hamburg has1 h[ev]1 accord+ to ! "t ( ye> & tide1 f #bjj to #ejjj1 b "h also occasionally mu* high] numb]s are obta9$ :5 ! ebb tide c>ries sewage up to ! intake4 ,h[ (t5 ?is takes place is n accurately kn[n1 b mo/ frequ5tly 9 summ] :5 ! riv] is l[1 m r>ely 9 w9t] & 9 times ( flood4 ,rec5t bact]ial exam9ations %[ t x occurs mu* m frequ5tly ?an 0 =m]ly assum$ f float exp]im5ts4 ,?is wat] is pump$ directly to ! city raw1 :ile t = ,altona is c>efully filt]$4 8,ye>s ago ,i express$ ! op9ion t ! repeat$ typhoid epidemics 9 ,altona /ood 9 direct connection ) di/urbances ( ! action ( ! filt]s by fro/1 :i* result 9 ! supply ( insuffici5tly purifi$ wat]4 ,walli*s 9 ,altona has also come to ?is conclusion z a result ( ext5d$ obs]vation1 & rec5tly ,rob]t ,ko* has expla9$ ! little w9t] epidemic ( *ol]a 9 ,altona 9 ! same way1 ?us support+ our !ory4 ,:5 op5 filt]s are clean$ 9 cold1 fro/y wea!r ! bact]ia 9 ! wat] are n suffici5tly held back by ! filt]s4 ,su* di/urbances ( filtration n only prec$$ ! explosive epidemics ( typhoid fev] ( #ahhf1 #ahhg1 #ahhh1 #ahia1 & #ahib1 & ! *ol]a outbreaks ( #ahga & #ahic1 b also ! w9t] outbreaks ( *ol]a infantum :i* h be5 s (t5 repeat$4 ,x _c be d\bt$ t ^! ph5om5a be> ! relation to ea* o!r ( cause & effect4 ,x is ?us expla9$ :y 9 ! w>m w9t]s no su* outbreaks h tak5 place1 & also :y ! *ol]a infantum 9 w9t] is n p>allel 9 ,hamburg & ,altona4 99 99 99 99 99 8,a f>!r support ( ?is idea is furni%$ by ,b]l91 :]e 9 ! same way fro/ has repeat$ly int]f]$ ) filtration4 ,9 ! foll[+ table are %[n ! dea?s f di>rha & *ol]a infantum = a few w9t] p]iods hav+ unusual increases 9 mortality 9 comp>ison ) ! bact]ia 9 ! wat]-supply40 7,^! tables %[ t 9 ,m>*1 #ahhf1 ,m>*1 #ahhh1 ,febru>y-,m>*1 #ahhi1 & ,febru>y1 #ahia1 high numb]s ( bact]ia result$ f fro/ di/urbance at ! ,/ralau works1 & 9 e case !y 7 foll[$ by greatly increas$ dea?-rates f di>rhal diseases4--,a4 ,h47 8,no "o :o sees ?is exhibition c d\bt t "h also ! supply ( inadequately purifi$ wat] has e "t co/ ! lives ( _m *ildr540 7#ajj to #djj or m ea* "t4--,a4 ,h47 8,ev5 m conclusive is ! evid5ce1 publi%$ by ! ,b]l9 ,heal? ,(fice1 t ?is increase 0 conf9$ to ^? p>ts ( ! city suppli$ f ,/ralau0 7) op5 filt]s4--,a4 ,h471 8& t ! p>ts suppli$ f ! bett] ,tegel works took no "p 9 ! outbreaks1 :i* 0 exactly ! case ) ! well-kn[n typhoid epidemic ( ,febru>y & ,m>*1 #ahhi4444 ,x 0 also f\nd t ^? *ildr5 nurs$ by _! mo!rs or by wet-nurses did n suff]1 b only ^? f$ on ! milk ( animals or o!r sub/itutes1 & :i* 9 any case 7 mix$ ) m or less wat]40 ,"u ,*ol]a1 page #bh1 he says3 8,! revis$ /ati/ics "h giv5 diff] slightly f prelim9>y figures previ\sly issu$ & widely publi%$40 7,! full tables1 :i* _c be "h reproduc$1 %[ #af1ief cases & #hfje dea?s4 #hadf ( ! dea?s occurr$ 9 ! mon? end+ ,septemb] #ba4 ,( ^!1 #agii 7 "u #e ye>s old2 #ggf 7 #e to #ae2 #gdd1 #ae to #be2 #cebj1 #be to #ej2 #acfi1 #ej to #gj2 & #cig ov] #gj or ( unkn[n age4 ,! bulk ( ! cases 7 ?us among mature p1 *ildr51 except v "y *ildr51 suff]+ ! lea/ sev]ely ( any age class47 8,! epidemic began on ,augu/ #af1 9 ! port :]e e>li] outbreaks h also _h _! orig94 ,! orig9al s\rce ( ! infection has n be5 asc]ta9$ ) c]ta9ty1 b 0 probably f "o ( two s\rces4 ,ei!r x came f c]ta9 ,jews1 j arriv$ f *ol]a-/rick5 ,russia1 :o 7 encamp$ 9 l>ge numb]s ne> ! ,am]ican pi]1 or ! infection came f ,havre1 :]e *ol]a _h be5 pres5t f ! middle ( ,july4 ,p]haps ! g]ms came 9 %ips 9 wat]-balla/ :i* 0 dis*>g$ at ,hamburg1 :i* is s mu* m probable1 z ! sewage ( ,havre is dis*>g$ directly into ! docks4 8,x is rem>kable t 9 ,altona1 comp>$ to ! total numb] ( cases1 v few *ildr5 _h *ol]a1 :ile 9 ! epidemic ( #ahga ! *ildr5 suff]$ sev]ely4 ,?is may be expla9$ by suppos+ t ! *ol]a ( #ahib 9 ,altona 0 n introduc$ by wat]1 b by o!r means ( infection4444 8,x is well kn[n t ! dr9k+-wat] 7( ,hamburg7 is suppos$ to h be5 f ! fir/ ! c>ri] ( ! *ol]a-g]ms4 ,9 support ( ?is view ! foll[+ po9ts are especially to be not$3 8#a4 ,! explosive rapidity ( attack4 ,! (t5-comp>$ epidemic 9 ,muni* 9 #ahed1 :i* c\ld n h come f ! wat] is *>act]i/ically diff]5t 9 t its rise 0 mu* sl[] & 0 foll[$ by a gradual decl9e4 ,9 ,hamburg1 ) six times z l>ge a population1 ! height ( ! epidemic 0 rea*$ ,augu/ #bg1 only #ab days aft] ! fir/ cases ( sickness1 :ile 9 ,muni* #be days 7 requir$4 ,9 ,hamburg also ! bulk ( ! cases 7 conf9$ to #ab days1 f ,augu/ #be to ,septemb] #e1 :ile 9 ,muni* ! "t 0 twice z long4 8#b4 ,! exact limit ( ! epidemic to ! political b\nd>y betwe5 ,hamburg & ,altona & ,w&sbeck1 :i* also agrees ) ! b\nd>y betwe5 ! respective wat]-supplies1 :ile o!r diff]5ces 7 entirely abs5t4 ,hamburg _h = #ajjj inhabitants #bf4ca cases & #ac4ci dea?s1 b ,altona only #c4ha cases & #b4ac dea?s1 & ,w&sbeck #c4jf cases & #b4ji dea?s4 8#c4 ,! old exp]i5ce ( *ol]a 9 fre%-wat] ports1 & ! analogy ( _m e>li] epidemics4 ,9 ?is connection ! above-m5tion$ epidemic ( #ahga 9 ,altona has a special int]e/1 ev5 ?\gh "s ( ! conclusions ( ,bock5dahl's 9 8 report ( #ahga are op5 to objection4 ,fir/ !re 7 #c dea?s ,augu/ #c1 :i* 7 n at once foll[$ by o!rs4 ,!n unfilt]$ ,elbe wat] 0 suppli$ ,augu/ #aa to #ah4 ,on ! #ai? an outbreak ( *ol]a ext5d$ to all p>ts ( ! city1 :i* rea*$ its height ,augu/ #be & #bf1 & aft]w>ds gradually decreas$4 ,9 all #aje p]sons di$ ( *ol]a & #ahf 7#agi ( !m *ildr57 ( di>rha4 ,9 ,hamburg1 f\r times z l>ge1 only #ada p]sons di$ ( *ol]a at ?is "t1 ?us proportionately a small] numb]4 ,! conditions 7 !n ! rev]se ( ^? ( #ahib1 an infection ( ! ,altona wat] & a comp>ative immunity 9 ,hamburg4 8,x is object$ t ! *ol]a-g]ms 7 n f\nd 9 ! wat] 9 #ahib4 ,to my k !y 7 fir/ look$ =1 & !n ) imp]fect me?ods1 9 ! second half ( ,septemb]4 ,9 ! aft]-epidemics at ,altona1 !y 7 f\nd 9 ! riv]-wat] by ,r4 ,ko* by ! use ( bett] me?ods4 8,x is q evid5t t ! g]ms 7 also di/ribut$ by o!r me?ods ?an by ! city wat]1 especially by dock-labor]s :o became infect$ :ile at _! "w & ?us set up little second>y epidemics :]e !y w5t or liv$4444 ,^! labor]s & sailors1 especially on ! small] riv]-boats1 _h an enorm\sly great] proportionate am\nt ( *ol]a ?an o!rs4444 ,^! labor]s d n live exclusively ne> ! wat]1 b to a measure 9 all p>ts ( ! city40 7,& 9 ,altona & ,w&sbeck4--,a4 ,h47 8,altona _h #e dea?s f *ol]a ,decemb] #be to ,janu>y #d1 & #ai ,janu>y #bc to ,febru>y #aa1 & no m4 ,z not$ above1 ?is is attribut$ to ! wat]-supply1 & to defective filtration 9 pres5ce ( fro/4444 8,! *ol]a c\ld nev] h rea*$ ! proportion :i* x did1 _h ! improvem5ts 9 ! dr9k+-wat] be5 e>li] complet$40 ,fur!r acc\nts ( ! wat]-supplies ( ,altona & ( ,hamburg & ( ! new filtration works at ! latt] city are giv5 9 ,app5dices ,,vii & ,,viii4 ,,app5dix ,,iii4 ,,me?ods ,,( ,,s&-,,analysis4 7,f ! ,annual ,report ( ! ,massa*usetts ,/ate ,bo>d ( ,heal? = #ahib47 ,a k ( ! sizes ( ! s&-gra9s =ms ! basis ( _m ( ! computations4 ,?is in=mation is obta9$ by means ( me*anical analyses4 ,! s& sample is sep>at$ into portions hav+ gra9s ( def9ite sizes1 & f ! weight ( ! sev]al portions ! relative quantities ( gra9s ( any size c be comput$4 ,collection ( ,samples4--,9 %ipp+ & h&l+1 samples ( s& are be/ kept 9 _! natural moi/ condition1 z !re is !n no t5d5cy to sep>ation into portions ( unequal-siz$ gra9s4 ,"u no circum/ances %\ld diff]5t mat]ials be mix$ 9 ! same sample4 ,if ! mat]ial "u exam9ation is n homog5e\s1 samples ( ea* grade %\ld be tak5 9 sep>ate bottles1 ) prop] notes 9 reg>d to location1 quantity1 etc4 ,eight-ounce wide-neck$ bottles are mo/ conv5i5t = s& samples1 b ) gravels a l>g] quantity is (t5 requir$4 ,duplicate samples = comp>ison aft] obta9+ ! results ( analyses are (t5 useful4 ,sep>ation into ,portions hav+ ,gra9s ( ,def9ite ,sizes4--,?ree me?ods are employ$ = p>ticles ( diff]5t sizes--h&-pick+ = ! /ones1 sieves = ! s&s1 & wat] elutriation = ! extremely f9e p>ticles4 ,ignition1 or det]m9ation ( album9oid ammonia1 might be add$ = det]m9+ ! quantity ( organic matt]1 :i*1 z a matt] ( conv5i5ce1 is assum$ to consi/ ( p>ticles less ?an #j4ja millimet] 9 diamet]4 ,! me?od ( h&-pick+ is ord9>ily appli$ only to p>ticles :i* rema9 on a sieve two me%es to an in*4 ,! /ones ( ?is size are spread out s t all are 9 sight1 & a def9ite numb] ( ! l>ge/ are select$ & weigh$4 ,! diamet] is calculat$ f ! av]age weight by ! me?od to be describ$1 :ile ! p]c5tage is reckon$ f ! total weight4 ,ano!r set ( ! l>ge/ rema9+ /ones is !n pick$ out & weigh$ z be=e1 & s on until ! sample is exhau/$4 ,) a little practice ! eye enables "o to pick out ! l>ge/ /ones q accurately4 ,) small] p>ticles ?is process becomes too labori\s1 on acc\nt ( ! l>ge numb] ( p>ticles1 & sieves are !re=e us$ in/ead4 ,! s& = sift+ mu/ be entirely free f moi/ure1 & is ord9>ily dri$ 9 an ov5 at a temp]ature some:at above ! boil+-po9t4 ,! quantity tak5 = analysis %\ld r>ely exce$ #ajj-bjj grams4 ,! sieves are made f c>efully-select$ brass-wire gauze1 hav+1 z ne>ly z possible1 squ>e & ev5-siz$ me%es4 ,! frames are ( metal1 fitt+ into ea* o!r s t sev]al sieves c be us$ at once )\t loss ( mat]ial4 ,x is a great conv5i5ce to h a me*anical %ak]1 :i* w take a s]ies ( sieves & give !m a uni=m & suffici5t %ak+ 9 a %ort "t2 b )\t ?is good results c be obta9$ by h&-%ak+4 ,a s]ies :i* has prov$ v satisfactory has sieves ) approximately #b1 #d1 #f1 #aj1 #bj1 #dj1 #gj1 #ajj1 #adj1 & #bjj me%es to an in*2 b ! exact numb]s are ( no consequ5ce1 z ! actual sizes ( ! p>ticles are reli$ ^u1 & n ! numb] ( me%es to an in*4 ,x c be easily %[n by exp]im5t t :5 a mix$ s& is %ak5 ^u a sieve ! small] p>ticles pass fir/1 & z ! %ak+ is cont9u$ l>g] & l>g] p>ticles pass1 until ! limit is rea*$ :5 almo/ no?+ w pass4 ,! la/ & l>ge/ p>ticles pass+ are collect$ & measur$1 & !y repres5t ! sep>ation ( t sieve4 ,! size ( sep>ation ( a sieve be>s a tol]ably def9ite relation to ! size ( ! me%1 b ! relation is n to be dep5d$ ^u1 ow+ to ! irregul>ities 9 ! me%es & also to ! fact t ! f9] sieves are wov5 on a diff]5t patt]n f ! co>s] ones1 & ! p>ticles pass+ ! f9] sieves are some:at l>g] 9 proportion to ! me% ?an is ! case ) ! co>s] sieves4 ,= ^! reasons ! sizes ( ! s&-gra9s are det]m9$ by actual measurem5ts1 reg>dless ( ! size ( ! me% ( ! sieve4 ,x has n be5 f\nd practicable to ext5d ! sieve-sep>ations to p>ticles bel[ #j4aj millimet] 9 diamet] 7correspond+ to a sieve ) ab\t #bjj me%es to an in*71 & = su* p>ticles elutriation is us$4 ,! portion pass+ ! f9e/ sieve conta9s ! great] "p ( ! organic matt] ( ! sample1 ) ! exception ( roots & o!r l>ge undecompos$ matt]s1 & x is usually be/ to remove ?is organic matt] by ignition at ! l[e/ possible heat be=e proce$+ to ! wat]-sep>ations4 ,! loss 9 weight is reg>d$ z organic matt]1 & calculat$ z bel[ #j4ja millimet] 9 diamet]4 ,9 case ! m9]al matt] is decompos$ by ! necess>y heat1 ! ignition mu/ be omitt$1 & an approximate equival5t c be obta9$ by multiply+ ! album9oid ammonia ( ! sample by #ej4eb ,9 ?is case x is necess>y to d$uct an equival5t am\nt f ! o!r f9e portions1 z o!rwise ! analyses :5 express$ 9 p]c5tages w\ld add up to m ?an "o hundr$4 ,five grams ( ! ignit$ f9e p>ticles are put 9 a beak] #ij millimet]s high & hold+ ab\t #bcj cubic c5timet]s4 ,! beak] is !n ne>ly fill$ ) di/ill$ wat] at a temp]ature ( #bj ,c41 & ?or\ghly mix$ by bl[+ into x air ?r\gh a glass tube4 ,a l>g] quantity ( s& ?an #e grams w n settle uni=mly 9 ! quantity ( wat] giv51 b less c be us$ if desir$4 ,! rapidity ( settlem5t dep5ds ^u ! temp]ature ( ! wat]1 s t x is q important t no mat]ial v>iation 9 temp]ature %\ld occur4 ,! mix$ s& & wat] is all[$ to /& = fifte5 seconds1 :5 mo/ ( ! sup]natant liquid1 c>ry+ ) x ! great] "p ( ! p>ticles less ?an #j4jh millimet]1 is rapidly decant$ into a suitable vessel1 & ! rema9+ s& is aga9 mix$ ) an equal am\nt ( fre% wat]1 :i* is aga9 p\r$ (f aft] fifte5 seconds1 c>ry+ ) x mo/ ( ! rema9+ f9e p>ticles4 ,?is process is once m repeat$1 aft] :i* ! rema9+ s& is all[$ to dra91 & is !n dri$ & weigh$1 & calculat$ z above #j4jh millimet] 9 diamet]4 ,! f9] decant$ s& w h suffici5tly settl$ 9 a few m9utes1 & ! co>s] p>ts at ! bottom are wa%$ back into ! beak] & treat$ ) wat] exactly z be=e1 except t "o m9ute int]val is n[ all[$ = settl+4 ,! s& rema9+ is calculat$ z above #j4jd millimet]1 & ! portion bel[ #j4jd is e/imat$ by diff]5ce1 z its direct det]m9ation is v t$i\s1 & no m accurate ?an ! e/imation by diff]5ce :5 suffici5t c>e is us$4 ,det]m9ation ( ! ,sizes ( ! ,s&-gra9s4--,! sizes ( ! s&-gra9s c be det]m9$ 9 ei!r ( two ways--f ! weight ( ! p>ticles or f micromet] measurem5ts4 ,= conv5i5ce ! size ( ea* p>ticle is consid]$ to be ! diamet] ( a sph]e ( equal volume4 ,:5 ! weight & specific gravity ( a p>ticle are kn[n1 ! diamet] c be readily calculat$4 ,! volume ( a sph]e is #a_/f;d1 & is also equal to ! weight divid$ by ! specific gravity4 ,) ! ,lawr5ce mat]ials ! specific gravity is uni=mly #b4fe )9 v n>r[ limits1 & we h w_/#b4fe #a_/f;d4 ,solv+ = d we obta9 ! =mula d 4#iw1 :]e d is ! diamet] ( a p>ticle 9 millimet]s & w its weight 9 milligrams4 ,z ! av]age weight ( p>ticles1 :5 n too small1 c be det]m9$ ) precision1 ?is me?od is v accurate1 & altoge!r ! mo/ satisfactory = p>ticles above #j4aj millimet]2 t is1 = all sieve sep>ations4 ,= ! f9] p>ticles ! me?od is inapplicable1 on acc\nt ( ! va/ numb] ( p>ticles to be c\nt$ 9 ! smalle/ portion :i* c be accurately weigh$1 & 9 ^! cases ! sizes are det]m9$ by micromet] measurem5ts4 ,z ! s&-gra9s are n sph]ical or ev5 regul> 9 %ape1 consid]able c>e is requir$ to asc]ta9 ! true mean diamet]4 ,! mo/ accurate me?od is to measure ! long diamet] & ! middle diamet] at "r angles to x1 z se5 by a microscope4 ,! %ort diamet] is obta9$ by a micromet] screw1 focuss+ fir/ ^u ! glass ^u :i* ! p>ticle re/s & !n ^u ! highe/ po9t to be f\nd4 ,! mean diamet] is !n ! cube root ( ! product ( ! ?ree obs]v$ diamet]s4 ,! middle diamet] is usually ab\t equal to ! mean diamet]1 & c g5]ally be us$ = x1 avoid+ ! tr\blesome measurem5t ( ! %ort diamet]s4 ,! sizes ( ! sep>ations ( ! sieves are always det]m9$ f ! v la/ s& :i* passes ?r\gh 9 ! c\rse ( an analysis1 & ! results s obta9$ are q accurate4 ,) ! elutriations av]age samples are inspect$1 & e/imates made ( ! range 9 size ( p>ticles 9 ea* portion4 ,"s /ray p>ticles bo? above & bel[ ! normal sizes are usually pres5t1 & ev5 ) ! greate/ c>e ! result is only an approximation to ! tru?2 /ill1 a s]ies ( results made 9 /rictly ! same way %\ld be ?or\ghly satisfactory1 not)/&+ possible mod]ate errors 9 ! absolute sizes4 ,calculation ( ,results4--,:5 a mat]ial has be5 sep>at$ into portions1 ea* ( :i* is accurately weigh$1 & ! range 9 ! sizes ( gra9s 9 ea* portion det]m9$1 ! weight ( ! p>ticles f9] ?an ea* size ( sep>ation c be calculat$1 & ) en\gh prop]ly select$ sep>ations ! results c be plott$ 9 ! =m ( a diagram1 & measurem5ts ( ! curve tak5 = int]m$iate po9ts ) a fair degree ( accuracy4 ,?is curve ( results may be drawn ^u a uni=m scale1 us+ ! actual figures ( sizes & ( p] c5ts by weight1 or ! log>i?ms ( ! figures may be us$ 9 "o or bo? directions4 ,! me?od ( plott+ is n ( vital importance1 & ! me?od = any set ( mat]ials :i* gives ! mo/ easily & accurately drawn curves is to be pref]r$4 ,9 ! diagram publi%$ 9 ! ,report ( ! ,mass4 ,/ate ,bo>d ( ,heal? = #ahia1 page #dcj1 ! log>i?mic scale 0 us$ 9 "o direction1 b 9 _m in/ances ! log>i?mic scale c be us$ to advantage 9 bo? directions4 ,) ?is me?od x has be5 f\nd t ! curve is (t5 almo/ a /raight l9e ?r\gh ! l[] & mo/ important section1 & v accurate results are obta9$ ev5 ) a small] numb] ( sep>ations4 ,examples ( ,calculation ( ,results4--,foll[+ are examples ( repres5tative analyses1 %[+ ! me?od ( calculation us$ ) ! diff]5t me?ods ( sep>ation employ$ ) v>i\s mat]ials4 ,i4 ,,analysis ,,( ,a ,,gravel ,,by ,,h&-,,pick+1 #aa1hgj ,,grams ,,tak5 ,,= ,,analysis4 ---------------------------------------- --------------------------- ,numb] ,total ,av]age ,e/imat$ ,correspond+ ,total ,p] ,c5t ( ,weight ( ,weight ( ,weight ( ,size4 ,weight ( ,/ones ,portion4 ,/ones4 ,smalle/ ,millimet]s4 ( ,total 9 ,grams4 ,milligrams4 ,/ones4 ,/ones ,weight ,portion4 ,milligrams4 ,small],small] 7,l>ge/ ?an ?an ,select$ ?is ?is ,/ones47 ,size4 ,size4 ---------------------------------------- --------------------------- 4444 4444 4444 4444 #aa1hgj #ajj #aj #c1cbj #ccb1jjj #bej1jjj #ef #h1eej #gb #aj #a1icj #aic1jjj #afe1jjj #di #f1fbj #ef #aj #a1chj #ach1jjj #abd1jjj #de #e1bdj #dd #bj #b1bjj #aaj1jjj #ic1jjj #da #c1jdj #bf #bj #a1ebj #gf1jjj #fd1jjj #cf #a1ebj #ac #bj #a1jjj #ej1jjj #cf1jjj #cj #ebj #d4d #bj #dfj #bc1jjj #aj1jjj #bj #fj 4#e #aj #dj #d1jjj #b1jjj #aa #bj 4#b ,du/ #bj 4444 4444 4444 4444 4444 ---------------------------------------- --------------------------- ,! weight ( ! smalle/ /ones 9 a portion giv5 9 ! f\r? column is e/imat$ 9 g5]al z ab\t half-way betwe5 ! av]age weight ( all ! /ones 9 t portion & ! av]age weight ( ! /ones 9 ! next f9] portion4 ,! f9al results are %[n by ! figures 9 full-fac$ type 9 ! la/ & ?ird f ! la/ columns4 ,by plott+ ^! figures we f9d t #aj p] c5t ( ! /ones are less ?an #ce millimet]s 9 diamet]1 & #fj p] c5t are less ?an #ea millimet]s4 ,! 8uni=mity coeffici5t10 z describ$ bel[1 is ! ratios ( ^! numb]s1 or #a4df1 :ile ! 8effective size0 is #ce millimet]s4 ,,ii4 ,,analysis ,,( ,a ,,s& ,,by ,,means ,,( ,,sieves4 ,a portion ( ! sample 0 dri$ 9 a porcela9 di% 9 an air-ba?4 ,weight dry1 #aaj4i grams4 ,x 0 put into a s]ies ( sieves 9 a me*anical %ak]1 & giv5 "o hundr$ turns 7equal to ab\t sev5 hundr$ s+le %akes74 ,! sieves 7 !n tak5 ap>t1 & ! portion pass+ ! f9e/ sieve weigh$4 ,aft] not+ ! weight1 ! s& rema9+ on ! f9e/ sieve1 b pass+ all ! co>s] sieves1 0 add$ to ! fir/ & aga9 weigh$1 ?is process be+ repeat$ until all ! sample 0 ^u ! scale1 weigh+ #aaj4g grams1 %[+ a loss by h&l+ ( only #j4b gram4 ,! figures 7 z foll[s3 ------------------------------------ ,size ( ,sep>ation ,quantity,p] ,c5t ,sieve ( ?is ( ,s& ( ,m>k$4 ,sieve4 ,pass+4 ,total ,millimet]s4,grams4 ,weight4 ------------------------------------ #aij 4#aje 4#e 4#e #adj 4#ace #a4c #a4b #ajj 4#ahb #d4a #c4g #fj 4#cbj #bc4b #ba4j #dj 4#df #ef4g #ea4b #bj 4#ic #hi4a #hj4e #aj #b4jd #ajd4f #id4c #f #c4ij #aaj4g #ajj4j ----------------------------------- ,plott+ ! figures 9 heavy-fac$ type1 we f9d f ! curve t #aj & #fj p] c5t respectively are f9] ?an 4#be & 4#fb millimet]1 & we h = effective size1 z describ$ above1 4#be1 & = uni=mity coeffici5t #b4e4 ,,iii4 ,,analysis ,,( ,a ,,f9e ,,mat]ial ,,) ,,elutriation4 ,! entire sample1 #gd grams1 0 tak5 = analysis4 ,! sieves us$ 7 n ! same z ^? 9 ! previ\s analysis1 & in/ead ( mix+ ! v>i\s portions on ! scale !y 7 sep>ately weigh$4 ,! sift+s 7 z foll[s3 ,rema9+ on sieve m>k$ #aj1 above #b4b millimet]s #a4e grams ,rema9+ on sieve m>k$ #bj1 above 4#ih millimet]s #g4j grams ,rema9+ on sieve m>k$ #dj1 above 4#df millimet]s #bb4j grams ,rema9+ on sieve m>k$ #gj1 above 4#bd millimet]s #bj4b grams ,rema9+ on sieve m>k$ #adj1 above 4#ac millimet]s #i4b grams ,pass+ sieve #adj1 bel[ 4#ac millimet]s #ad4a grams ,! #ad4a grams pass+ ! #adj sieve 7 ?or\ghly mix$1 & "o ?ird1 #d4g grams1 tak5 = analysis4 ,aft] ignition j bel[ a r$ heat 9 a radiator1 ! weight 0 dim9i%$ by #j4dg gram4 ,! portion above 4#jh millimet] & betwe5 4#jd & 4#jh millimet]1 sep>at$ z describ$ above1 weigh$ respectively #a4bg & #a4ga grams1 & ! portion bel[ 4#jd millimet] 0 e/imat$ by diff]5ce #d4g - 7#j4dg #a4bg #a4ga7 to be #a4be grams4 ,multiply+ ^! quantities by #c1 we obta9 ! correspond+ quantities = ! entire sample1 & ! calculation ( quantities f9] ?an ! v>i\s sizes c be made z foll[s3 ---------------------------------------- -------------------------- ,size ( ,weight ( all,p] ,c5t by ,weight4 ,l>ge/ ! ,f9] ,weight ( ,size ( ,gra94 ,grams4 ,p>ticles4 ,p>ticles4 all ,f9] ,millimet]s4 ,grams4 ,p>ticles4 ---------------------------------------- -------------------------- ,above #b4bj millimet]s #a4ej 4444 #gd4jj #ajj 4#ih-b4bj millimet]s #g4jj #b4bj #gb4ej #ih 4#df- 4#ih millimet]s #bb4jj 4#ih #fe4ej #hi 4#bd- 4#df millimet]s #bj4bj 4#df #dc4ej #fj 4#ac- 4#bd millimet]s #i4bj 4#bd #bc4cj #cb 4#jh- 4#ac millimet]s #c4ha 4#ac #ad4aj #ai 4#jd- 4#jh millimet]s #e4ac 4#jh #aj4bi #ad 4#ja- 4#jd millimet]s #c4ge 4#jd #e4af #g ,loss on ignition 7assum$ to be less ?an 4#ja millimet]7 #a4da 4#ja #a4da #a4i ---------------------------------------- -------------------------- ,by plott+ ! heavy-fac$ figures we f9d t #aj & #fj p] c5t are respectively f9] ?an 4#jee & 4#df millimet]1 & we h effective size 4#jee millimet] & uni=mity coeffici5t #h4 99 99 99 99 99 ,! effective size & uni=mity coeffici5t calculat$ 9 ?is way h prov$ to be mo/ useful 9 v>i\s calculations1 p>ticul>ly 9 e/imat+ ! friction betwe5 ! s&s & gravels & wat]4 ,! rema9d] ( ! article 9 ! ,report ( ! ,mass4 ,/ate ,bo>d ( ,heal? is devot$ to a discussion ( ^! relations :i* 7 m5tion$ 9 ,*apt] ,,iii ( ?is volume4 ,,app5dix ,,iv4 ,,filt] ,,/ati/ics4 ,,/ati/ics ,,( ,,op]ation ,,( ,,s& ,,filt]s4 ---------------------------------------- ------------------------------- ,total ,area ,av]age ,area (,p]iod1 ,quantity ( ,daily ,filt] ( ,wat] ,filt]s ,yield1 ,surface,million filt]$ ,million9 use1 clean$,gallons ,place4 ,ye> = ,gallons ,million 9 ,"o p] ,acre ,end+4 ,"o ,ye>4 ,daily4 ,acres4 ,gallons ,ye>1 filt]$ ,million p] ,acre4 betwe5 ,gallons4 ,acres4 ,scrap+s4 ---------------------------------------- ------------------------------- ,altona ,m>41 #ahie #a1fbj #d4dd #c4jh #a4de #ca4j #eb ,m>41 #ahif #a1gcj #d4ge #c4jh #a4ee #dh4e #cf ,m>41 #ahig #a1ifj #e4dj #c4jh #a4ge #dd4j #de ,m>41 #ahih #a1idj #e4cj #c4jh #a4gb #cf4e #ec ,am/]dam1 ,dec41 #ahid #a1cij #c4hj #e4dc #j4ga #bc #fb ,riv] ,dec41 #ahif #a1dij #d4jh #e4dc #j4ge #dh #ca ,dec41 #ahig #a1fjj #d4dj #e4dc #j4ha #cj #ec ,am/]dam1 ,dec41 #ahid #b1ccj #f4dj #d4id #a4bi #aaf #bj ,dunes ,dec41 #ahif #b1cfj #f4ej #d4ge #a4cg #ij #bf ,dec41 #ahig #b1bij #f4be #d4ge #a4ca #aji #ba ,a%l&1 ,feb41 #ahig #cih #a4ji #j4ej #b4ah #d4hc #hc ,wis4 ,b]l91 ,m>41 #ahif #ac1jjj #ce4fj #be4aj #a4db total ,m>41 #ahig #ab1ijj #ce4dj #be4aj #a4dj ,m>41 #ahih #ac1bjj #cf4bj #bg4jj #a4cd ,brem5 ,m>41 #ahie #a1aij #c4bg #b4ea #a4ca #ej #bd ,m>41 #ahif #a1bbj #c4cd #c4ba #a4jd #cb4e #ch ,m>41 #ahig #a1bhj #c4ej #c4ba #a4ji #be4b #ej ,m>41 #ahih #a1djj #d4aj #c4ba #a4bh #cd4j #da ,breslau ,m>41 #ahie #b1hdj #g4hj #e4ab #a4eb #de #fd ,m>41 #ahif #b1ifj #h4aj #e4ab #a4eh #dj4j #gd ,m>41 #ahig #b1iij #h4bj #e4ab #a4fj #cg #ha ,m>41 #ahih #c1jfj #h4dj #e4ab #a4fd #dc #ga ,brunn ,dec41 #ahif #a1aaj #c4jd #a4fb #a4hg #h4f #abh ,dec41 #ahig #a1aij #c4be #a4fb #b4jj #i4a #aca ,brunswick ,m>41 #ahie #hae #b4bc #a4dh #a4ea #ad4h #ee ,m>41 #ahif #hdj #b4cj #a4dh #a4ef #ac4c #fc ,m>41 #ahig #hbj #b4be #a4dh #a4eb #ac4g #fj ,m>41 #ahih #hgj #b4ch #a4dh #a4fa #aa4i #gc ,budape/ ,dec41 #ahib #g1cfj #bj4bj #c4jj #f4gj #bed #bi ,cop5hag5 ,dec41 #ahie #b1ccj #f4dj #b4hh #b4bb #de #eb ,dec41 #ahif #b1dij #f4hj #b4hh #b4ce #eb #dh ,dec41 #ahig #b1ehj 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#a4bj #cj #cg ,dec41 #ahig #a1aad #c4jf #b4ej #a4bb #da #bg ,liv]pool ,dec41 #ahif #h1ebj #bc4dj #aj4ib #b4ad #aeh #edec ,london1 all ,dec41 #ahib #fe1ghc #ahj #aji4ge #a4fd #ij filt]s ,dec41 #ahic #aie #aaf4jj #a4fh b n ,dec41 #ahid #fh1gjj #ahh #aag4jj #a4fj includ+ ,dec41 #ahie #gf1ijj #baj #abc4ge #a4gj gr\nd ,dec41 #ahif #gb1dhb #aih #abc4ge #a4fj wat] ,dec41 #ahig #gc1cdj #bja #abe4jj #a4fa ,london1 ,dec41 #ahig #e1cgj #ad4gj #h4jj #a4he ,*elsea ,e4 ,london ,dec41 #ahig #ah1jjj #di4jj #ca4jj #a4eh ,gr& ,dec41 #ahig #h1efj #bc4dj #ba4ge #a4jg ,junction ,lambe? ,dec41 #ahig #aj1cgj #bh4dj #ab4be #b4cj ,new ,riv] ,dec41 #ahig #ae1gej #dc4jj #af4ej #b4fj ,s\?w>k ,dec41 #ahig #ad1hjj #dj4ej #bj4ej #a4ih ,vauxhall ,we/ ,dec41 #ahig #h1iaj #bd4cj #ae4jj #a4fa ,middlesex ,lbeck ,m>41 #ahie #a1ebj #d4ae #a4dj #b4ie #af4b #id ,m>41 #ahif #a1fjj #d4ch #a4dj #c4ac #bd4d #ff ,m>41 #ahig #a1fej #d4ej #a4dj #c4bb #bg4j #fa ,m>41 #ahih #a1gej #d4hj #a4dj #c4db #ch4e #de ,magdeburg ,m>41 #ahie 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,read+1 ,pa4 #j4jg ,w4 ,g4 -------------------- ,totals #ajh #gg1hjf ---------------------------------------- --------------------------- ,special filt]s1 nei!r s& nor me*anical3 ,wilm+ton1 ,del42 ,pop41 #fa1dca2 area1 #aj1jjj sq4 ft42 nom9al capacity1 #aj million gallons4 ,see ,eng4 ,news1 ,vol4 #dj1 p4 #adf4 ,,notes ,,reg>d+ ,,s& ,,filt]s ,,9 ,,! ,,unit$ ,,/ates4 ,,p\ghkeepsie1 ,n4 ,y4 ,design$ by ,james ,p4 ,kirkwood1 built 9 #ahgb1 0 ! e>lie/ ( its k9d 9 ! ,unit$ ,/ates4 ,x 0 enl>g$ by ! ,sup]9t5d5t1 ,*>les ,e4 ,f[l]1 9 #ahif4 ,! walls ( ! orig9al filt]s 7 ( rubble1 & 9 c\rse ( "t develop$ cracks & leak$ badly4 ,! walls ( ! new filt] are ( rubble1 fac$ ) vitrifi$ brick4 ,! filt]s treat ! wat] ( ! ,hudson ,riv]1 :i* is sewage-pollut$ & m or less muddy4 ,description3 ,j\r4 ,n4 ,e4 ,wat] ,works ,assoc41 ,vol4 #ab1 p4 #bji4 ,,hudson1 ,n4 ,y4 ,design$ by ,james ,p4 ,kirkwood1 built 9 #ahgd4 enl>g$ 9 #ahhh4 ,! filt]s are op5 & are us$ = treat+ ! ,hudson ,riv] wat]1 :i* is sewage-pollut$ & m or less muddy4 ,description3 ,eng4 ,news1 ,vol4 #ca1 p4 #dhg4 ,,/4 ,,johnsbury1 ,,vt4 7,e4 ,t4 ,fairbanks ,co47 ,^! filt]s 7 built ab\t #cj ye>s ago1 & h be5 rec5tly enl>g$4 ,! filt]s 7 orig9ally op51 b 7 aft]w>ds cov]$ ) a ro(4 ,! s+le ro( prov$ inadequate to keep !m f freez+1 & a second ro( 0 add$ inside & "u ! ma9 ro(4 ,!y are us$ = filt]+ pond wat]1 :i* is q cle> & n subject to mu* pollution4 ,! wat] supply is "o ( two1 ! o!r is ! t[n supply & is tak5 f ! ,passumpsic ,riv]4 ,no publi%$ description4 ,,nantucket1 ,,mass4 ,design$ by ,j4 ,b4 ,rid]1 built 9 #ahib4 ,?is filt] is us$ to remove organisms f ! res]voir wat] supply4 ,x is only us$ :5 ! organisms are tr\blesome1 & is satisfactory 9 prev5t+ ! ta/es & odors :i* =m]ly result$ f _! pres5ce4 ,description3 ,j\r4 ,n4 ,e4 ,wat] ,works ,assoc41 ,vol4 #h1 p4 #aga2 ,eng4 ,news1 ,vol4 #ca1 p4 #ccf4 ,,lawr5ce1 ,,mass4 ,design$ by ,hiram ,f4 ,mills1 built 9 #ahib-c1 & put 9 op]ation ,septemb]1 #ahic4 ,x is us$ = treat+ ! wat] ( ! ,m]rimac ,riv]1 :i* conta9s a l>ge am\nt ( sewage4 ,description3 ,report ( ! ,mass4 ,/ate ,bo>d ( ,heal?1 #ahic1 p4 #edc2 ,j\r4 ,n4 ,e4 ,wat] ,works ,assoc41 ,vol4 #i1 p4 #dd2 ,eng4 ,news1 ,vol4 #cj1 p4 #ig4 ,,ilion1 ,n4 ,y4 ,design$ by ! ,/anwix ,eng9e]+ ,company & are us$ = treat+ res]voir wat]1 :i* is g5]ally cle> & n subject to pollution4 ,description3 ,eng4 ,news1 ,vol4 #ca1 p4 #dff4 ,,m\nt ,,v]non1 ,n4 ,y4 7,new ,york ,suburban ,wat] ,company47 ,design$ by ,j4 ,n4 ,*e/]1 built 9 #ahid4 ,^! filt]s are simil> 9 g5]al con/ruction to ! ,lawr5ce filt]1 al?\gh ! dim5sions bo? v]tical & horizontal are r$uc$1 & ! area is divid$ into ?ree p>ts4 ,! filt]s are us$ = treat+ res]voir wat]1 :i* is g5]ally q cle>1 b :i* is pollut$ by a consid]able am\nt ( sewage4 ,s9ce ! use ( filt]s ! r$uction 9 ! typhoid fev] dea?-rate has be5 v great4 ,description3 ,eng4 ,news1 ,vol4 #cb1 p4 #aee4 ,,mil=d1 ,,mass4 ,design$ by ,f4 ,l4 ,nor?rop4 ,?is filt] is v simple 9 con/ruction1 & is us$ = filt]+ ,*>les ,riv] wat] z an auxili>y supply4 ,description3 ,j\r4 ,n4 ,e4 ,wat] ,works ,assoc41 ,vol4 #aj1 p4 #bfb4 ,,gr& ,,=ks1 ,n4 ,d4 ,design$ by ,w4 ,s4 ,russell4 ,^! filt]s are cov]$ ) ro(s4 ,!y treat ! wat] f ! ,r$ ,riv]1 :i* is v muddy1 & also sewage-pollut$1 & :i* =m]ly caus$ typhoid fev]4 ,description3 ,eng4 ,news1 ,vol4 #cc1 p4 #cda4 ,,a%l&1 ,,wis4 ,design$ by ,william ,:eel]1 built 9 #ahie4 ,! ,a%l& filt]s 7 ! fir/ vault$ masonry filt]s to be con/ruct$ 9 ! ,unit$ ,/ates1 & are us$ = treat+ ! bay wat]1 :i* is pollut$ ) sewage1 & is at times muddy f ! riv] wat] dis*>g+ into ! bay ne> ! intake4 ,! filt]s are bel[ ! bay level1 & receive wat] f x by gravity4 ,description3 ,j\r4 ,n4 ,e4 ,wat] ,works ,assoc41 ,vol4 #aa1 p4 #cja2 ,eng4 ,news1 ,vol4 #ch1 p4 #cch4 ,,lamb]tville1 ,n4 ,j4 ,design$ by ,*ur*ill ,hung]=d1 & built 9 #ahif4 ,^! are op5 filt]s ) e>? embankm5ts1 = filtration ( res]voir wat]4 ,description3 ,eng4 ,news1 ,vol4 #cf1 p4 #d4 ,,f> ,,rockaway1 ,l4 ,i4 7,que5s ,c\nty ,wat] ,company47 ,design$ by ,*>les ,r4 ,bettes1 ,eng9e] 9 ,*>ge2 ,*>les ,b4 ,bru% ,co41 ,*ief ,eng9e]s2 & ,all5 ,haz51 ,consult+ ,eng9e]4 ,con/ruct$ 9 #ahif4 ,^! masonry filt]s 7 us$ = ! removal ( iron f well wat]s4 ,!y are also design$ to be suitable = ! filtration ( c]ta9 brook wat]s :i* are available z auxili>y supplies1 b ! brook wat] has be5 b r>ely us$4 ,description3 ,eng4 ,record1 ,vol4 #dj1 p4 #dab4 ,,r$ ,,bank1 ,n4 ,j4 7,rumson ,improvem5t ,company47 ,design$ by ,all5 ,haz51 built 9 #ahig4 ,!y are simil> 9 con/ruction to ! ,f> ,rockaway filt]s1 & are us$ = iron removal only4 ,description3 ,eng4 ,record1 ,vol4 #dj1 p4 #dab4 ,,hamilton1 ,n4 ,y4 ,design$ by ! ,/anwix ,eng9e]+ ,company1 & 7 built 9 #ahie to filt] lake wat]4 ,description3 ,eng4 ,news1 ,vol4 #ci1 p4 #bed4 ,,little ,,falls1 ,n4 ,y4 ,design$ by ,/eph5 ,e4 ,babcock4 ,^! filt]s are op51 & 7 built 9 #ahih1 & are us$ = filt]+ riv] wat]4 ,description3 ,eng4 ,record1 ,vol4 #ch1 p4 #g4 ,,som]swor?1 ,n4 ,h4 ,design$ by ,william ,:eel]4 ,^! 7 ! second vault$ filt]s to be built 9 ! ,unit$ ,/ates4 ,! supply is f ! ,salmon ,falls ,riv] & fl[s to ! filt]s by gravity1 ! filt]s be+ bel[ ! riv] level4 ,description3 ,eng4 ,news1 ,vol #dj1 p4 #ceh2 ,eng4 ,record1 ,vol4 #ch1 p4 #bgj4 ,,b]wyn1 ,,p5na4 ,design$ by ,j4 ,w4 ,l$\x4 ,^! op5 filt]s are us$ = filt]+ creek wat]4 ,description3 ,eng4 ,news1 ,vol4 #da1 p4 #aej4 ,,h>risburg1 ,,p5na4 7,/ate ,lunatic ,hospital47 ,design$ by ,all5 ,haz52 op5 masonry filt]s1 us$ = treat+ ! wat] f a small creek :i* is (t5 muddy & is subject to pollution4 ,no publi%$ description4 ,,albany1 ,n4 ,y4 ,design$ by ,all5 ,haz54 ,con/ruct$ #ahih-ii4 ,?is 0 ! ?ird & is ! l>ge/ vault$ masonry filt] plant yet con/ruct$ 9 ! ,unit$ ,/ates4 ,x is us$ = filt]+ ! ,hudson ,riv] wat]1 :i* is slightly muddy & mu* pollut$ by sewage4 ,description3 ,eng4 ,news1 ,vol4 #ci1 p4 #ia2 ,vol4 #dj1 p4 #bed4 ,,rock ,,isl&1 ,,ill4 ,design$ by ,jacob ,a4 ,h>man4 ,op5 filt]s ) embankm5ts1 us$ = filt]+ ! ,mississippi ,riv] wat]1 :i* is v muddy & also pollut$ by sewage4 ,no publi%$ description4 99 99 99 99 99 ,,capacity ,,( ,,filt]s4 ,e/imat+ ! total additional area ( s& filt]s = :i* figures are n available at #ajj acres1 & ! maximum capacity ( s& filt]s at ?ree million gallons p] acre daily1 & ( me*anical filt]s at ?ree million gallons p] ?\s& squ>e feet ( filt]+ area1 ! total filt]+ capacity ( all ! filt]s 9 ! _w us$ = public wat] supplies 9 #ahii is ne>ly #afjj million gallons daily1 ( :i* #ae p] c5t is repres5t$ by me*anical filt]s & #he p] c5t by s& filt]s4 ,9 ! ,unit$ ,/ates1 includ+ ,wilm+ton1 ! total filt]+ capacity is ne>ly #cjj million gallons daily1 ( :i* #ah p] c5t is repres5t$ by s& filt]s1 #gi p] c5t by me*anical filt]s1 & #c p] c5t by a special type ( filt]s4 ,,app5dix ,v4 ,,london',s ,,wat]-,,supply4 ,london alone among great capitals is suppli$ ) wat] by private companies4 ,!y are1 h[ev]1 "u gov]nm5t sup]vision1 & ! rates *>g$ = wat] are regulat$ by law4 ,!re are eight companies1 ea* ( :i* supplies its own sep>ate di/rict1 s t !re is no competition :atev]4 ,"o ( ! companies supply+ #dfj1jjj p uses only gr\nd-wat] drawn f deep wells 9 ! *alk1 b ! o!r sev5 companies dep5d ma9ly ^u ! riv]s ,?ames & ,lea = _! wat]4 ,all wat] s drawn is filt]$1 & mu/ be satisfactory to ! wat] exam9]1 :o is requir$ to inspect ! wat] suppli$ by ea* company at frequ5t int]vals1 & ! results ( ! exam9ations are publi%$ ea* mon?4 ,9 #ahic ! av]age daily supply 0 #bce1jjj1jjj gallons1 ( :i* ab\t #dj1jjj1jjj 7 drawn f ! *alk1 #abe1jjj1jjj f ! ,?ames1 & #gj1jjj1jjj f ! ,lea4 ,=m]ly "s ( ! wat] companies drew wat] f ! ,?ames )9 ! city :]e x 0 grossly pollut$1 & ! plagues & *ol]a :i* =m]ly ravag$ ,london 7 9 "p due to ?is fact4 ,^! intakes 7 ab&on$ _m ye>s ago1 & all ! companies n[ draw _! wat] f po9ts outside ( ! city & its imm$iate suburbs4 ,! area ( ! wat]%$ ( ! ,?ames above ! intakes ( ! wat] companies is #cedh squ>e miles1 & ! population liv+ ^u x 9 #ahia 0 #a1jef1dae4 ,! ,?ames ,cons]vancy ,bo>d has control ( ! ma9 riv] = its :ole l5g?1 & ( all tribut>ies )9 t5 miles 9 a /raight l9e ( ! ma9 riv]1 b has no jurisdiction ov] ! m remote fe$]s4 ,! area dra9$ is ess5tially agricultural1 ) b little manufactur+1 & !re are b few l>ge t[ns4 ,9 ! area com+ "u ! cons]vators !re are b six t[ns ) populations above #aj1jjj & an aggregate population ( #agj1jjj1 & !re are b two or ?ree o!r l>ge t[ns on ! rema9+ area m ?an t5 miles f ! riv]4 ,^! pr9cipal t[ns are z foll[s3 ,t[n4 ,population #ahia4 ,di/ance above ,wat] ,intakes4 ,read+ #fj1jed #di miles ,ox=d #de1gia #hg miles ,new ,sw9don #bg1bie #aaf miles ,high ,wycomb #ac1dce #cc miles ,w9dsor #ab1cbg #ah miles ,maid5head #aj1fjg #be miles ,guild=d #ad1cai #bj miles ,guild=d is outside ( ! cons]vators' area4 ,all ( ! above t[ns treat _! sewage by irrigation4 ,among ! places t are reg>d$ z ! mo/ dang]\s are ,*]tsey & ,/a9es1 ) populations ( #ibae & #ejfj1 only #h & #aa miles above ! intakes respectively4 ,^! t[ns are only p>tially sew]$ & /ill dep5d ma9ly on cesspools4 ,an attempt is made to treat ! little sewage :i* !y produce ^u l&1 b ! "w has n z yet be5 sy/ematically c>ri$ out4 ,!re are also sev]al small t[ns ( #cjjj inhabitants or less ^u ! upp] riv] :i* d n treat _! sewage s f> z !y h any1 b1 ow+ to _! great di/ance1 ! dang] f !m is mu* less ?an f ,*]tsey & ,/a9es4 ,tw5ty-"o ( ! pr9cipal t[ns ^u ! wat]%$ h sewage f>ms1 & !re are no *emical precipitation plants n[ 9 use4 ,boats ^u ! riv] are n all[$ to dra9 into x1 b are compell$ to provide receptacles = _! sewage1 & facilities are provid$ = remov+ & dispos+ ( x2 & z an additional precaution no boat is all[$ to an*or )9 five miles ( ! intakes4 ,! cons]vators ( ! riv] ,lea h control ( its entire dra9age area1 :i* is ab\t #dfj squ>e miles1 measur$ f ! ,ea/ ,london wat] intakes1 & has a population ( #ahi1bhg4 ,on ?is wat]%$ !re is b a s+le t[n ) m ?an #aj1jjj inhabitants1 ?is be+ ,lutton ne> ! headwat]s ( ! riv]1 ) a population ( #cj1jje4 ,! sewage f ,lutton & f sev5te5 small] places is treat$ ^u l&4 ,no crude sewage is kn[n to be ord9>ily dis*>g$ into ! riv]4 ,at ,h]e=d1 elev5 miles above ! ,ea/ ,london intakes1 !re is a *emical precipitation plant4 ,! cons]vators d n reg>d ?is treatm5t z satisfactory1 & h rec5tly conduct$ an exp5sive lawsuit aga9/ ! local au?orities to compel !m to fur!r treat _! efflu5t4 ,! suit 0 lo/1 ! c\rt hold+ t no actual injury to heal? _h be5 %[n4 ,x is especially int]e/+ to note t ( ! ?irty-n9e places on ! ,?ames & ! ,lea giv+ _! sewage sy/ematic treatm5t !re is b a s+le place us+ *emical precipitation1 & !re x is n consid]$ satisfactory4 ,=m]ly q a numb] ( ^! t[ns us$ o!r processes ?an l& treatm5t1 b 9 e case b ,h]e=d l& treatm5t has be5 sub/itut$4 ,9 reg>d to ! effici5cy ( ! sewage f>ms1 x is believ$ t 9 ord9>y wea!r ! :ole ( ! sewage p]colates ?r\gh ! l&1 & ! inspectors ( ! ,cons]vancy ,bo>ds /rongly object to its be+ all[$ to pass ov] ! surface into ! /reams4 ,! l&1 h[ev]1 is = ! mo/ "p imp]vi\s1 z comp>$ to ,massa*usetts & ,g]man sewage f>ms1 & 9 times ( heavy /orms ! l& (t5 has all ! wat] x c take )\t receiv+ ev5 ! ord9>y fl[ ( sewage1 & mu* less ! increas$ /orm-fl[4 ,at su* times ! sewage ei!r does g ov] ! surface1 or p]haps m frequ5tly is dis*>g$ directly into ! riv]s )\t ev5 a pret5ce ( treatm5t4 ,! cons]vators app>5tly reg>d ?is z an unavoidable evil & d n vigor\sly oppose x4 ,x is ! !ory t1 ow+ to ! increas$ dilution ) ! /orm-fl[s1 ! matt] is comp>atively h>mless1 al?\gh x w\ld seem t ! r$uc$ "t requir$ = x to rea* ! wat]-works intakes might l>gely (fset ! effect ( increas$ dilution4 ,! wat] companies h l>ge /orage & s$im5tation bas9s ) an aggregate capacity equal to n9e days' supply1 b ! proportion v>ies widely ) ! diff]5t companies4 ,x is desir$ t ! wat] held 9 res]ve %all be alone us$ :ile ! riv] is 9 flood1 z1 ow+ to its increas$ pollution1 x is reg>d$ z f> m dang]\s ?an ! wat] at o!r times2 b z no record is kept ( ! times :5 raw sewage is dis*>g$1 & no exact in=mation is available 9 reg>d to ! times :5 ! companies d n take 9 raw wat]1 x c safely be assum$ t a consid]able am\nt ( raw sewage does become mix$ ) ! wat] :i* is drawn by ! companies4 ,! wat] drawn f ! riv] is filt]$ ?r\gh #aac filt]s hav+ an area ( #aaf acres4 ,none ( ! filt]s are cov]$1 & ) an av]age ,janu>y temp]ature ( #ci b little tr\ble ) ice is exp]i5c$4 ,a few new filt]s are provid$ ) appliances = regulat+ ! rate on ea* filt] sep>ately & secur+ regul> & det]m9$ rates ( filtration1 b ne>ly all ( ! filt]s are ( ! simple type describ$ on page #dh1 & ! rates ( filtration are subject to m or less viol5t fluctuation1 ! ext5t ( :i* _c be det]m9$4 ,! area ( filt]s is be+ cont9ually increas$ to meet increas+ consumption2 ! approximate areas ( filt]s 9 use hav+ be5 z foll[s3 #ahci ,fir/ filt]s built #ahee #cg acres #ahff #dg acres #ahgf #gg acres #ahhf #ajd acres #ahid #aaf acres ,!re has be5 a t5d5cy to r$uce some:at ! rate ( filtration4 ,9 #ahfh1 ) #ea acres ( filt]s1 ! av]age daily quantity ( wat] filt]$ 0 #aaa1jjj1jjj gallons1 or #b1ahj1jjj gallons p] acre4 ,9 #ahhd1 ) #ig acres ( filt] surface1 ! daily quantity filt]$ 0 #aeg1jjj1jjj gallons1 or #a1fbj1jjj gallons p] acre2 & 9 #ahic1 ) #aaf acres ( filt] surface & #aie1jjj1jjj gallons daily1 ! yield p] acre 0 #a1fhj1jjj gallons4 ,ow+ to ! area ( filt] surface out ( use :ile be+ clean$1 ! v>iations 9 consumption ( wat]1 & ! imp]fections ( ! regulat+ app>atus1 ! actual rates ( filtration are (t5 v mu* high] & at times may easily be d\ble ! figures giv54 ,evid5ce reg>d+ ! heal?fulness ( ! filt]$ riv]-wat] 0 collect$ & exam9$ 9 a mo/ exhau/ive mann] 9 #ahic by a ,royal ,commission appo9t$ to consid] ! wat]-supply ( ! metropolis 9 all its aspects ) ref]5ce to future ne$s4 ,?is commission 0 unable to obta9 any evid5ce :atev] t ! wat] z !n suppli$ 0 unheal?y or likely to become s1 & !y report t ! riv]s c safely be dep5d$ ^u = _m ye>s to come4 ,! numb]s ( dea?s f all causes & f typhoid fev] annually p] million ( inhabitants = ! ye>s #ahhe-ahia 9 ! populations receiv+ _! wat]s f diff]5t s\rces 9 ,london 7 z foll[s3 ,wat] us$4 ,dea?s f ,dea?s f ,all ,causes4 ,typhoid ,fev]4 ,filt]$ ,?ames wat] only #ai1eja #abe ,filt]$ ,lea wat] only #ba1ccd #afg ,k5t wells only #ah1jja #abc ,?ames & ,lea jo9tly #ah1ide #ach ,?ames & ,k5t jo9tly #ah1egg #acc ,! population suppli$ exclusively f ! ,lea by ! ,ea/ ,london ,company is ( a poor] class ?an t ( ! re/ ( ,london1 & ?is may acc\nt = ! slightly high] dea?-rate 9 ?is section4 ,aside f ?is ! rate is rem>kably uni=m & %[s no great diff]5ce betwe5 ! section dr9k+ gr\nd-wat] only & ^? dr9k+ filt]$ riv]-wat]s4 ,! dea?-rate f typhoid fev] is also v uni=m &1 al?\gh high] ?an t ( "s ,cont95tal cities ) excell5t wat]-supplies 7,b]l91 ,vi5na1 ,muni*1 ,dresd571 is v l[--l[] ?an 9 any ,am]ican city ( :i* ,i h records4 ,9 ?is connection1 x 0 %[n by ! ,regi/r>-,g5]al t !re is only a v small am\nt ( typhoid fev] on ! wat]%$s ( ! ,?ames & ,lea1 s t ! dang] ( infection ( ! wat] z di/9ct f pollution is less ?an w\ld o!rwise be ! case4 ,?us = ! sev5 ye>s above m5tion$ ! numb]s ( dea?s f typhoid fev] p] million ( population 7 only #aje & #abj on ! wat]%$s ( ! ,?ames & ! ,lea respectively1 z aga9/ #agf = ! :ole ( ,engl& & ,wales4 ,,london ,,filt]s1 #ahif4 ,tw5ty-six? ,annual ,report ( ! ,local ,gov]nm5t ,bo>d1 pages #bjf-bac4 ---------------------------------------- --------------------------------- ,am\nt ,av]age ,av]age ,rate ,bact]ial ,effici5cy4 ( ,?ickness ( ,filtration4 ,/orage ( ---------------------------------------- ,raw ,s&1 ,imp]ial,millions,maximum4,m9imum4,av]ag e4 ,company4 ,wat]1 ,feet4 ,gallons ,u4 ,s4 ,days4 p] ,gallons ,squ>e p] ,acre ,foot p] ,daily4 ,h\r4 ---------------------------------------- ------------------------------ ,*elsea #ab4j #d4j #a4ge #b4ai #ii4ib #ii4fb #ii4hf ,we/ ,middlesex #e4f #b4ge #a4be #a4ef #ii4id #ia4dh #ii4gi ,s\?w>k ,vauxhall #d4a #b4e #a4e #a4hh #ajj4jj #hd4cc #ig4gg ,gr& ,junction #c4c #b4be #a4fc #b4je #ii4ih #hd4jc #ii4ca ,lambe? #f4j #b4h #b4jh #b4fj #ii4ig #if4de #ii4ha ,new ,riv] #b4b #d4d #a4hi #b4cg #ajj4jj #gg4ad #ii4jg ,ea/ ,london #ae4j #b4j #a4cc #a4fg #ii4ic #ig4jc #ii4ef ---------------------------------------- ------------------------------ ,,app5dix ,,vi4 ,,! ,,b]l9 ,,wat]-,,works4 ,! orig9al works 7 built by an ,engli% company 9 #ahef1 & 7 sold to ! city 9 #ahgc = #g1bjj1jjj4 ,! wat] 0 tak5 f ! riv] ,spree at ! ,/ralau ,gate1 :i* 0 !n above1 b is n[ surr\nd$ by1 ! gr[+ city4 ,! wat] 0 always filt]$1 & ! orig9al filt]s rema9$ 9 use until #ahic1 :5 !y 7 supplant$ by ! new works at ,lake ,mggel4 ,soon aft] acquir+ ! works ! city introduc$ wat] f wells by ,lake ,tegel z a supplem5t>y supply1 b mu* tr\ble 0 exp]i5c$ f cr5o?rix1 an organism gr[+ 9 gr\nd-wat]s conta9+ iron1 & 9 #ahhc ?is supply 0 replac$ by filt]$ wat] f ,lake ,tegel4 ,) rapidly-increas+ pollution ( ! ,spree at ,/ralau ! purity ( ?is s\rce 0 que/ion$1 & 9 #ahic x 0 ab&on$ 7al?\gh /ill held z a res]ve 9 case ( urg5t necessity71 ! supply n[ be+ tak5 f ! riv] t5 miles high] up1 at ,mggel4 ,! wat]%$ ( ! ,spree above ,/ralau1 z ,i f\nd by map measurem5t1 is ab\t #chjj squ>e miles2 ! av]age ra9fall is ab\t #be in*es ye>ly4 ,at extreme l[ wat] ! riv] dis*>ges #deg cubic feet p] second1 or #bie million gallons daily1 & :5 9 flood #egjj cubic feet p] second may be dis*>g$4 ,! city is all[$ by law to take #df million gallons daily = wat]-supply1 & ?is quantity c be drawn ei!r at ,/ralau or at ,mggel4 ,above ,/ralau ! riv] is pollut$ by num]\s manufactories & wa%+ e/abli%m5ts1 & by ! efflu5t f a consid]able "p ( ! city's ext5sive sewage f>ms4 ,! %ipp+ on ?is "p ( ! riv] also is heavy1 & sewage f ! boats is dis*>g$ directly into ! riv]4 ,! av]age numb] ( bact]ia 9 ! ,spree at ?is po9t is some?+ ov] t5 ?\s& p] cubic c5timet]1 & #ii4f p] c5t ( !m 7 remov$ by ! filt]s 9 #ahic4 ,! wat]%$ ( ! ,spree above ! new wat]-works at ,mggel ,i f\nd by map measurem5t to be #bhjj squ>e miles1 & ! l[ wat]-dis*>ge is said to be #bfi million gallons daily4 ,! riv] at ?is po9t fl[s ?r\gh ,lake ,mggel1 :i* =ms a natural s$im5tation-bas91 & ! raw wat] is q cle> except 9 w9dy wea!r4 ,!re 7 #af t[ns on ! wat]%$ ) populations above #bjjj ea* 9 #ahij1 & an aggregate population ( #acb1jjj1 :i* does n include ! population ( ! small] places or c\ntry di/ricts4 ,none ( ^! places purify _! sewage s f> z !y h any4 ,fr/5walde ) a population ( #ab1ice1 & #bb miles above ,mggel1 has surface sew]s dis*>g+ directly into ! riv]4 ,above ,fr/5walde ! riv] runs ?r\gh num]\s lakes :i* probably remove ! effect ( ! pollution f ! m di/ant cities4 ,!re is consid]able %ipp+ on ! riv] = "s miles above ,fr/5walde 7:i* =ms a section ( ! ,fri$ri* ,wilhelm ,canal71 b h>dly any betwe5 ,mggel & ,fr/5walde4 ,! raw wat] at ,mggel conta9s two or ?ree hundr$ bact]ia p] cubic c5timet]1 & is ?us a comp>atively pure wat] be=e filtration4 ,x is slightly peaty & ! filt]$ wat] has a light /raw color4 ,lake ,tegel1 :i* supplies ! o!r "p ( ! city's supply1 is an enl>gem5t ( ! riv] ,havel4 ,! wat]%$ above ,tegel ,i f9d to be ab\t #acej squ>e miles1 & ! annual ra9fall is ab\t #bb in*es4 ,! l[ wat]-dis*>ge is said to be #ahb million gallons daily1 & ! city is all[$ by law to take #bc million gallons = wat]-supply4 ,!re 7 t5 t[ns ^u ! wat]%$ ) populations above #bjjj ea* 9 #ahij1 & ) an aggregate population ( #dd1jjj4 ,( ^! ,tegel is directly ^u ! lake ) a population ( #cjjj1 & ,orani5burg1 #ad miles above1 has a population ( #fjjj & is rapidly increas+4 ,! %ipp+ on ! lake & riv] is heavy4 ,! lake wat] ord9>ily conta9s two or ?ree hundr$ bact]ia p] cubic c5timet]4 ,! lake is %all[ & becomes turbid 9 w9dy wea!r4 ,!re are #ba filt]-b$s at ,tegel ) a comb9$ area ( #ab4dj acres to furni% a maximum ( #bc million gallons ( wat] daily1 & #bb filt]s at ,mggel ) a comb9$ area ( #ab4g acres to deliv] ! same quantity4 ,tw5ty-two m filt]s w be built at ,mggel )9 a few ye>s to purify ! full quantity :i* c be tak5 f ! riv]4 ,all ( ^! filt]s are cov]$ ) brick ar*es support$ by pill>s ab\t #af feet ap>t f c5tre to c5tre 9 ea* direction1 & ! :ole is cov]$ by ne>ly #c feet ( e>?1 mak+ !m q fro/-pro(4 ,! orig9al filt]s at ,/ralau 7 op51 b mu* difficulty 0 exp]i5c$ ) !m 9 w9t]4 ,! bottom ( ! filt]s at ,tegel consi/s ( #h in*es ( concrete above #bj in*es ( pack$ clay & ) #b in*es ( cem5t above1 & slopes slightly f ea* side to ! c5tre4 ,! c5tral dra9 goes ! :ole l5g? ( ! filt]s & has a uni=m cross-section ( ab\t #a_/gcjj ( ! area ( ! :ole b$4 ,!re are no lat]al dra9s1 b ! wat] is br\ght to ! c5tral dra9 by a twelve-in* lay] ( /ones z l>ge z a man's fi/2 above ?is !re is ano!r foot ( gravel ( grad$ sizes support+ two feet ( f9e s&1 :i* is r$uc$ by scrap+ to half its ?ickness be=e ! s& is replac$4 ,! av]age dep? ( wat] above ! s& is ne>ly #e feet4 ,! filt]s are n all[$ to filt] at a rate above #b4eg million gallons p] acre daily1 & at ?is rate ) #gj p] c5t ( ! area 9 s]vice ! :ole legal quantity ( wat] c be filt]$4 ,! filt]s "w at precisely ! same rate day & night1 & ! filt]$ wat] is cont9u\sly pump$ z filt]$ to ample /orage res]voirs at ,*>lott5burg4 ,! pumps :i* lift ! wat] f ! lake to ! filt]s "w aga9/ a head ( #ad feet4 ,! app>atus = regulat+ ! rate ( filtration 0 describ$ on page #ea4 ,z yet no full description ( ! ,mggel works has be5 publi%$1 b !y resemble closely ! ,tegel works4 ,bo? 7 design$ by or "u ! direction ( ! late director ( ! wat]-works1 ,mr4 ,h5ry ,gill4 ,! av]age daily quantity ( wat] suppli$ = ! fiscal ye> end+ ,m>* #ca1 #ahic1 0 #bi1jjj1jjj gallons daily1 :i* e/imate all[s #aj p]c5t = ! slip ( ! pumps4 ,( ?is quantity #i1fej1jjj 0 furni%$ by ,/ralau & #ai1cej1jjj by ,tegel4 ,! greate/ consumption 9 a s+le day 0 #dc1cjj1jjj gallons1 or #bf4f gallons p] head1 :ile ! av]age quantity = ! ye> 0 #ah4d gallons p] head4 ,all wat] )\t exception is sold by met]1 ! prices rang+ f #bg4b c5ts a ?\s& gallons = small consum]s to #ac4f c5ts = l>ge consum]s & manufactur]s4 ,! av]age receipts = all wat] pump$1 includ+ t us$ = public purposes & n paid =1 7 #ae4d c5ts a ?\s& gallons1 aga9/ ! co/ ( production1 #i4h c5ts1 :i* cov]s op]at+ exp5ses1 int]e/ on capital1 & provision = s9k+ fund4 ,?is leaves a h&some net pr(it to ! city4 ,on acc\nt ( ! comp>atively high price ( ! city wat] & ! ease ) :i* well-wat] is obta9$1 ! latt] is almo/ exclusively us$ = runn+ eng9es1 manufactur+ purposes1 etc41 & ?is 9 "p expla9s ! v l[ p]-capita consumption4 ,! volume ( sewage1 h[ev]1 = ! same ye>1 includ+ ra9-wat]1 except dur+ heavy %[]s1 0 only #bi gallons p] head1 %[+ ev5 ) ! private wat]-supplies an extraord9>ily l[ consumption4 ,! friction ( ! wat] 9 ! #d4ge miles ( #c-;foot pipe betwe5 ,tegel & ! res]voir at ,*>lott5burg pres5ts an int]e/+ po9t4 ,:5 well-wat] ) cr5o?rix 0 pump$1 ! friction rose to #cd4e feet1 :5 ! velocity 0 #b4df feet p] second4 ,accord+ to ,h]r ,anklamm1 :o _h *>ge ( ! works at ! "t1 ! friction 0 r$uc$ to #ai4g feet :5 filt]$ wat] 0 us$ & aft] ! pipe _h be5 flu%$1 & ?is has n increas$ ) cont9u$ use4 ,he calculat$ ! friction = ! velocity accord+ to ,d>cy #ae4j feet1 ,lampe #ag4h feet1 ,weisba* #ah4g feet1 & ,prony #ba4e feet4 ,,app5dix ,,vii4 ,,altona ,,wat]-,,works4 ,! ,altona wat]-works are specially int]e/+ z an example ( a wat] drawn f a s\rce pollut$ to a mo/ unusual ext5t3 ! sewage f cities ) a population ( #ggj1jjj1 includ+ its own1 is dis*>g$ into ! riv] ,elbe )9 t5 miles above ! intake & ^u ! same side4 ,! area ( ! wat]%$ ( ! ,elbe above ,altona is ab\t #eb1jjj squ>e miles1 & ! av]age ra9fall is e/imat$ to be ab\t #bh in*es1 v>y+ f #bd or less ne> its m\? to mu* high] quantities 9 ! m\nta9s f> to ! s\?4 ,on ?is wat]%$ !re are #df cities1 :i* 9 #ahij _h populations ( ov] #bj1jjj ea*1 & 9 addition !re is a p]man5t population ^u ! riv]-boats e/imat$ at #bj1jjj1 mak+ 9 all #e1hid1jjj inhabitants1 )\t includ+ ei!r c\ntry di/ricts or ! numb]less cities ) less ?an #bj1jjj inhabitants ea*4 ,! sewage f ab\t #a1gjj1jjj ( ^! p is purifi$ be=e be+ dis*>g$2 & assum+ t z _m p liv+ 9 cities small] ?an #bj1jjj are connect$ ) sew]s z live 9 l>g] places )\t be+ s connect$1 ! sewage ( ov] f\r million p is dis*>g$ untreat$ into ! ,elbe & its tribut>ies4 ,! m important ( ^! s\rces ( pollution are ! foll[+3 ,city ,population ,on :at ,approximate 9 #ahij4 ,riv]4 ,di/ance1 ,miles4 ,%ipp+ #bj1jjj ,altona #adc1cec ,elbe #f ,hamburg #egj1ecd ,elbe #g ,w&sbeck #bj1ehf ,elbe #h ,h>burg #ce1aja ,elbe #aa ,magdeburg #bjb1cbe ,elbe #ahe ,dresd5 #bgf1jhe ,elbe #ced ,b]l9 & suburbs #a1ghg1hei ,havel #bdc ,halle #aja1dja ,saale #bgb ,leipzig #cee1dhe ,el/] #cje ,*emnitz #ach1iee ,mulde #cdj ,prague #caj1dhc ,moldau #ejj ,! sewage ( ,b]l9 & ( mo/ ( its suburbs is treat$ be=e be+ dis*>g$1 & 9 addition ! ,havel fl[s ?r\gh a s]ies ( lakes bel[ ! city1 all[+ bett] opportunities = natural purification ?an 9 ! case ( any ( ! o!r cities4 ,halle treats less ?an a t5? ( its sewage4 ,magdeburg w treat its sewage 9 ! c\rse ( a few ye>s4 ,leipzig1 ,*emnitz1 & o!r places are ?9k+ m or less s]i\sly ( purification4 ,! numb] ( bact]ia 9 ! raw wat] at ,altona fluctuates ) ! tide & is extremely v>iable2 numb]s ( #ej1jjj & #ajj1jjj are n infrequ5t1 b #aj1jjj to #dj1jjj is p]haps ab\t ! usual range4 ,! works 7 orig9ally built by an ,engli% company 9 #ahfj1 & h s9ce be5 greatly ext5d$4 ,!y 7 b\ght by ! city "s ye>s ago4 ,! wat] is pump$ directly f ! riv] to a settl+-bas9 ^u a hill #bhj feet above ! riv]4 ,f ?is x fl[s by gravity ?r\gh ! filt]s to ! slightly l[] pure-wat] res]voir & to ! city )\t fur!r pump+4 ,! filt]s are op51 ) ne>ly v]tical masonry walls1 z describ$ 9 ,kirkwood's report4 ,! cross-section ( ! ma9 und]dra9 is #a_/bhjj ( ! area ( ! b$s4 ,consid]able tr\ble has be5 exp]i5c$ f fro/4 ,) cont9u$ cold wea!r x is extremely difficult to satisfactorily scrape ! filt]s1 & v irregul> rates ( filtration may result at su* times4 ,9 ! la/ few ye>s1 ) sy/ematic bact]ial inve/igation1 x has be5 f\nd t greatly decreas$ effici5cy frequ5tly foll[s cont9u$ cold wea!r1 & ! mild epidemics ( typhoid fev] f :i* ! city has long suff]$ h g5]ally occurr$ aft] ^! times4 ,?us a light epidemic ( typhoid 9 #ahhf came 9 ,m>*1 foll[+ a light epidemic 9 ,hamburg4 ,9 #ahhg a sev]e epidemic 9 ,febru>y foll[$ a sev]e epidemic 9 ,hamburg 9 ,decemb] & ,janu>y4 ,9 #ahhh a sev]e epidemic 9 ,m>* foll[$ an epidemic 9 ,hamburg la/+ f ,novemb] to ,janu>y4 ,hamburg's epidemic ( #ahhi1 com+ 9 w>m wea!r1 ,septemb] & ,octob]1 0 foll[$ by only a v slight increase 9 ,altona4 ,9 #ahia ,altona suff]$ aga9 9 ,febru>y f a sev]e epidemic1 al?\gh v little typhoid _h be5 9 ,hamburg4 ,a less sev]e outbreak also came 9 ,febru>y1 #ahib1 & a /ill slight] "o 9 ,febru>y1 #ahic4 ,9 ! t5 ye>s #ahhb-ahib1 ( five well-m>k$ epidemics1 ?ree broke out 9 ,febru>y & two 9 ,m>*1 :ile two small] outbreaks came 9 ,decemb] & ,janu>y4 ,no important outbreak has ev] occurr$ 9 summ] or 9 ! fall mon?s1 :5 typhoid is usually mo/ preval5t1 ?us %[+ cle>ly ! bad effect ( fro/ ^u op5 filt]s 7see ,app5dix ,,ii74 ,) /eadily increas+ consumption ! s$im5tation-bas9 capacity ( late ye>s has become insuffici5t z well z ! filt]+ area1 & x is n unlikely t ) bett] conditions a mu* bett] result c\ld be obta9$ 9 w9t] ev5 ) op5 filt]s4#fc ,! brilliant a*ievem5t ( ! ,altona filt]s 0 9 ! summ] ( #ahib1 :5 !y protect$ ! city f ! *ol]a :i* s ravag$ ,hamburg1 al?\gh ! raw wat] at ,altona mu/ h conta9$ a va/ly great] quantity ( infecti\s matt] ?an t :i* work$ su* havoc 9 ,hamburg4 ,f ^! records x appe>s t = ab\t n9e mon?s ( ! ye> ! ,altona filt]s protect ! city f ! impurities ( ! ,elbe wat]1 b t dur+ cold wea!r1 ) cont9u$ mean temp]atures bel[ ! freez+-po9t1 su* protection is n completely af=d$1 & bad effects h occasionally result$4 ,not)/&+ ! rec5t con/ruction ( op5 filt]s 9 ,hamburg x appe>s to me t !re mu/ always be m or less dang] f op5 filt]s 9 su* a climate4 ,hamburg's dang]1 h[ev]1 w be mu* less ?an ,altona's on acc\nt ( its bett] intake above ! outlets ( ! sew]s ( ,hamburg & ,altona1 :i* are ! mo/ important po9ts ( pollution at ,altona4 ,,app5dix ,,viii4 ,,hamburg ,,wat]-,,works4 ,! s\rce & quality ( ! wat] previ\sly suppli$ has be5 suffici5tly indicat$ 9 ,app5dix ,,ii4 ,x 0 orig9ally int5d$ to filt] ! wat]1 b ! con/ruction ( filt]s 0 po/pon$ f "t to "t until ! fall ( #ahij1 :5 ! project 0 s]i\sly tak5 up1 & "w 0 comm5c$ 9 ! spr+ ( #ahia4 ,?ree ye>s 7 all[$ = con/ruction4 ,9 #ahib1 h[ev]1 ! epidemic ( *ol]a came1 kill+ #hfje resid5ts & do+ incalculable damage to ! bus9ess int]e/s ( ! city4 ,! heal? au?orities f\nd t ! pr9cipal cause ( ?is epidemic 0 ! pollut$ wat]-supply4 ,to prev5t a possible recurr5ce ( *ol]a 9 #ahic1 ! "w ( con/ruction ( ! filt]s 0 press$ =w>d mu* m rapidly ?an _h be5 int5d$4 ,electric lights 7 provid$ to all[ ! "w to proce$ nights z well z days1 & z a result ! plant 0 put 9 op]ation ,may #bg1 #ahic1 a full ye> be=e ! int5d$ "t4 ,ow+ to ! =c$ con/ruction ! co/ 0 mat]ially increas$4 ,! new works take ! raw wat] f a po9t "o & a half miles f>!r up-/ream1 :]e x is believ$ ! tide c nev] c>ry ! city's own sewage1 z x did frequ5tly to ! old intake4 ,! wat] is pump$ f ! riv] to settl+-bas9s aga9/ heads v>y+ ) tide & ! wat]-level 9 ! bas9s f #h to #bb feet4 ,ea* ( ! f\r settl+-bas9s has an area ( ab\t #aj acres1 &1 ) ! wat] #f4ef feet deep1 holds #bj1ejj1jjj gallons1 or #hb1jjj1jjj gallons 9 all4 ,! works are int5d$ to supply a maximum ( #dh1jjj1jjj gallons daily1 b ! pres5t av]age consumption is only ab\t #ce1jjj1jjj gallons 7#ahib71 or #ei gallons p] head = #fjj1jjj population4 ,?is consumption is reg>d$ z excessive1 & x is hop$ t x w be r$uc$ mat]ially by ! m g5]al use ( met]s4 ,! s$im5tation-bas9s are surr\nd$ by e>!n embankm5ts ) slopes ( #a3c1 ! inn] sides be+ pav$ ) brick above a clay lay]4 ,! wat] fl[s by gravity f ^! bas9s to ! filt]s1 a di/ance ( #a-a_/b miles1 ?r\gh a conduit #h-a_/b feet 9 diamet]4 ,! fl[ ( ! wat] out ( ! bas9s & f ! l[] end ( ! conduit is regulat$ by automatic gates connect$ ) floats1 %[n by ,fig4 #aa1 page #fj4 ,! filt]s are #ah 9 numb]1 & ea* has an effective area ( #a4hi1 or #cd acres 9 all4 ,!y are plann$ to filt] at a rate ( #a4fj million gallons p] acre daily1 :i* ) #af filt]s 9 use gives a daily quantity ( #dh1jjj1jjj gallons z ! pres5t limit ( ! works4 ,! sides ( ! filt]s are embankm5ts ) #a3b slopes4 ,bo? sides & bottoms h #bj in*es ( pack$ clay1 above :i* are #d in*es ( puddle1 support+ a brick pavem5t laid 9 cem5t4 ,! bricks are laid flat on ! bottom1 b edge-wise on ! sides :]e !y w come 9 contact ) ice4 ,! ma9 efflu5t-dra9 has a cross-section = ! :ole l5g? ( ! filt] ( #d4gc squ>e feet1 or #a_/agjjj ( ! area ( ! filt]2 & ev5 at ! l[ rate ( filtration propos$1 ! velocity 9 ! dra9 w rea* #j4ig foot4 ,! dra9 has brick sides1 #a4hj feet high1 cov]$ ) granite slabs4 ,! lat]al dra9s are all ( brick ) num]\s l>ge op5+s = admission ( wat]4 ,!y are n v5tilat$1 & ,i am unable to le>n t any bad results foll[ ?is omission4 ,! fill+ ( ! filt]s consi/s ( #b feet ( gravel1 ! top be+ ( c\rse f9] ?an ! bottom lay]s1 above :i* are #dj in*es ( s&1 :i* are to be r$uc$ to #bd in*es by scrap+ be=e be+ refill$4 ,! wat] ov] ! s&1 :5 ! latt] is ( full dep?1 is #dc in*es deep1 & w be increas$ to #ei in*es ) ! m9imum s&-?ickness4 ,! app>atus = regulat+ ! rate ( filtration 0 describ$ page #eb4 ,! co/ ( ! entire plant1 includ+ #cd acres effective filt]-surface1 #dj acres ( s$im5tation-bas9s1 ov] #b miles ( #h-a_/b-;foot conduit1 pump+-ma*9]y1 s&-wa%+ app>atus1 laboratory1 etc41 0 ab\t #i1ejj1jjj m>ks1 or #b1bhj1jjj4 ,?is all reckon$ on ! effective filt] area is #fg1jjj p] acre1 or #c4hj p] head = a population ( #fjj1jjj4 ,! dea?-rate s9ce ! introduction ( filt]$ wat] has be5 l[] ?an ev] be=e 9 ! hi/ory ( ! city1 b z x is ?\ght t o!r conditions may help to ?is result1 no conclusions are z yet drawn4 ,,dea?s ,,9 ,,hamburg ,,f ,,all ,,causes1 ,,& ,,f ,,typhoid ,,fev]1 ,,be=e ,,& ,,aft] ,,! ,,introduction ,,( ,,filt]s4 ---------------------------------------- ---------------- ,dea?s f,dea?s f all ,causes ,typhoid ,ye>4 p] #ajjj ,fev] p] ,liv+4 #ajj1jjj ,liv+4 ---------------------------------------- ---------------- #ahhj #bd4i #bf #ahha #bd4a #cj #ahhb #bc4g #bg #ahhc #be4b #be #ahhd #be4a #bf #ahhe #be4c #db #ahhf #bi4j #ga #ahhg #bf4f #hh #ahhh #bd4e #ed #ahhi #bc4e #dc #ahij #bb4j #bg #ahia #bc4d #bd #ahib #da4a #cd ,*ol]a ye>4 #ahic #bj4b #ah ,filt]$ wat] f ,may #bh4 #ahid #ag4i #g #ahie #ai4j #aa #ahif #ag4c #f #ahig #ag4j #g #ahih #ag4e #e ,av]age = #e ye>s1 exclud+ *ol]a ye>1 be=e filtration1 #ahhg to #ahia #bd4j #dg4b ,av]age = #e ye>s ) filtration1 #ahid to #ahih #ag4g #g4b ---------------------------------------- ---------------- ,,app5dix ,,ix4 ,,notes ,,on ,,"s ,,o!r ,,european ,,wat]-,,supplies4 ,am/]dam4--,! wat] is d]iv$ f op5 canals 9 ! dunes4 ,^! canals h an aggregate l5g? ( ab\t #ae miles1 & dra9 ab\t #fbjj acres4 ,! wat]1 z x ent]s ! canals f ! f9e dune-s&1 conta9s iron1 b ?is is oxidiz$ & deposit$ 9 ! canals4 ,! wat] aft] collection is filt]$4 ,x has be5 sugge/$ t by us+ cov]$ dra9s in/ead ( op5 canals = collect+ ! wat]1 ! filtration w\ld be unnecess>y2 b1 on ! o!r h&1 ! co/ ( build+ & ma9ta9+ cov]$ dra9s 9 ! v f9e s& w\ld be mu* great] ?an t ( ! canals1 & x is believ$1 also1 t ! wat] s collect$ w\ld conta9 iron1 ! removal ( :i* might prove z exp5sive z ! pres5t filtration4 ,9 #ahhg filt]s 7 built to take wat] f ! riv] ,ve*t1 b ! city has refus$ to all[ ! ,engli% company :i* owns ! wat]-works to sell ?is wat] = dome/ic purposes1 & x is only us$ = public & manufactur+ purposes1 only a fraction ( ! available supply be+ requir$4 ,leyd51 ! ,hague1 & "s o!r ,dut* cities h supplies l ! dune supply ( ,am/]dam1 & !y are inv>iably filt]$4 ,antw]p is also suppli$ by an ,engli% company4 ,! raw wat] is drawn f a small tidal riv]1 :i* at times is pollut$ by ! sewage ( ,brussels4 ,x is treat$ by metallic iron 9 ,&]son revolv] purifi]s1 & is aft]w>d filt]$ at a r l[ av]age rate4 ,! hygi5ic results are closely wat*$ by ! city au?orities1 & are said to be satisfactory4 ,rott]dam4--,! raw wat] is drawn f ! ,maas1 z ! ,dut* call ! ma9 /ream ( ! ,rh9e aft] x crosses _! bord]4 ,! population ^u ! riv] & its tribut>ies 9 ,switz]l&1 ,g]many1 ,holl&1 ,france1 & ,belgium is v great2 b ! fl[ is also great1 & ! l[ wat] fl[ is exceptionally l>ge 9 proportion to ! av]age fl[1 on acc\nt ( ! melt+ sn[ 9 summ] 9 ,switz]l&1 :]e x has its orig94 ,! orig9al filt]s _h wood5 "u-dra9s1 & !re 0 con/ant tr\ble ) cr5o?rix until ! filt]s 7 recon/ruct$ )\t wood1 s9ce :i* "t !re has be5 no f>!r tr\ble4 ,! pres5t filt]s are l>ge & well manag$4 ,!re is ample prelim9>y s$im5tation4 ,s*i$am4--,! filt]s at ,s*i$am are comp>atively small1 b are ( unusual int]e/ on acc\nt ( ! way 9 :i* !y are op]at$4 ,! intake is f ! ,maas j bel[ ,rott]dam4 ,! city 0 unable to raise ! money to seek a m di/ant s\rce ( supply1 & ! eng9e]1 ,h4 ,p4 ,n4 ,halb]tsma1 0 unwill+ to recomm5d a supply f s d\btful a s\rce )\t m ?or\gh treatm5t ?an simple s&-filtration 0 !n ?\ght to be4 ,! plan adopt$ is to filt] ! supply aft] prelim9>y s$im5tation ?r\gh two filt]s ( #j4bfe acre ea*1 & ! result+ efflu5t is !n pass$ ?r\gh ?ree o!r filt]s ( ! same size4 ,riv] s& is us$ = ! fir/1 & ! v f9e dune s& = ! second filtration4 ,! co/ bo? ( con/ruction & op]ation 0 satisfactory to ! city1 & mu* bel[ t ( any o!r available s\rce2 & ! hygi5ic results h be5 equally satisfactory1 not)/&+ ! unfavorable position ( ! intake4 ,magdeburg4--,! supply is drawn f ! ,elbe1 & is filt]$ ?r\gh vault$ filt]s aft] prelim9>y s$im5tation4 ,! pollution ( ! riv] is consid]able1 al?\gh less ?an at ,altona or ev5 at ,hamburg4 ,! city has be5 tr\bl$ at times by enorm\s dis*>ges ( salt solution f salt-works f>!r up1 :i* at extreme l[ wat] h sometimes r5d]$ ! :ole riv] bracki% & unpleasant to ! ta/e2 b arrangem5ts h n[ be5 made :i*1 x is hop$1 w prev5t ! recurr5ce ( ?is tr\ble4 ,breslau is suppli$ ) filt]$ wat] f ! riv] ,od]1 :i* has a wat]%$ ( #hbjj squ>e miles above ! intake1 & is pollut$ by ! sewage f cities ) an aggregate population ( ab\t #bjj1jjj1 "s ( :i* are 9 ,galicia1 :]e *ol]a is (t5 preval5t4 ,9 rec5t ye>s ! city has be5 free f *ol]a1 & f m ?an a v limit$ numb] ( typhoid-fev] cases2 b ! pollution is s great z to cause "s anxiety1 not)/&+ ! favorable record ( ! filt]s1 & !re is talk ( ! desirability ( secur+ ano!r supply4 ,until #ahic !re 7 f\r filt]-b$s1 ) areas ( #a4jc acres ea*1 & n cov]$4 ,9 #ahic a fif? b$ 0 add$4 ,?is is cov]$ by vault+ & is divid$ into f\r sections1 :i* are sep>ately op]at$1 s t x is really f\r b$s ( #j4be acre ea*4 ,! vault+ is concrete ar*es1 support$ by /eel ,i beams 9 "o direction4 ,budape/4--,a great v>iety ( tempor>y wat]-supplies h at diff]5t times be5 us$ by ?is rapidly gr[+ city4 ,! filt]s :i* = "s ye>s h suppli$ a portion ( ! supply h n be5 altoge!r satisfactory2 b p]haps ?is 0 due to lack ( prelim9>y s$im5tation = ! extremely turbid ,danube wat]1 & also to inadequate filt]-area4 ,! city is rapidly build+ & ext5d+ works = a supply ( gr\nd-wat]1 & 9 #ahid ! filt]s 7 only us$ z 0 necess>y to supplem5t ?is supply1 & x 0 hop$ t en\gh well-wat] w\ld be obta9$ to all[ ! filt]s to be ab&on$ 9 ! ne> future4 ,! ,danube above ! intake receives ! sewage ( ,vi5na & innum]able small] cities1 b ! volume ( ! riv] is v great comp>$ to o!r ,european /reams1 s t ! relative pollution is n s great z 9 _m o!r places4 ,zri*4--,! raw wat] is drawn by ! city f ! ,lake ( ,zri* ne> its outlet1 & b a few hundr$ feet f ! he>t ( ! city4 ,al?\gh no public sew]s dis*>ge into ! lake1 !re is "s pollution f boats & ba!rs & o!r s\rces1 &1 judg+ by ! numb] ( bact]ia 9 ! raw wat]1 ?is pollution is increas+4 ,! raw wat] is extremely free f s$im5t1 & ! filt]s only become clogg$ v sl[ly4 ,! rate ( filtration is high1 habitually rea*+ #g1jjj1jjj gallons p] acre daily2 b1 ) ! cle> lake wat] & long p]iods betwe5 scrap+s1 ! results are excell5t ev5 at ?is rate4 ,! filt]s are all cov]$ ) concrete gro9$ ar*es4 ,filtration 0 comm5c$ 9 #ahhf1 & 0 foll[$ by a %>p decl9e 9 ! am\nt ( typhoid fev]1 :i*1 up to t "t1 _h be5 r increas+2 = ! six ye>s be=e ! *ange !re 7 sixty-n9e dea?s f ?is cause annually p] #ajj1jjj liv+1 & = ! six ye>s aft] only t51 or "o sev5? z _m2 & ?is r$uction is attribut$ by ! local au?orities to ! filtration4#fd ,/4 ,pet]sburg4--,! supply is drawn f ! ,neva ,riv] by an ,engli% company1 & is filt]$ ?r\gh vault$ filt]s at a v high rate4 ,w>saw4--,! supply is drawn f ! ,wei*sel ,riv] by ! city1 & is filt]$ ?r\gh vault$ filt]s aft] prelim9>y s$im5tation at a rate nev] exce$+ #b1egj1jjj gallons p] acre daily4 ,,! ,,use ,,( ,,unfilt]$ ,,surface-,,wat]s4 ,! use ( surface-wat] )\t filtration 9 ,europe is comp>atively limit$4 ,9 ,g]many ?is use is n[ prohibit$ by ! ,imp]ial ,bo>d ( ,heal?4 ,9 ,great ,brita91 ,glasg[ draws its supply unfilt]$ f ,lo* ,katr9e2 & ,man*e/] & "s o!r t[ns use unfilt]$ wat]s f lakes or imp\nd+ res]voirs ! wat]%$s ( :i* are entirely free f population4 ,! be/ ,engli% practice1 h[ev]1 z 9 ,g]many1 requires ! filtration ( su* wat]s ev5 if !y are n kn[n to receive sewage1 & ! unpollut$ supplies ( ,liv]pool1 ,brad=d1 ,dubl91 & _m o!r cities are filt]$ be=e use4 ,,! ,,use ,,( ,,gr\nd-,,wat]4#fe ,gr\nd-wat]s are ext5sively us$ 9 ,europe1 & app>5tly 9 "s localities ! geological =mations are unusually favorable to ?is k9d ( supply4 ,p>is d]ives all ! wat] x n[ uses = dome/ic purposes f spr+s1 b has a supplem5t>y supply f ! riv] = o!r purposes4 ,vi5na & ,muni* also obta9 _! entire supplies f spr+s1 :ile ,budape/1 ,cologne1 ,leipzig1 ,dresd51 ,frankfurt1 _m ( ! great ,fr5* cities1 ,brussels1 a "p ( ,london1 & _m o!r ,engli% cities d]ive _! supplies f wells or filt]-gall]ies1 & among ! small] cities all ov] ,europe gr\nd-wat] supplies are m num]\s ?an o!r k9ds4 ,,app5dix ,x4 ,,lit]ature ,,( ,,filtration4 ,! foll[+ is a li/ ( a numb] ( articles on filtration4 ,! li/ is n complete1 b x is believ$ t x conta9s ! great] "p ( articles ^u sl[ s&-filtration1 & t x w prove s]viceable to ^? :o wi% to /udy ! subject m 9 detail4 ,,anklamm4 ,glas]s ,annal51 #ahhf1 p4 #dh4 ,a description ( ! ,tegel filt]s at ,b]l91 ) excell5t plans4 ,,bak]4 ,eng9e]+ ,news4 ,wat] purification 9 ,am]ica3 a s]ies ( descriptions ( filt]s1 z foll[s3 ,aug4 #c1 #ahic1 ,lawr5ce filt] & description ( app>atus ( scre5+ s& & gravel2 ,apr4 #bf1 #ahid1 filt] at ,nantucket1 ,mass42 ,june #g1 #ahid1 filt]s at ,ilion1 ,n4 ,y41 plans2 ,june #ad1 #ahid1 filt]s at ,hudson1 ,n4 ,y42 ,july #ab1 #ahid1 filt]s at ,zri*1 ,switz]l&1 plans2 ,aug4 #bc1 #ahid1 filt]s at ,mt4 ,v]non1 ,n4 ,y41 plans4 ,,b]ts*+]4 ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahhi1 p4 #aabf4 ,a record ( exp]im5ts made at ,zri* ^u ! effect ( rate ( filtration1 scrap+1 & ! influ5ce ( vault+4 ,rate & vault+ 7 f\nd to be )\t effect1 b poor] results foll[$ scrap+4 ,! numb]s ( bact]ia 9 ! lake-wat] 7 too l[ to all[ conclusive results4 ---- ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahia1 p4 #fhd4 ,a f>!r acc\nt ( ! ,zri* results1 ) full analyses & a criticism ( ,frnkel & ,piefke's exp]im5ts4 ,,bolton4 ,pamphlet1 #ahhd4 ,descriptions & /ati/ics ( ,london filt]s4 ,b,,tt*] & ,,ohnesorge4 ,zeits*rift fr ,bauwes51 #ahgf1 p4 #cdc4 ,a description ( ! ,brem5 works1 ) full plans4 ,,burton4 ,wat]-supply ( ,t[ns4 ,london1 #ahid4 ,pages #id-aae are ^u filtration & m5tion a novel me?od ( regulat+ ! rate4 ,,codd4 ,eng9e]+ ,news1 ,apr4 #bf1 #ahid4 ,a description ( a filt] at ,nantucket1 ,mass4 ,,cram]4 ,c5tralblatt fr ,bauwes51 #ahhf1 p4 #db4 ,a description ( filt]s built at ,brieg1 ,g]many4 ,,crook4 ,london ,wat]-supply4 ,london1 #ahhc4 ,,delbruck4 ,allgeme9e ,bauzeitung1 #ahec1 p4 #ajc4 ,a g5]al article on filtration2 p>ticul>ly valuable = notices ( e>ly attempts at filtration & ( ! use ( alum4 ,deuts*e ,v]e9 von ,gas- und ,wass]fa*mnn]4 ,/5ographic reports ( ! proce$+s ( ?is society are pr9t$ regul>ly 9 ! ,j\rnal fr ,gas- und ,wass]v]sorgung1 & ! discussions ( pap]s are (t5 mo/ int]e/+4 ,,dr[n4 ,j\rnal ,association ,eng4 ,societies1 #ahij1 p4 #cef4 ,filtration ( natural wat]s4 ,,fis*]4 ,vi]teljahress*rift fr ,gesundheitspflege1 #ahia1 p4 #hb4 ,discussion ( pap]s on wat]-filtration4 ,,fr,,nkel4 ,vi]teljahress*rift fr ,gesundheitspflege1 #ahia1 p4 #ch4 ,on filt]s = city wat]-works4 ,,fr,,nkel & ,,piefke4 ,zeits*rift fr ,hygi5e1 #ahia1 p4 #ch1 ,lei/ung5 d] ,s&filt]n4 ,e4 ,,frankl&4 ,report 9 reg>d to ! ,london filt]s = #ahic 9 ! ,annual ,summ>y ( ,bir?s1 ,dea?s1 & ,causes ( ,dea? 9 ,london & ,o!r ,great ,t[ns1 #ahic4 ,publi%$ by au?ority ( ! ,regi/r>-,g5]al4 ,p4 ,,frankl&4 ,proc4 ,royal ,society1 #ahhe1 p4 #cgi4 ,! removal ( micro-organisms f wat]4 ---- ,proce$+s ,in/4 ,civil ,eng9e]s1 #ahhf1 lxxxv4 p4 #aig4 ,wat]-purification2 its biological & *emical basis4 ---- ,trans4 ( ,sanit>y ,in/itute ( ,great ,brita91 #ahhf4 ,filtration ( wat] = t[n supply4 ,,fr,,hl+4 ,h&bu* d] ,+5ieurwiss5s*aft51 vol4 ii4 ,*apt] on wat]-filtration gives g5]al acc\nt ( filtration1 ) details ( ,knigsb]g filt]s built by ! au?or & n else:]e publi%$4 ,,full]4 ,report ,mass4 ,/ate ,bo>d ( ,heal?1 #ahib1 p4 #ddi4 ,report ,mass4 ,/ate ,bo>d ( ,heal?1 #ahic1 p4 #dec4 ,acc\nts ( ! ,lawr5ce exp]im5ts ^u wat]-filtration = #ahib & #ahic4 ---- ,am]ican ,public ,heal? ,association1 #ahic1 p4 #aeb4 ,on ! removal ( pa?og5ic bact]ia f wat] by s& filtration4 ---- ,am]ican ,public ,heal? ,association1 #ahid1 p4 #fd4 ,s& filtration ( wat] ) special ref]5ce to results obta9$ at ,lawr5ce1 ,mass4 ,,gill4 ,deuts*e ,bauzeitung1 #ahha1 p4 #efg4 ,on ,am]ican rapid filt]s4 ,! au?or %[s t !y are n to be ?\ght ( = ,b]l91 z !y w\ld be m exp5sive z well z probably less effici5t ?an ! usual proc$ure4 ---- ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahib1 p4 #eif4 ,a g5]al acc\nt ( ! ext5sion ( ! ,b]l9 filt]s at ,mggel4 ,no draw+s4 ,,grahn4 ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahgg1 p4 #edc4 ,on ! filtration ( riv]-wat]s4 ---- ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahij1 p4 #eaa4 ,filt]s = city wat]-works4 ---- ,vi]teljahress*rift fr ,gesund%eitpflege1 #ahia1 p4 #gf4 ,discussion ( pap]s pres5t$ on filtration4 ---- ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahid1 p4 #ahe4 ,a hi/ory ( ! 8,rules = ,wat]-filtration0 7,app5dix ,i71 ) "s discussion ( !m4 ,,grahn & ,,mey]4 ,reiseb]i*te b] kn/li*e c5tral ,s&filtration4 ,hamburg1 #ahgf4 ,an acc\nt ( ! obs]vations ( ! au?ors 9 num]\s cities1 especially 9 ,engl&4 ,,gr5zm]4 ,c5tralblatt d] ,bauv]waltung1 #ahhh1 p4 #adh4 ,a description ( new filt]s at ,am/]dam1 ) plans4 ,,grub]4 ,c5tralblatt fr ,bakt]iologie1 #ahic1 p4 #dhh4 ,sali5t po9ts 9 judg+ ( ! "w ( s&-filt]s4 ,,halb]tsma4 ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahib1 p4 #dc4 ,filt]-works 9 ,holl&4 ,gives s&1 gravel1 & wat] ?ickness1 ) diagrams4 ---- ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahib1 p4 #fhf4 ,description ( filt]s built by ! au?or at ,leeuw>d51 ,holl&1 ) plans4 ,,h>t4 ,proce$+s ,in/4 ( ,civil ,eng9e]s1 #ahij1 c4 p4 #bag4 ,description ( filt]s at ,%anghai4 ,,haus54 ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahib1 p4 #ccb4 ,an acc\nt ( exp]im5ts made = "o ye> ) ?ree #af-;in* filt]s at ,hels+=s1 ,f9l&1 ) weekly analyses ( efflu5ts4 ,,haz54 ,report ( ,mass4 ,/ate ,bo>d ( ,heal?1 #ahia1 p4 #fja4 ,exp]im5ts ^u ! filtration ( wat]4 ---- ,report ( ,mass4 ,/ate ,bo>d ( ,heal?1 #ahib1 p4 #eci4 ,physical prop]ties ( s&s & gravels ) ref]5ce to _! use 9 filtration4 7,app5dix ,,iii47 ,,hunt]4 ,eng9e]+1 #ahib1 vol4 #ec1 p4 #fba4 ,description ( au?or's s&-wa%+ app>atus4 ,,kirkwood4 ,filtration ( ,riv]-wat]s4 ,new ,york1 #ahfi4 ,a report ^u ,european filt]s = ! ,/4 ,l\is ,wat] ,bo>d 9 #ahff4 ,conta9s a full acc\nt ( ?irte5 filtration-works visit$ by ! au?or1 & ( a numb] ( filt]-gall]ies1 ) a project = filt]s = ,/4 ,l\is4 ,?is project 0 nev] execut$1 b ! report is a wond]ful "w :i* appe>$ a g5]ation be=e ! ,am]ican public 0 able to appreciate x4 ,x 0 translat$ into ,g]man1 & ! ,g]man edition 0 widely circulat$ & kn[n4 ,,ko*4 ,zeits*rift fr ,hygi5e1 #ahic4 ,wat]-filtration & ,*ol]a3 a discussion ( ! ,hamburg epidemic ( #ahib 9 ref]5ce to ! effect ( filtration4 ,,kr,,hnke4 ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahic1 p4 #eac4 ,an acc\nt ( exp]im5ts made at ,hamburg1 z a result ( :i* ! au?or recomm5ds ! addition ( cupr\s *loride to ! wat] be=e filtration to secure great] bact]ial effici5cy4 ,k,,mmel4 ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahgg1 p4 #deb4 ,op]ation ( ! ,altona filt]s1 ) analyses4 ---- ,vi]teljahress*rift fr ,gesundheitspflege1 #ahha1 p4 #ib4 ,! wat]-works ( ! city ( ,altona4 ---- ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahhg1 p4 #ebb4 ,an article oppos+ ! use ( rapid filt]s 7,david's process74 ---- ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahij1 p4 #eca4 ,a criticism ( ,frnkel & ,piefke's results1 ) "s /ati/ics ( ,g]man & ,engli% filt]s4 7,! ,engli% results are tak5 )\t cr$it f ,kirkwood47 ---- ,vi]teljahress*rift fr ,gesundheitspflege1 #ahia1 p4 #hg4 ,discussion ( pap]s on filtration1 ) "s /ati/ics4 ---- ,vi]teljahress*rift fr ,gesundheitspflege1 #ahib1 p4 #che4 ,! epidemic ( typhoid-fev] 9 ,altona 9 #ahia4 ---- ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahic1 p4 #afa4 ,results ( exp]im5ts ^u filtration made at ,altona1 & bact]ial results ( ! ,altona filt]s 9 connection ) typhoid dea?-rates4 ---- ,trans4 ,am4 ,society ( ,civil ,eng9e]s1 #ahic1 xxx4 p4 #ccj4 ,que/ions ( wat]-filtration4 ,,leslie4 ,trans4 ,in/4 ,civil ,eng9e]s1 #ahhc1 lxxiv4 p4 #aaj4 ,a %ort description ( filt]s at ,ed9burgh4 ,,l9dley4 ,a report = ! commission]s ( ! ,p>is ,exposition ( #ahhi ^u ! purification ( riv]-wat]s1 & publi%$ 9 ,fr5* or ,g]man 9 a numb] ( j\rnals1 among !m ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahij1 p4 #eja4 ,?is is a mo/ satisfactory discussion ( ! conditions :i* mod]n exp]i5ce has %[n to be ess5tial to successful filtration4 ,,mason4 ,eng9e]+ ,news1 ,dec4 #g1 #ahic4 ,filt]s at ,/uttg>t1 ,g]many1 ) plans4 ,,mey] & ,,samuelson4 ,deuts*e ,bauzeitung1 #ahha1 p4 #cdj4 ,project = filt]s = ,hamburg1 ) diagrams4 ,except 9 detail1 ?is project is ! same z t execut$ twelve ye>s lat]4 ,,mey]4 ,deuts*e ,bauzeitung1 #ahib1 p4 #eai4 ,description ( ! propos$ ,hamburg filt]s1 ) diagrams4 ---- ,! ,wat]-works ( ,hamburg4 ,a pap] pres5t$ to ! ,int]national ,heal? ,congress at ,rome1 ,m>* #ahid1 & publi%$ z a monograph4 ,x conta9s a full description ( ! filt]s z built1 ) draw+s & views 9 great] detail ?an ! prec$+ pap]4 ,,mills4 ,special ,report ,mass4 ,/ate ,bo>d ( ,heal? on ! ,purification ( ,sewage & ,wat]1 #ahij1 p4 #fja4 ,an acc\nt ( ! ,lawr5ce exp]im5ts1 #ahhh-ahij4 ---- ,report ,mass4 ,/ate ,bo>d ( ,heal?1 #ahic1 p4 #edc4 ,! ,filt] ( ! ,wat]-supply ( ! ,city ( ,lawr5ce & its ,results4 ---- ,trans4 ,am4 ,society ( ,civil ,eng9e]s1 #ahic1 xxx4 p4 #cej4 ,purification ( ,sewage & ,wat] by ,filtration4 ,,neville4 ,eng9e]+1 #ahgh1 xxvi4 p4 #cbd4 ,a description ( ! ,dubl9 filt]s1 ) plans4 ,,ni*ols4 ,report ,mass4 ,/ate ,bo>d ( ,heal?1 #ahgh1 p4 #acg4 ,! filtration ( potable wat]4 ,,oe/]4 ,gesundheits-,+5ieur1 #ahic1 p4 #eje4 ,:at is ! ,rate ( ,filtration8 ,a purely !oretical discussion4 ,,orange4 ,trans4 ,in/4 ,civil ,eng9e]s1 #ahij1 c4 p4 #bfh4 ,filt]s at ,hong ,kong4 ,,pfeff]4 ,deuts*e ,bauzeitung1 #ahhj1 p4 #cii4 ,a description ( filt]s at ,liegnitz1 ,g]many4 ,,piefke4 ,results ( ,natural & ,artificial ,filtration4 ,b]l91 #ahha4 ,pamphlet4 ---- ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahhg1 p4 #eie4 ,die ,pr9cipi5 d] ,re9wass]gew9nung v]mittel/ ,filtration4 ,a sket* ( ! !ory & practical application ( filtration4 ---- ,zeits*rift fr ,hygi5e1 #ahhi1 p4 #abh4 ,aphorism5 b] ,wass]v]sorgung4 ,a discussion ( ! !ory ( filtration1 ) a numb] ( exp]im5ts on ! ?ickness ( s&-lay]s1 etc4 ,,piefke4 ,vi]teljahress*rift fr ,gesundheitspflege1 #ahia1 p4 #ei4 ,on filt]s = city wat]-works4 ,,fr,,nkel & ,,piefke4 ,zeits*rift fr ,hygi5e1 #ahia1 p4 #ch4 ,lei/ung5 d] ,s&filt]n4 ,an acc\nt ( ! p>tial ob/ruction ( ! ,/ralau filt]s by ice1 & a typhoid epidemic :i* foll[$4 ,exp]im5ts 7 !n made ^u ! passage ( *ol]a & typhoid g]ms ?r\gh small filt]s4 ,,piefke4 ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahia1 p4 #bjh4 ,neue ,ermittelung5 b] ,s&filtration4 ,! above m5tion$ exp]im5ts be+ object$ to on c]ta9 gr\nds1 !y 7 repeat$ by ,piefke alone1 confirm+ ! previ\s obs]vations on ! passage ( bact]ia ?r\gh filt]s1 b "u o!r conditions4 ---- ,zeits*rift fr ,hygi5e1 #ahid1 p4 #aea1 b] ,betriebsfhrung von ,s&filt]n4 ,a full acc\nt ( ! op]ation ( ! ,/ralau filt]s 9 #ahic1 ) discussion ( ! effici5cy ( filtration1 etc4 ,,plagge ,,& ,,proskau]4 ,zeits*rift fr ,hygi5e1 #aa4 p4 #djc4 ,exam9ation ( wat] be=e & aft] filtration at ,b]l91 ) !ory ( filtration4 ,,re9cke4 ,b]i*t b] die ,m$ic9is*e ,/ati/ik des ,hamburgis*5 ,/aates fr #ahib4 ,conta9s a mo/ valuable discussion ( ! relations ( filtration to *ol]a1 typhoid fev]1 & di>rha1 ) num]\s tables & *>ts4 7,ab/ract 9 ,app5dix ,,ii47 ,,re9s*4 ,c5tralblatt fr ,bakt]iologie1 #ahie1 p4 #hha4 ,an acc\nt ( ! op]ation ( ! ,altona filt]s4 ,high numb]s ( bact]ia 9 ! efflu5ts h (t5 result$ f ! dis*>ge ( sludge f ! s$im5tation-bas9s onto ! filt]s1 due to ! int]f]5ce ( ice on ! action ( ! float+ outlet = ! bas9s1 & ?is1 r ?an ! direct effect ( cold1 is believ$ to be ! direct cause ( ! l[ w9t] effici5cy4 ,! au?or urges ! necessity ( a deep] s&-lay]s 9 no case less ?an #ah in*es ?ick4 ,,r5k4 ,gesundheits-,+5ieur1 #ahhf1 p4 #ed4 ---- b] die ,ziele d] kn/li*e ,wass]filtration4 ,,ruhlmann4 ,wo*5blatt fr ,baukunde1 #ahhg1 p4 #dji4 ,a description ( filt]s at ,zri*4 ,,salba*4 ,glas]'s ,annal51 #ahhb4 ,filt]s at ,gron+51 ,holl&1 built 9 #ahhj4 ,alum us$4 ,,samuelson4 ,translation ( ,kirkwood's 8,filtration ( ,riv]-wat]s0 into ,g]man1 ) additional notes especially on ! !ory ( filtration & ! s& to be employ$4 ,hamburg1 #ahgf4 ,,samuelson4 ,filtration & con/ant wat]-supply4 ,pamphlet4 ,hamburg1 #ahhb4 ---- ,j\rnal f4 ,gas- und ,wass]v]sorgung1 #ahib1 p4 #ffj4 ,a discussion ( ! be/ mat]ials & arrangem5t = s&-filt]s4 ,,s*metz54 ,deuts*e ,bauzeitung1 #ahgh1 p4 #cad4 ,notice & ext5d$ criticism ( ,samuelson's translation ( ,kirkwood4 ,,s$d54 ,j\r4 ,asso4 ,eng4 ,soc41 #ahhi1 p4 #dgg4 ,9 reg>d to ! s$im5tation ( riv]-wat]s4 ,,s$gwick4 ,new ,engl& ,wat]-works ,association1 #ahib1 p4 #ajc4 ,european me?ods ( ,filtration ) ,ref]5ce to ,am]ican ,ne$s4 ,,sokal4 ,wo*5s*rift d] /rei*5 ,+5ieur-,v]e91 #ahij1 p4 #chf4 ,a %ort description ( ! filt]s at ,/4 ,pet]sburg1 & a comp>ison ) ^? at ,w>saw4 ,,/urmh,,fel4 ,zeits*rift f4 ,bauwes51 #ahhj1 p4 #cd4 ,a description ( ! ,magdeburg filt]s1 ) plans4 ,,toml9son4 ,am]ican ,wat]-works ,association1 #ahhh4 ,a pap] on filt]s at ,bombay & else:]e4 ,,turn]4 ,proc4 ,in/4 ,civil ,eng9e]s1 #ahij1 c4 p4 #bhe4 ,filt]s at ,yokohama4 ,,van ,,d] ,,tak4 ,tijds*rift van de ,maats*app+ van ,b\wkunde1 #ahge7874 ,a description 79 ,dut*7 ( ! ,rott]dam wat]-works1 includ+ ! wood5 dra9s :i* caus$ ! tr\ble ) cr5o?rix1 & :i* h s9ce be5 remov$4 ,diagrams4 ,,van ,,ijssel/eyn4 ,tijds*rift van het ,kon9klijk ,in/ituut van ,+5ieurs1 #ahib-e1 p4 #agc4 ,a description ( ! new ,rott]dam filt]s1 ) full draw+s4 ,,veitmey]4 ,v]h&lung5 d4 polyt4 ,gesell4 zu ,b]l91 ,april1 #ahhj4 ,filtration & purification ( wat]4 ,,wolffh,,gel4 ,arbeit5 aus dem ,kais]li*e ,gesundheitsamt1 #ahhf1 p4 #a4 ,exam9ations ( ,b]l9 wat] = #ahhd-e1 ) rem>ks %[+ sup]ior bact]ial effici5cy ) op5 filt]s4 ---- ,j\rnal fr ,gas- u4 ,wass]v]sorgung1 #ahij1 p4 #eaf4 ,on ! bact]ial effici5cy ( ! ,b]l9 filt]s1 ) diagrams4 ,,zobel4 ,zeits*rift des ,v]e9s deuts*e ,+5ieure1 #ahhd1 p4 #ecg4 ,description ( filt]s at ,/uttg>t4 ,,o!r ,,lit]ature4 ,_m sci5tific & eng9e]+ j\rnals publi% f "t to "t %ort articles or notices on filtration :i* are n includ$ 9 ! above li/4 ,among su* j\rnals none gives m att5tion to filtration ?an ! ,j\rnal fr ,gasbeleu*tung und ,wass]v]sorgung1 :i* publi%es regul>ly reports ^u ! op]ation ( _m ,g]man filt]s1 & gives %ort notices ( new con/ruction4 ,! fir/ articles ^u filtration 9 ?is j\rnal 7 a s]ies ( descriptions ( ,g]man wat]-works 9 #ahgj-gc1 includ+ descriptions ( filt]s at ,altona1 ,brunswick1 ,lbeck1 etc4 ,/5ographic reports ( _m sci5tific meet+s h be5 publi%$1 p>ticul>ly s9ce #ahij1 & s9ce #ahib !re has be5 mu* discussion 9 reg>d to ! 8,rules = ,filtration0 giv5 9 ,app5dix ,i4 ,a ,report ( a ,royal ,commission to inquire into ! wat]-supply ( ! metropolis1 ) m9utes ( evid5ce1 app5dices1 & maps 7,london1 #ahic-d71 conta9s mu* valuable mat]ial 9 reg>d to filtration4 ,! mon?ly reports ( ! wat] exam9]1 & o!r pap]s publi%$ by ! ,local ,gov]nm5t ,bo>d1 ,london1 are (t5 ( int]e/4 ,! ,g]man 8,v]e9 von ,gas- u4 ,wass]fa*mnn]0 pr9ts )\t publi%+ a mo/ useful annual summ>y ( ,g]man wat]-works /ati/ics = di/ribution to memb]s4 ,_m ( ! /ati/ics giv5 9 ?is volume are f ?is s\rce4 ,description ( ! filt]s at ,worms 0 giv5 9 ! ,deuts*e ,bauzeitung1 #ahib1 p4 #ejh2 ( ! filt]s at ,liv]pool 9 ,eng9e]+1 #ahhi1 p4 #aeb1 & #ahib1 p4 #gci4 ,! latt] j\rnal also has giv5 a numb] ( descriptions ( filt]s built 9 v>i\s p>ts ( ! _w by ,engli% eng9e]s1 b1 except+ ! articles m5tion$ 9 ! above li/1 ! descriptions are n giv5 9 detail4 ,,m ,,rec5t ,,articles4 ,! foll[+ are a few ( ! m important articles :i* h appe>$ s9ce ! fir/ edition ( ?is book4 ,9 addition _m articles ( curr5t int]e/ h appe>$ 9 ! te*nical j\rnals1 p>ticul>ly 9 ! j\rnals m5tion$ above4 ,,cl>k4 ,reports ( ,mass4 ,/ate ,bo>d ( ,heal?1 #ahid to #ahig1 inclusive4 ,articles on ! filtration ( wat]1 giv+ acc\nts ( exp]im5ts at ! ,lawr5ce ,exp]im5t ,/ation1 & records ( ! op]ation ( ! ,lawr5ce city filt]4 ,^! exp]im5ts are direct$ pr9cipally to ! removal ( bact]ia f sewage-pollut$ wat]s4 ---- ,j\r4 ,new ,engl& ,wat] ,works ,assoc41 ,,xi41 p4 #bgg4 ,removal ( ,iron f ,gr\nd ,wat]s4 ,a description ( c]ta9 exp]im5ts4 ,,f[l]4 ,j\r4 ,new ,engl& ,wat] ,works ,assoc41 ,,xii41 p4 #bji4 ,! ,op]ation ( a ,sl[ ,s& ,filt]4 ,a mo/ helpful & ?or\gh description ( ! op]ation ( s& filt]s at ,p\ghkeepsie = a long p]iod ( ye>s4 ,,full]4 ,wat] ,purification at ,l\isville4 ,d4 ,van ,no/r& ,co41 #ahih4 ,a report ^u a s]ies ( mo/ exhau/ive exp]im5ts c>ri$ out at ,l\isville1 direct$ pr9cipally to ! cl>ification ( excessively muddy wat]s4 ,conta9s a full acc\nt ( me?ods ( coagulation1 & ( exp]im5ts ) ! electrical treatm5t ( wat]4 ---- ,report on ,wat] ,filtration at ,c9c9nati4 ,city docum5t1 #ahii4 ,acc\nt ( exp]im5ts ) s& filt]s1 ) & )\t coagulants1 & ) o!r processes appli$ to ! ,ohio ,riv] wat] at ,c9c9nati4 ,,gill4 ,filt]s at ,muggel4 ,proc4 ,in/itute ( ,civil ,eng9e]s1 #ahid-e2 vol4 #aai1 p4 #bcf4 ,a description ( ! new vault$ filt] plant design$ by ! au?or = ,b]l91 ,g]many4 ,plans & views4 ,,goetze4 ,j\rnal fr ,gasbeleu*tung und ,wass]v]sorgung1 #ahig1 p4 #afi4 ,selb/?tige ,wass]au/rittsregl] besond]s fr ,filt]4 ,a description ( ! automatic regulat+ device = filt]s us$ at ,brem54 ---- ,zeits*rift des ,v]e9es deuts*] ,+5ieure1 ,,xxx4 ,re9igung des ,tr9kwass]s 9 ,brem5 dur* mehrmalige ,s&filtration4 ,a description ( ! me?od ( d\ble filtration us$ at ,brem51 giv+ results obta9$ 9 full4 ,no draw+s4 ,,grahn4 ,j\rnal fr ,gasbeleu*tung und ,wass]v]sorgung1 #ahie4 ,wat] purification plant at ! city ( ,magdeburg4 ,a description ( ! old plant1 & ! *anges :i* h be5 made 9 x to increase its capacity1 & make x con=m to ! requirem5ts ( ! ,g]man (ficial in/ructions reg>d+ filtration4 ,_m illu/rations & plans4 ,,halb]tsma4 ,j\rnal fr ,gasbeleu*tung und ,wass]v]sorgung1 #ahif4 ,die ,resultate d] doppelt5 ,filtration zu ,s*i$am4 ,a description ( d\ble filtration at ,s*i$am1 ) ! bact]ial results = ! two ye>s1 #ahid & #ahie1 %[+ an av]age bact]ial effici5cy ( #ii4gf p] c5t4 ,,haz54 ,report to ,filtration ,commission1 ,pittsburgh4 ,city docum5t1 #ahii4 ,a description ( exp]im5ts ^u ! treatm5t ( ! ,allegh5y ,riv] wat] by s& & me*anical filt]s4 ---- ,ohio ,/ate ,bo>d ( ,heal? ,report1 #ahig1 p4 #aed4 ,report on ! ,me*anical ,filtration ( ! ,public ,wat] ,supply ( ,lora94 ,gives ! results ( a five-weeks te/ ( ! ,jewell me*anical filt]s at ,lora91 treat+ ,lake ,erie wat]4 ,,kemna4 ,! ,biology ( ,s& ,filtration4 ,read be=e ! annual conv5tion ( ! ,briti% ,association ( ,wat] ,works ,eng9e]s4 ,ab/ract 9 ,eng9e]+ ,news1 ,,xli41 p4 #dai4 ,describ+ organisms :i* develop 9 op5 s& filt]s1 bo? animal & vegetable1 & _! effects ^u ! process4 ,a q full acc\nt ( ! au?or's ext5d$ exp]i5ce1 & ! only pap] treat+ ?is subject4 ,,mag>4 ,j\rnal fr ,gasbeleu*tung und ,wass]v]sorgung1 #ahig1 p4 #d4 ,re9igungsbetrieb d] (f5] ,s&filt] des ,hamburg] ,filt]w]kes 9 ,fro/zeit54 ,a new me?od ( clean+ op5 filt]s 9 w9t] )\t ! removal ( ! ice4 ,,panwitz4 ,arbeit5 aus dem ,kais]li*5 ,gesundheitsamte1 ,,xiv41 p4 #aec4 ,die ,filtration von ,ob]fl*5wass] 9 d5 deuts*5 ,wass]w]k5 whr5d d] ,jahre #ahid bis #ahif4 ,a description ( ! filtration works 9 ,g]many1 & ! results obta9$ f !m1 p>ticul>ly f ! po9t ( view ( bact]ial effici5cy4 ,results are graphically %[n by a s]ies ( *>ts4 ,,reyn>d4 ,le ,gnie ,civil1 #ahif1 ,,xxviii41 p4 #cba4 ,purification ( wat] ) ! aid ( metallic iron4 ,describ+ ! works ( ! ,compagnie ,gnral des ,eaux = supply+ ! suburbs ( ,p>is ) filt]$ wat]1 ! capacity ( ! works be+ ov] #bc1jjj1jjj gallons daily4 ,,we/on4 ,rhode ,isl& ,/ate ,bo>d ( ,heal?1 #ahid4 ,report ( ! ,results ,obta9$ ) ,exp]im5tal ,filt]s at ! ,pattaconset ,pump+ ,/ation ( ! ,provid5ce ,wat] ,works4 ,relates p>ticul>ly to ! bact]ial purification obta9$ ) rapid filtration aid$ by sulphate ( alum9a4 ,^! 7 ! fir/ sy/ematic exp]im5ts made ) me*anical filt]s4 ,,:eel]4 ,j\rnal ( ! ,new ,engl& ,wat] ,works ,assoc41 ,,xi41 p4 #cja4 ,cov]$ ,s& ,filt] at ,a%l&1 ,wis4 ,a description ( ! cov]$ filt]s built by ! au?or at ,a%l& ,wis4 = ! purification ( ! bay wat]4 ,views & draw+s4 ,,app5dix ,,xi4 ,,! ,,albany ,,wat]-,,filtration ,,plant4 7,abridg$ f ,proce$+s ,am]ican ,society ( ,civil ,eng9e]s1 ,nov4 #ahii47 ,albany1 ,n4 ,y41 0 orig9ally suppli$ ) wat] by gravity f c]ta9 res]voirs on small /reams we/ & nor? ( ! city4 ,9 "t1 ) increas+ consumption1 ! supply obta9$ f ^! s\rces became inadequate1 & an additional supply f ! ,hudson ,riv] 0 introduc$4 ,! wat] 0 obta9$ f ! riv] ?r\gh a tunnel "u ! ,erie ,bas91 & a pump+-/ation 0 erect$ 9 ,quack5bu% ,/reet to pump x to res]voirs1 "o ( :i* s]v$ also z ! di/ribut+ po9t = "o ( ! gravity supplies4 ,! intake1 :i* 0 us$ fir/ 9 #ahgc1 drew wat] f ! riv] opposite ! he>t ( ! city4 ,9 rec5t ye>s1 ! am\nt ( wat] drawn f ?is s\rce has greatly exce$$ t obta9$ f ! gravity s\rces4 ,! ,hudson ,riv]1 at ! po9t ( intake1 has a dra9age area ( #hbdj squ>e miles4 ,( ?is1 #deda squ>e miles are tribut>y to ! ,hudson above ,troy1 #cdic are tribut>y to ! ,mohawk1 & #afh are tribut>y to ! ,hudson bel[ ! ,mohawk4 ,! m9imum fl[ may be e/imat$ at #afeg cubic feet p] second1 or #a1jfj1jjj1jjj gallons p] #bd h\rs1 or at lea/ fifty times ! maximum consumption4 ,! cities & l>g] t[ns ^u ! riv] above ! intake1 ) e/imat$ populations & di/ances1 are z foll[s3 ,,mo/ ,,important ,,cities1 ,,t[ns1 ,,& ,,villages ,,on ,,! ,,wat]%$ ,,( ,,! ,,hudson ,,above ,,albany4 ---------------------------------------- ----------------------- ,approximate ,population 9 ,place4 ,c\nty4 ,di/ance --------------------------- above #ahhj4 #ahij4 #aijj4 ,intake1 ,miles4 7,e/imat$47 ---------------------------------------- --------------------- ,troy ,r5ssela] #d #ef1gdg #fj1ief #fe1dgj ,wat]vliet ,albany #d #h1hbj #ab1ifg #ai1jdj ,gre5 ,isl&,r5ssela] #e #d1afj #d1dfc #d1ghh ,cohoes ,albany #h #ai1daf #bb1eji #bf1dej ,lans+burg ,r5ssela] #h #g1dcb #aj1eej #ad1ihj ,wat]=d ,s>atoga #i 7#a1hbb7 #a1hbb 7#a1hbb7 ,s*5ectady ,s*5ectady #bh #ac1fee #ai1jjb #bf1dej ,hoosic ,falls,r5ssela] #dd #d1ecj #g1jad #aj1hfj ,am/]dam ,montgom]y #dd #i1dff #ag1ccf #ca1gcj ,gl5s ,falls ,w>r5 #di #d1ijj #i1eji #ah1dej ,s>atoga ,s>atoga #ea #h1dba #aa1ige #ag1jaj ,spr+s ,john/[n ,fulton #ef #e1jac #g1gfh #ab1jdj ,glov]sville,fulton #eh #g1acc #ac1hfd #bf1icj ,nor? ,adams1 ,mass4 ,b]k%ire #fh #aj1aia #af1jgd #be1cdj ,adams1 ,mass4,b]k%ire #ge #e1eia #i1bac #ae1aha ,little ,falls,h]kim] #hb #f1iaj #h1ghc #aa1afj ,utica ,oneida #ajg #cc1iad #dd1jjg #eg1jij ,rome ,oneida #abg #ab1aid #ad1iia #ah1dcj #cb villages #eb1ebc #fa1hfi #gf1aid ---------------------------------------- --------------------- ,total1 n includ+ rural population #bgb1hch #ced1fgb #dgi1dae ,p] squ>e mile #cc #dc #ei ---------------------------------------- ----------------------- ,)\t ent]+ into a detail$ discussion1 x may be said t ! am\nt ( sewage1 ) ref]5ce to ! size ( ! riv] & ! volume ( fl[1 is a fraction less ?an t at ,lawr5ce1 ,mass41 :]e a filt]-plant has also be5 con/ruct$1 b ! pollution is mu* great] ?an t ( mo/ ,am]ican riv]s f :i* municipal wat]-supplies are tak54 ,! filtration-plant complet$ 9 #ahii takes ! wat] f a po9t ab\t two miles above ! old intake4 ,pumps lift ! wat] to ! s$im5tation-bas91 f :i* x fl[s to ! filt]s & !nce ?r\gh a conduit to ! pump+-/ation previ\sly us$4 ,,description ,,( ,,plant4 ,intake4--,! intake consi/s ( a simple concrete /ructure 9 ! =m ( a box1 hav+ an op5 top cov]$ ) rails #f in*es ap>t1 & connect$ bel[1 ?r\gh a #cf-;in* pipe1 ) a well 9 ! pump+-/ation4 ,be=e go+ to ! pumps ! wat] passes ?r\gh a scre5 ) b>s #b in*es ap>t1 s arrang$ z to be rak$ readily4 ,! rails ov] ! intake & ?is scre5 are int5d$ to /op matt]s :i* might ob/ruct ! passageways ( ! pumps1 b no attempt is made to /op fi%1 leaves1 or o!r float+ matt]s :i* may be 9 ! wat]4 ,! arrangem5t1 9 ?is respect1 is l t ( ! filt] at ,lawr5ce1 ,mass41 :]e ! raw wat] is n subject$ to close scre5+4 ,!re is room1 h[ev]1 to place f9] scre5s 9 ! pump-well1 %\ld !y be f\nd desirable4 ,illu/ration3 ,,hudson ,,riv] ,,ne> ,,intake ,,fig4 #a4 ,illu/ration3 ,,s$im5tation-,,bas91 ,,pump+-,,/ation1 ,,& ,,outlets4 ,illu/ration3 ,,s$im5tation-,,bas91 ,,an ,,outlet1 ,,& ,,laboratory4 ,to face page #bij4 ,pump+-/ation4--,! c5trifugal pumps h a gu>ante$ capacity ( #af1jjj1jjj gallons p] #bd h\rs aga9/ a lift ( #ah feet1 or #ab1jjj1jjj gallons p] #bd h\rs aga9/ a lift ( #bd feet4 ,! ord9>y pump+ at l[ wat] is aga9/ ! high] lift1 & "u ^! conditions ei!r pump c supply ! ord9>y consumption1 ! o!r pump be+ held 9 res]ve4 ,! pump+-/ation build+1 to a po9t above ! highe/ flood-level1 is ( massive concrete con/ruction1 )\t op5+s4 ,ne>ly all ! ma*9]y is necess>ily bel[ ?is level1 & 9 high wat] ! sluice-gates are clos$1 & ! ma*9]y is ?us protect$ f flood+4 ,! sup]/ructure is ( press$ brick1 ) granite trimm+s4 ,met] = ,raw ,wat]4--,^u leav+ ! pump+-/ation ! wat] passes ?r\gh a #cf-;in* ,v5turi met] hav+ a ?roat diamet] ( #ag in*es1 ! ?roat area be+ two n9?s ( ! area ( ! pipe4 ,! met] records ! quantity ( wat] pump$1 & is also arrang$ to %[ on gauges 9 ! pump+-/ation ! rate ( pump+4 ,a]ation4--,aft] leav+ ! met]1 ! wat] passes to ! s$im5tation-bas9 ?r\gh elev5 outlets4 ,^! outlets consi/ ( #ab-;in* pipes on end1 ! tops ( :i* are #d feet above ! nom9al fl[-l9e ( ! s$im5tation-bas94 ,ea* ( ^! outlet-pipes is pi]c$ ) #bif #c_/h-;in* holes ext5d+ f #j4e to #c4e feet bel[ ! top ( ! pipe4 ,^! holes are comput$ s t :5 #aa1jjj1jjj gallons ( wat] p] day are pump$ all ! wat] w pass ?r\gh ! holes1 ! wat] 9 ! pipes /&+ flu% ) ! tops4 ,! wat] is ?us ?r[n out 9 #cbef small /reams1 & becomes a]at$4 ,:5 m ?an ! above am\nt is pump$1 ! excess fl[s ov] ! tops ( ! outlet-pipes 9 ?9 %eets1 :i* are brok5 by ! jets4 ,illu/ration3 ,,g5]al ,,plan ,,fig4 #b4 ,reg>d+ ! necessity = a]ation1 no obs]vations h be5 tak5 ^u ! ,hudson ,riv]1 b1 judg+ f exp]i5ce ) ! ,m]rimac at ,lawr5ce1 :]e ! conditions are 9 _m respects simil>1 ! wat] is at all times m or less a]at$1 &1 = ! great] "p ( ! ye>1 x is ne>ly saturat$ ) oxyg51 & a]ation is n necess>y4 ,dur+ l[ wat] 9 summ]1 h[ev]1 !re is mu* less oxyg5 9 ! wat]1 & at ^! times a]ation is a di/9ct advantage4 ,fur!r1 ! riv]-wat] w (t5 h a slight odor1 & a]ation w t5d to remove x4 ,! outlets are arrang$ s t !y c be remov$ readily 9 w9t] if !y are n f\nd necess>y at t season4 ,s$im5tation-bas94--,! s$im5tation-bas9 has an area ( #e acres & is #i feet deep4 ,to ! ov]fl[ x has a capacity ( #ad1fjj1jjj gallons1 & to ! fl[-l9e ( ! filt]s #h1ijj1jjj gallons4 ,!re is ?us a res]ve capacity ( #e1gjj1jjj gallons betwe5 ^! limits1 & ?is am\nt c be drawn ^u1 )\t inconv5i5ce1 = ma9ta9+ ! filt]s 9 s]vice :ile ! pumps are %ut d[n4 ,?is all[s a fre$om 9 ! op]ation ( ! pumps :i* w\ld n exi/ ) ! wat] suppli$ direct to ! filt]s4 ,! wat] ent]s ! s$im5tation-bas9 f elev5 inlets along "o side1 & is )drawn f elev5 outlets directly opposite4 ,! inlets & a]at+ devices describ$ previ\sly br+ ! wat] into ! bas9 )\t curr5t & ev5ly di/ribut$ along "o side4 ,bo? inlets & outlets are controll$ by gates1 s t any irregul>ities 9 di/ribution c be avoid$4 ,! concrete floor ( ! s$im5tation-bas9 is built ) ev5 slopes f ! toe ( ea* embankm5t to a sump1 ! heights ( ^! slopes be+ #a foot1 :atev] _! l5g?s4 ,! sump is connect$ ) a #bd-;in* pipe lead+ to a l>ge manhole 9 :i* !re is a gate ?r\gh :i* wat] c be drawn to empty ! bas94 ,!re is an ov]fl[ f ! bas9 to ?is manhole :i* makes x impossible to fill ! bas9 above ! int5d$ level4 ,illu/ration3 ,,longitud9al ,,section ,,on a-b-c-d-e-f-g-h ,,filt] ,,b$s ,,plan ,,& ,,section ,,( ,,filt] ,,no4 #b ,,fig4 #c4 ,illu/ration3 ,,outside ,,wall1 ,,ready ,,= ,,concrete ,,back+4 ,illu/ration3 ,,s$im5tation-,,bas93 ,,%[+ ,,con/ruction ,,( ,,floor4 ,to face page #bid4 ,filt]s4--,! filt]s are ( masonry1 & are cov]$ to protect !m aga9/ ! w9t]s1 :i* are q sev]e 9 ,albany4 ,! pi]s1 cross-walls1 & l9+s ( ! outside walls1 entrances1 etc41 are ( vitrifi$ brick4 ,all o!r masonry is concrete4 ,! av]age dep? ( excavation = ! filt]s 0 #d feet1 & ! mat]ial at ! bottom 0 usually blue or yell[ clay4 ,9 "s places %ale 0 enc\nt]$4 ,9 "o place s(t clay 0 f\nd1 & !re ! f\ndations 7 made deep]4 ,! floors consi/$ ( inv]t$1 gro9$1 concrete ar*es1 arrang$ to di/ribute ! weight ( ! walls & vault+ ov] ! :ole area ( ! bottom4 ,! gro9$ ar*-vault+ is ( concrete ) a cle> span ( #aa feet #aa in*es1 a rise ( #b-a_/b feet1 & a ?ickness ( #f in*es at ! cr[n4 ,x 0 put 9 9 squ>es1 ! jo9ts be+ on ! cr[ns ( ! ar*es p>allel ) ! l9es ( ! pi]s1 & ea* pi] be+ ! c5tre ( "o squ>e4 ,! manholes are 9 alt]nate sections1 & are ( concrete1 built 9 /eel =ms ) ca/+s at ! tops1 securely jo9t$ to ! concrete4 ,above ! vault+ !re are #b feet ( e>? & soil1 grass$ on top4 ,! tops ( ! manholes are #f in*es above ! soil to prev5t ra9-wat] f ent]+ !m4 ,! dra9age ( ! soil is effect$ by a depression ( ! vault+ ov] ea* pi]1 p>tially fill$ ) gravel & s&1 f :i* wat] is remov$ by a #b-;in* tile-dra9 go+ d[n ! c5tre ( ! pi] & dis*>g+ ?r\gh its side j above ! top ( ! s& 9 ! filt]4 ,9 ord] to provide ready access to ea* filt]1 a "p ( ! vault+ ne> "o side is elevat$ & made cyl9drical 9 %ape1 mak+ an incl9$ runway f ! s&-level to a door ! ?re%old ( :i* is #f in*es above ! level ( ! ov]fl[4 ,illu/ration3 ,,filt] ,,b$s ,,section ,,( ,,filt]s ,,fig4 #d4 ,?is s&-run is provid$ ) p]man5t timb] runways & ) secure doors4 ,illu/ration3 ,section4 ,elevation4 ,,fig4 #e4--;,,entrance ,,to ,a ,,filt]4 ,! manholes ( ! filt]s are provid$ ) d\ble cov]s ( /eel plates to exclude ! cold4 ,! cov]s also exclude light4 ,:5 clean+ ! filt]s1 light c be admitt$ by remov+ ! cov]s4 ,supports = electric lights are plac$ 9 ! vault+1 s t ! filt]s c be light$ by electricity & ! "w ( clean+ c be done at night1 & 9 w9t] "u heavy sn[1 )\t remov+ ! cov]s4 ,! electric lights h n yet be5 in/all$4 ,! regulator-h\ses1 ! entrances to ! s&-runs1 & all expos$ "w are ( press$ brick ) ,mil=d granite trimm+s & slate ro(s4 ,! regulator-h\ses h d\ble walls & d\ble w9d[s & a tight ceil+ 9 ! ro(1 to make !m z w>m z possible & to avoid ! necessity ( artificial heat to prev5t freez+4 ,illu/ration3 ,,comput$ ,,frictional ,,resi/ance ,,( ,,dra9age ,,sy/em ,,( ,,"o ,,filt] ,,:5 ,,op]at+ ,,at ,a ,,rate ,,( #ajj ,m4,m4 ,,p] ,,h\r1 ,,equal ,,to #b1egj1jjj ,,gals4 ,,p] ,,acre ,,daily4 ,,/&>d ,,gravel ,,sections4 ,,fig4 #f4 ,illu/ration3 ,,plac+ ,,! ,,floor ,,( ,a ,,filt]4 ,illu/ration3 ,,build+ ,,! ,,brick ,,pi]s4 ,to face page #bih4 ,! ma9 und]dra9s = remov+ ! filt]$ wat] are ( vitrifi$ pipe surr\nd$ by concrete & are entirely bel[ ! floors ( ! filt]s4 ,connections ) ! ma9 dra9 are made ?r\gh ?irty-eight #f-;in* outlets 9 ea* filt]1 pass+ ?r\gh ! floor & connect$ ) #f-;in* lat]al dra9s runn+ ?r\gh ! :ole wid? ( ! filt]4 ,^! dra9s 7 made ) pipes hav+ "o side ( ! bell cut (f s t !y w\ld lie flat on ! floor & make conc5tric jo9ts1 )\t support & )\t hav+ to be w$g$4 ,!y 7 laid ) a space ( ab\t #a in* betwe5 ! b>rels1 leav+ a l>ge op5+ = ! admission ( wat] f ! gravel4 ,! und]dra9age sy/em is s design$ t1 :5 />t+ a filt] aft] clean+1 ! friction ( ! s& is ab\t #ej mm4 at a rate ( #c1jjj1jjj gallons p] acre daily1 & ! friction ( ! und]dra9age sy/em is e/imat$ at #aj mm4 ,?is v l[ friction1 :i* is necess>y1 is obta9$ by ! use ( ample sizes = ! und]dra9s & l[ velocities 9 !m4 ,9 ! outlet & measur+ devices mod]ate losses ( head are n objectionable1 & ! sizes ( ! pipes & connections are1 !re=e1 small] ?an ! ma9 und]dra9s4 ,! gravel surr\nd+ ! und]dra9s is ( ?ree grades4 ,! mat]ial 0 obta9$ f ! riv]-b$ by dr$g+1 & 0 ( ! same /ock z t us$ = prep>+ balla/ = ! concrete4 ,x 0 sep>at$ & clean$ by a special1 cyl9drical1 revolv+ scre54 ,! co>se/ grade ( gravel 0 t :i* w\ld n pass r\nd holes #a in* 9 diamet]1 & free f /ones m ?an ab\t #b in*es 9 diamet]4 ,at fir/ x 0 requir$ to pass a scre5 ) holes #b in*es 9 diamet]1 b ?is scre5 remov$ _m /ones :i* x 0 desir$ to reta91 & ! scre5 0 aft]w>d *ang$ to h holes #c in*es 9 diamet]4 ,! int]m$iate grades ( gravel pass$ ! #a-;in* holes1 & 7 reta9$ by a scre5 ) r\nd holes #c_/h in* 9 diamet]4 ,! f9e/ gravel pass$ ! above scre5s & 0 reta9$ by a scre5 ) r\nd holes #c_/af in* 9 diamet]4 ,! gravel 0 wa%$1 until free f s& & dirt1 by wat] play$ ^u x dur+ ! process ( scre5+1 & x 0 aft]w>d tak5 ov] scre5s 9 ! *utes1 :]e x 0 sep>at$ f ! dirty wat]1 &1 :5 necess>y1 fur!r quantities ( wat] 7 play$ ^u x at ^! po9ts4 ,illu/ration3 ,,inlet ,,to ,,filt] ,,b$4 ,,section ,,on ,m-,n-,o ,,regulator ,,*amb] ,,longitud9al ,,section ,,on ,a-,b-,c-,d ,,regulator ,,*amb] ,,section ,,on ,k-,l ,,filt] ,,b$s ,,inlet ,,valves ,,& ,,regulator ,,*amb] ,,inlet ,,to ,,filt] ,,b$ ,,sectional ,,plan ,,on ,p-,q ,,orifice ,,indicator ,,m>k] ,,details ,,( ,,app>atus ,,9 ,,regulator ,,h\se ,,regulator ,,*amb] ,,sectional ,,plan ,,on ,e-,f-,g-,h-,j ,,fig4 #g4 ,! av]age me*anical analyses ( ! ?ree grades ( gravel are %[n by ,fig4 #h4 ,_! effective sizes 7 #bc1 #h1 & #c mm4 respectively1 & = conv5i5ce !y are designat$ by ^! numb]s4 ,! av]age uni=mity coeffici5t = ea* grade 0 ab\t #a4h4 ,! #bc-mm4 gravel entirely surr\nd$ ! #f-;in* pipe-dra9s1 & 0 c>ri$ slightly above _! tops4 ,9 "s cases x 0 us$ to cov] ne>ly ! :ole ( ! floor1 b ?is 0 n insi/$ ^u4 ,! #h-mm4 gravel 0 obta9$ 9 l>g] quantity ?an ! o!r sizes1 & 0 us$ to fill all spaces up to a plane #b-a_/b in*es bel[ ! f9i%$ surface ( ! gravel1 ?is lay] be+ ab\t #b in*es ?ick ov] ! tops ( ! dra9s1 & some:at ?ick] else:]e4 ,! #c-mm4 gravel 0 !n appli$ 9 a lay] #b-a_/b in*es deep1 & ! surface levell$4 ,! prelim9>y e/imates ( co/ 7 bas$ ^u ! use ( filt]-s& f a bank ne> ! filt]-site4 ,fur!r exam9ation %[$ t ?is s& conta9$ a consid]able quantity ( lime1 & x 0 f\nd by exp]im5t ) a small filt] con/ruct$ = t purpose t ! use ( ?is s& w\ld h>d5 ! wat] by ab\t #b p>ts 9 #ajj1jjj1 & ! am\nt ( lime conta9$ 9 ! s&1 namely1 ab\t #g p] c5t1 0 suffici5t to cont9ue ?is h>d5+ action = a consid]able numb] ( ye>s4 ,?is 0 reg>d$ z a s]i\s objection to its use1 & ! specifications 7 drawn limit+ ! am\nt ( lime 9 ! s&4 ,?is exclud$ all ( ! local bank s&s4 ,! riv]-s&s :i* 7 us$ 7 ne>ly free f lime1 & 9 ! end ! s& z secur$ 0 probably n only free f lime1 b m satisfactory 9 o!r ways1 & also *eap] ?an ! bank-s& w\ld h be54 ,illu/ration3 ,,me*anical ,,composition ,,( ,,filt] ,,s& ,,& ,,gravels4 7,,arr[s ,,%[ ,,requirem5t ,,( ,,specification7 ,diamet]s 9 ,millimet]s ,,fig4 #h4 ,! specifications ( ! filt]-s& require t 8,! filt]-s& %all be clean riv]-1 bea*-1 or bank-s&1 ) ei!r %>p or r\nd$ gra9s4 ,x %all be entirely free f clay1 du/1 or organic impurities1 & %all1 if necess>y1 be wa%$ to remove su* mat]ials f x4 ,! gra9s %all1 all ( !m1 be ( h>d mat]ial :i* w n dis9tegrate1 & %all be ( ! foll[+ diamet]s3 ,n m ?an #a p] c5t1 by weight1 less ?an #j4ac mm41 nor m ?an #aj p] c5t less ?an #j4bg mm42 at lea/ #aj p] c5t1 by weight1 %all be less ?an #j4cf mm41 & at lea/ #gj p] c5t1 by weight1 %all be less ?an #a mm41 & no p>ticles %all be m ?an #e mm4 9 diamet]4 ,! diamet]s ( ! s&-gra9s w be comput$ z ! diamet]s ( sph]es ( equal volume4 ,! s& %all n conta9 m ?an #b p] c5t1 by weight1 ( lime & magnesia tak5 toge!r & calculat$ z c>bonates40 ,illu/ration3 ,,plac+ ,,! ,,concrete ,,vault+4 ,illu/ration3 ,,g5]al ,,view ,,( ,,vault+1 ,,"u ,,con/ruction4 ,to face page #cjb4 ,illu/ration3 ,,fig4 #i4 ,! s& 0 obta9$ f ! riv] at v>i\s places by dr$g+4 ,x 0 fir/ tak5 up by dipp]-dr$ges1 & br\ght 9 sc[s to a po9t 9 ! back *annel a little nor? ( ! filt]-plant4 ,x 0 !re dump$ 9 a specially prep>$ place 9 ! bottom ( ! riv]1 f :i* x 0 lift$ by a hydraulic dr$ge & pump$ ?r\gh a #ae-;in* pipe an av]age di/ance ( #ebe feet to po9ts select$1 & v>i$ f "t to "t1 on ! flats nor? ( ! filt]s4 ,! wat] conta9+ ! s& 0 !n put ?r\gh scre5s hav+ me%es :i* exclud$ all /ones #e mm4 9 diamet] & ov]1 & 0 !n tak5 into bas9s :]e ! s& 0 deposit$ & aft]w>d c>t$ to ! filt]s4 ,two ejector s&-wa%+ ma*9es1 %[n 9 ,fig4 #i1 are provid$ at conv5i5t places betwe5 ! filt]s4 ,9 !m ! dirty s& is mix$ ) wat]1 & is ?r[n up by an ejector1 aft] :i* x runs ?r\gh a *ute into a receptacle1 f :i* x is aga9 lift$ by ano!r ejector4 ,x passes 9 all ?r\gh five ejectors1 "p ( ! dirty wat] be+ wa/$ ea* "t4 ,! s& is f9ally collect$ f ! la/ ejector1 :]e x is all[$ to deposit f ! wat]4 ,wat] is admitt$ to ea* filt] ?r\gh a #bj-;in* pipe f a pipe sy/em connect+ ) ! s$im5tation-bas94 ,j inside ( ! filt]-wall is plac$ a /&>d gate1 & beyond t a balanc$ valve connect$ ) an adju/able float to %ut (f ! wat] :5 x rea*es ! desir$ height on ! filt]4 ,^! valves & floats 7 con/ruct$ f special designs1 & are simil> 9 pr9ciple to valves us$ = ! same purpose 9 ! ,b]l9 wat]-filt]s4 ,ea* filt] is provid$ ) an ov]fl[1 s arrang$ t x _c be clos$1 :i* prev5ts ! wat]-level f exce$+ a fix$ limit 9 case ! balanc$ valve fails to act4 ,an outlet is also provid$ ne> ! s&-run1 s t unfilt]$ wat] c be remov$ quickly f ! surface ( ! filt]1 %\ld x be necess>y1 to facilitate clean+4 ,! outlet ( ea* filt] is ?r\gh a #bj-;in* gate controll$ by a /&>d graduat$ to %[ ! exact di/ance ! gate is op54 ,! wat] rises 9 a *amb] & fl[s ?r\gh an orifice 9 a brass plate #d by #bd in*es1 ! c5tre ( :i* is #a foot bel[ ! level ( ! s&-l9e4 ,at ! nom9al rate ( filtration1 #c1jjj1jjj gallons p] acre daily1 #a foot ( head is requir$ to =ce ! wat] ?r\gh ! orifice4 ,) o!r rates ! head increases or decreases approximately z ! squ>e ( ! rate & =ms a measure ( x4 ,) wat] /&+ 9 ! l[] *amb]1 s t ! orifice is subm]g$1 x is assum$ t ! same rates w be obta9$ ) a giv5 diff]5ce 9 level betwe5 ! wat] on ! two sides ( ! orifice z f an equal head above ! c5tre ( ! orifice :5 dis*>g+ into air4 ,measurem5t ( ,efflu5t4--,9 ord] to %[ ! rate ( filtration two floats are connect$ ) ! wat] on ! two sides ( ! orifice4 ,^! floats are c\nt]balanc$2 "o c>ries a graduat$ scale1 & ! o!r a m>k] :i* moves 9 front ( ! scale & %[s ! rate ( filtration correspond+ to ! diff]5ce 9 level ( ! wat] on ! two sides4 ,:5 ! wat] 9 ! l[] *amb] falls bel[ ! c5tre ( ! orifice1 ! wat] 9 ! float-*amb] is nev]!less ma9ta9$ at ?is level4 ,?is is accompli%$ by mak+ ! l[] "p ( ! tube wat]-tight1 ) op5+s j at ! desir$ level1 s t :5 ! wat] falls bel[ ?is po9t 9 ! out] *amb] x does n fall 9 ! float-*amb]4 ,to prev5t ! loss ( wat] 9 ! float-*amb] by evaporation or f o!r causes1 a lead pipe is br\ght f ! o!r *amb] & supplies a driblet ( wat] to x con/antly2 ?is ov]fl[s ?r\gh ! op5+s1 & ma9ta9s ! wat]-level at precisely ! desir$ po9t4 ,! floats ?us indicate ! diff]5ce 9 wat]-level on ! two sides ( ! orifice :5ev] ! wat] 9 ! l[] *amb] is above ! c5tre ( ! orifice2 o!rwise !y indicate ! height ( wat] 9 ! upp] *amb] above ! c5tre ( ! orifice1 reg>dless ( ! wat]-level 9 ! l[] *amb]4 ,! scale is graduat$ to %[ ! rates ( filtration 9 millions ( gallons p] acre ( filt]+ area4 ,9 comput+ ?is scale ! area ( ! filt]s is tak5 z #j4g acre1 & ! coeffici5t ( dis*>ge z #j4fa4 ,at ! ord9>y rates ( filtration ! errors introduc$ by ! diff]5t conditions "u :i* ! orifice op]ates w r>ely am\nt to z mu* z #ajj1jjj gallons p] acre daily1 or "o ?irtie? ( ! ord9>y rate ( filtration4 ,usually !y are mu* less ?an ?is4 ,! app>atus ?us %[s directly1 & ) sub/antial accuracy1 ! rate ( filtration "u all conditions4 ,measurem5t ( ,loss ( ,head4--,two o!r floats ) simil> connections %[ ! diff]5ce 9 level betwe5 ! wat] /&+ on ! filt] & ! wat] 9 ! ma9 dra9-pipe back ( ! gate1 or1 9 o!r words1 ! frictional resi/ance ( ! filt]1 includ+ ! dra9s4 ,?is is commonly call$ ! loss ( head1 & increases f #j4b foot or less1 ) a p]fectly clean filt]1 to #d feet ) ! filt] ready = clean+4 ,:5 ! loss ( head exce$s #d feet ! rate ( filtration _c be ma9ta9$ at #c1jjj1jjj gallons p] acre daily ) ! outlet devices provid$1 &1 9 ord] to ma9ta9 ! rate1 ! filt] mu/ be clean$4 ,adju/m5t ( ,gauges4--,! adju/m5t ( ! gauges %[+ ! rate ( filtration & loss ( head is extremely simple4 ,:5 a filt] is put 9 s]vice ! gates f ! l[] *amb] to ! pure-wat] res]voir & to ! dra9 are clos$1 ! outlet ( ! filt] op5$1 & bo? *amb]s all[$ to fill to ! level ( ! wat] on ! filt]4 ,! l5g? ( ! wire c>ry+ ! gauge is !n adju/$ s t ! gauge w make ! desir$ run )\t hitt+ at ei!r end1 & !n ! m>k] is adju/$4 ,z bo? ! rate ( filtration & loss ( head are z]o "u ^! conditions1 x is only necess>y to set ! m>k]s to read z]o on ! gauges to adju/ !m4 ,! gates c !n be op5$ = regul> op]ation1 & ! read+s on ! gauges w be correct4 ,illu/ration3 ,,int]ior ,,( ,a ,,filt]3 ,,dra91 ,,gravel ,,& ,,s& ,,lay]s4 ,illu/ration3 ,,int]ior ,,( ,a ,,filt]1 ,,ready ,,= ,,use4 ,to face page #cjf4 ,x is necess>y to use wires :i* are light1 flexible1 & :i* w n /ret*4 ,at fir/ piano-wire1 ,no4 #bg ,b4 ,s4 gauge1 0 us$1 & 0 well adapt$ to ! purpose1 except t x ru/$ rapidly4 ,because ( ! ru/+ x 0 f\nd necess>y to sub/itute ano!r wire1 & cold-drawn copp] wire1 ,no4 #bd ,b4 ,s4 gauge1 0 us$ ) fair results4 ,/ret*+ is less s]i\s ?an x w\ld o!rwise be1 z ! correctness ( ! adju/m5t c be obs]v$ & correct$ readily e "t a filt] is out ( s]vice4 ,f ! l[] *amb]s 9 ! regulator-h\ses ! wat] fl[s ?r\gh gates to ! pipe sy/em lead+ to ! pure-wat] res]voir4 ,dra9-pipes are also provid$ :i* all[ ! wat] to be entirely drawn out ( ea* filt]1 %\ld t be necess>y = any reason1 & )\t int]f]+ ) ! o!r filt]s or ) ! pure-wat] res]voir4 ,! outlets ( ! filt]s are connect$ 9 pairs1 s t filt]$ wat] c be us$ = fill+ ! und]dra9s & s& ( ! filt]s f bel[ prior to />t+1 ?us avoid+ ! di/urbance :i* results f br++ dirty wat] ^u ! s& ( a filt] n fill$ ) wat]4 ,laboratory ,build+4--,! sci5tific control ( filt]s is reg>d$ z "o ( ! ess5tials to ! be/ results1 & to provide = ?is !re is a laboratory build+ at "o end ( ! c5tral c\rt betwe5 ! filt]s & close to ! s$im5tation-bas91 suppli$ ) ! necess>y equipm5t = full bact]ial exam9ations1 & also ) facilities = obs]v+ ! colors & turbidities ( raw & filt]$ wat]s1 & = mak+ su* *emical exam9ations z may be necess>y4 ,?is build+ also provides a com=table (fice1 d>k room1 & /orage room = tools1 etc41 us$ 9 ! "w4 ,pure-wat] ,res]voir4--,a small pure-wat] res]voir1 #id feet squ>e & hold+ ab\t #fjj1jjj gallons1 is provid$ at ! filt]-plant4 ,! con/ruction is simil> to t ( ! filt]s1 b ! %apes ( ! pi]s & vault+ 7 *ang$ slightly1 z !re 0 no necessity = ! l$ges ab\t ! bottoms ( ! pi]s & walls2 :ile provision is made = tak+ ! ra9-wat]1 fall+ ^u ! vault+ above1 to ! ne>e/ filt]s in/ead ( all[+ x to ent] ! res]voir4 ,! floor & ro( ( ! res]voir are at ! same levels z ^? ( ! filt]s4 ,,capacity ,,( ,,plant ,,& ,,means ,,( ,,regulation4 ,! v>i\s filt]s h effective filt]+ areas ( f #j4gjb to #j4gjd acre1 dep5d+ ^u slight diff]5ces 9 ! ?ickness ( ! walls 9 diff]5t places4 ,= ! purpose ( computation1 ! area ( ea* filt] is tak5 at #j4g acre4 ,! nom9al rate ( filtration is tak5 z #c1jjj1jjj gallons p] acre daily1 at :i* rate ea* filt] w yield #b1ajj1jjj gallons daily1 &1 ) "o filt] out ( use = ! purpose ( be+ clean$1 sev5 filt]s normally 9 use w yield #ad1gjj1jjj gallons4 ,! entrances & outlets are all made ( suffici5t size1 s t rates #ej p] c5t great] ?an ! =ego+ are possible4 ,! capacities ( ! intake1 pump+-/ation1 & pip+ are su* z to supply any quantity ( wat] :i* ! filt]s c take1 up to an extreme maximum ( #be1jjj1jjj gallons 9 #bd h\rs4 ,! pure-wat] conduit f ! filt]s to ,quack5bu% ,/reet is nom9ally rat$ at #be1jjj1jjj gallons p] #bd h\rs1 aft] x has become old & some:at tub]culat$4 ,9 its pres5t excell5t condition x w c>ry a l>g] quantity1 ,at ! pump+-/ation at ,quack5bu% ,/reet !re are ?ree ,allis pumps1 ea* capable ( pump+ #e1jjj1jjj gallons p] #bd h\rs4 ,9 addition to ! above !re are ! old res]ve pumps ) a nom9al capacity ( #aj1jjj1jjj gallons p] #bd h\rs1 :i* c be us$ if necess>y1 b :i* require s mu* coal t !y are seldom us$4 ,= practical purposes ! #ae1jjj1jjj gallons repres5ts ! pump+ capacity ( ?is /ation & also ! capacity ( ! filt]s1 b ! arrangem5ts are su* t 9 case ( em]g5cy ! supply c be increas$ to #bj1jjj1jjj or ev5 #be1jjj1jjj gallons = a %ort "t4 ,! wat] is pump$ ?r\gh ris+ ma9s to res]voirs hold+ #cg1jjj1jjj gallons1 n includ+ ! ,tivoli l[-s]vice res]voir1 :i* is usually suppli$ f gravity s\rces4 ,! res]voir capacity is su* t ! pump+ c be susp5d$ at ,quack5bu% ,/reet = consid]able p]iods if necess>y1 & 9 practice x has be5 susp5d$ at c]ta9 times1 especially on ,sundays4 ,! am\nt ( wat] requir$ is also some:at irregul>4 ,! dra9age areas supply+ ! gravity res]voirs are mu* l>g]1 relatively1 ?an ! res]voirs1 & at flood p]iods ! volume ( ! gravity supply is mu* great] ?an t :i* c be drawn 9 dry wea!r4 ,?us x happ5s t1 at c]ta9 seasons ( ! ye>1 ! am\nt ( wat] to be pump$ is b a fraction ( ! nom9al capacity ( ! pumps1 & at ^! times x is possible to %ut ! pumps d[n = great] l5g?s ( "t4 ,capacity ( ,pure-wat] ,res]voir4--,! /orage capacity provid$ betwe5 ! filt]s & ! ,quack5bu% ,/reet pumps is comp>atively small1 namely1 #fjj1jjj gallons1 or "o h\r's supply at ! full nom9al rate4 ,a l>g] bas91 hold+ z mu* z "o ?ird or "o half ( a day's supply1 w\ld be 9 _m respects desirable 9 ?is position1 b ! conditions 7 su* z to make x practically impossible4 ,! bottom ( ! res]voir c\ld n be put l[] )\t deep5+ & increas+ greatly ! exp5se ( ! conduit-l9e4 ,on ! o!r h&1 ! fl[-l9e ( ! res]voir c\ld n be rais$ )\t rais+ ! level ( ! filt]s1 :i* 0 h>dly possible ^u ! site select$4 ,! available dep? ( ! res]voir 0 ?us limit$ betwe5 v n>r[ b\nds1 & to secure a l>ge capacity w\ld h necessitat$ a v l>ge area1 & consequ5tly a great exp5se4 ,"u ^! circum/ances1 & especially 9 view ( ! abundant /orage capacity = filt]$ wat] 9 ! di/ribut+ res]voirs1 x 0 n deem$ necess>y to provide a l>ge /orage1 & only s mu* 0 provid$ z w\ld all[ ! pumps to be />t$ at ! conv5i5ce ( ! eng9e]1 & give a reasonable l5g? ( "t = ! filt]s to be br\ght into op]ation4 ,= ?is ! pure-wat] res]voir is ample1 b x is n en\gh to balance any cont9u$ fluctuations 9 ! rate ( pump+4 ,me?od ( ,regulat+ & ,*ang+ ! ,rate ( ,filtration4--,) all ! ,allis pumps runn+ at _! nom9al capacity1 ! quantity ( wat] requir$ w j ab\t equal ! nom9al capacity ( ! filt]s4 ,:5 only "o or two pumps are runn+1 ! rate ( filtration c be r$uc$4 ,) ! plant op]at+ up to its full capacity1 ! wat]-level 9 ! pure-wat] res]voir w be bel[ ! level ( ! /&>d orifices 9 ! filt] outlets4 ,:5 ! rate ( pump+ is r$uc$1 if no *ange is made 9 ! gates controll+ ! filt] outlets1 ! wat] w gradually rise 9 ! pure-wat] res]voir & 9 ! v>i\s regulator *amb]s1 & w subm]ge ! orifices & gradually r$uce ! head on ! filt]s1 & consequ5tly ! rates ( filtration1 until ^? rates equal ! quantity pump$4 ,9 case ! pump+ is /opp$ altoge!r1 ! filt]s w keep on deliv]+ at gradually r$uc$ rates until ! wat]-level 9 ! pure-wat] res]voir rea*es t ( ! wat] on ! filt]s4 ,:5 ! pumps are />t$ up1 aft] su* /oppage or r$uc$ rate ( pump+1 ! wat]-levels 9 ! pure-wat] res]voir & 9 ! gate-*amb]s w be l[]$ gradually1 & ! filt]s w />t to op]ate x fir/ ) extremely l[ rates1 :i* w increase gradually until ! wat] is depress$ bel[ ! orifices1 :5 !y w aga9 rea* ! rates at :i* !y 7 la/ set4 ,! regulators dur+ all ?is "t w %[ ! rate ( filtration on ea* filt]1 &1 if any inequalities occur :i* dem& correction1 ! gates on ! v>i\s outlets c be adju/$ accord+ly4 ,illu/ration3 ,,c5tral ,,c\rt1 ,,%[+ ,,s&-,,wa%]1 ,,dirty ,,s&1 ,,etc4 ,illu/ration3 ,,s$im5tation ,,bas91 ,,filt]s1 ,,etc4 ,to face page #caj4 ,! arrangem5t1 9 ?is respect1 comb9es "s ( ! features ( ! ,engli% & ,g]man plants4 ,9 ! ,engli% plants ! filt]s are usually connect$ directly ) ! cle>-wat] bas91 & t 9 turn ) ! pumps1 & ! spe$ ( filtration is requir$ to respond to ! spe$ ( ! pumps1 increas+ & decreas+ ) x1 be+ regulat$ at all times by ! height ( wat] 9 ! pure-wat] res]voir4 ,?is arrangem5t has be5 subject to sev]e criticism1 because ! rate ( filtration fluctuates ) ! consumption1 & especially because ! rates ( filtration obta9$ simultane\sly 9 diff]5t filt]s may be diff]5t4 ,!re 0 no way to det]m9e at :at rate any individual filt] 0 work+1 & !re 0 always a t5d5cy = a fre%ly scrap$ filt] to op]ate mu* m rapidly ?an ^? :i* _h n be5 scrap$ = "s "t4 ,?is l$ to ! proc$ure1 fir/ =mulat$ by ! ,commission ( ,g]man ,wat]-works ,eng9e]s 9 #ahid1 & provid$ = 9 mo/ ( ! ,g]man works built or remodell$ s9ce t "t1 ( provid+ pure-wat] /orage suffici5t 9 am\nt to make ! rate ( filtration entirely indep5d5t ( ! op]ation ( ! pumps4 ,ea* filt] 0 to be controll$ by itself1 be indep5d5t ( ! o!rs1 & deliv] its wat] into a pure-wat] res]voir l[] ?an itself1 s t x c\ld nev] be affect$ by back-wat]1 & s l>ge t !re w\ld nev] be a dem& = sudd5 *anges 9 ! rate ( filtration4 ,?is proc$ure has giv5 excell5t results 9 ! ,g]man works2 b x leads (t5times to exp5sive con/ruction4 ,x involves1 9 ! fir/ place1 a mu* great] loss ( head 9 pass+ ?r\gh ! works1 because ! pure-wat] res]voir mu/ be l[] ?an ! filt]s1 & ! co/ ( ! pure-wat] res]voir is increas$ greatly because ( its l>ge size4 ,! regulation ( ! filt]s is put ^u ! att5dants entirely1 or ^u automatic devices1 & regulation by :at is kn[n z 8respond+ to ! pumps0 is elim9at$4 ,m rec5tly1 ! ,g]man au?orities h %[n less disposition to insi/ rigidly ^u ! pr9ciples advanc$ 9 #ahid4 ,9 a compilation ( ! results ( sev]al ye>s' exp]i5ce ) ,g]man wat]-filt]s1 ,dr4 ,pannwiz#ff makes a /atem5t ( p>ticul> int]e/1 ( :i* a free translation is z foll[s3 8,mo/ ( ! ,g]man works h suffici5t pure-wat] res]voir capacity to balance ! normal fluctuations 9 consumption1 s t ! rate ( filtration is at lea/ indep5d5t ( ! h\rly fluctuations 9 consumption4 ,( especial importance is ! sup]ficial area ( ! pure-wat] res]voir4 ,if x is suffici5tly l>ge1 !re is no objection to all[+ ! wat]-level 9 x to rise to t ( ! wat] ^u ! filt]s4 ,) v l[ rates ( consumption dur+ ! night ! filt]s may "w sl[ly & ev5 /op1 )\t damage to ! s$im5t lay]s :5 ! /opp+ & />t+ take place sl[ly & regul>ly1 because ( ! ample res]voir area40 8,! v consid]able fluctuations f day to day1 especially ^? aris+ f unusual & un=ese5 occurr5ces1 are n provid$ = entirely by ev5 v l>ge & well-arrang$ res]voirs4 ,to provide = ^! )\t caus+ %ock1 ! rate ( filtration mu/ be *ang$ c>efully & gradually1 & ! fir/ ess5tial to success is a good regulation app>atus40 8,respond+ to ! pumps0 has a great deal to recomm5d x4 ,x all[s ! pure-wat] res]voir to be put at ! highe/ possible level1 x r$uces to a m9imum ! loss ( head 9 ! plant1 & yet provides automatically1 & )\t ! slighte/ tr\ble on ! "p ( ! att5dants1 = ! deliv]y ( ! requir$ quantity ( wat] by ! filt]s at all times4 ,if ! filt]s are connect$ directly to ! pumps !re is a t5d5cy = ! pulsations ( ! pumps to di/urb _! op]ation1 :i* is highly objectionable1 ev5 if ! pumps are f> remov$2 & ?is exi/s :]e filt]s are connect$ directly to ! pumps1 & a pure-wat] res]voir is atta*$ to !m indirectly4 ,by tak+ all ! wat] ?r\gh ! pure-wat] res]voir & hav+ no connection except ?r\gh x1 ?is condition is absolutely avoid$1 & ! pull on ! filt]s is at all times p]fectly /eady4 ,mu* has be5 said z to ! effect ( v>iation 9 ! rate ( filtration ^u ! effici5cy ( filt]s4 ,exp]im5ts h be5 made at ,lawr5ce & else:]e :i* h %[n t1 z long z ! maximum rate does n exce$ a prop] "o1 & "u reasonable regulations1 & ) ! filt] 9 all respects 9 good ord]1 no m>k$ decrease 9 effici5cy results f mod]ate fluctuations 9 rate4 ,!re is probably a great] decrease 9 effici5cy by /opp+ ! filt] altoge!r1 especially if x is done sudd5ly1 ?an by simply r$uc+ ! rate4 ,! =m] sometimes results 9 loos5+ air-bubbles 9 ! s&1 :i* rise to ! surface & cause di/urbances1 b ?is is n (t5 caus$ by simple *ange 9 rate4 ,on ! :ole1 !re is little evid5ce to %[ t1 )9 reasonable limits1 fluctuations 9 rate are objectionable1 or %\ld be exclud$ entirely1 especially 9 su* cases z at ,albany1 :]e arrangem5ts to prev5t !m w\ld h result$ 9 v greatly increas$ fir/ co/4 ,! inf]ior results sometimes obta9$ ) ! sy/em ( 8respond+ to ! pumps0 z x exi/$ 9 e>li] works1 & /ill exi/s 9 _m important places1 und\bt$ly arises f ! fact t !re is no means ( kn[+ & controll+ ! simultane\s rate ( filtration 9 diff]5t filt]s1 & t "o filt] may be filt]+ two or ?ree times z fa/ z ano!r1 ) no?+ to indicate x4 ,?is cont+5cy is fully provid$ = 9 ! ,albany plant4 ,! orifices are ( su* size t ev5 ) a filt] j scrap$ & put 9 s]vice1 ) ! m9imum loss ( head1 ) ! outlet-gate wide op51 & ) ! wat]-level 9 ! pure-wat] res]voir cle> d[n--t is1 ) ! mo/ unfavorable conditions :i* c\ld possibly exi/--! rate ( filtration _c exce$ #e1jjj1jjj or #f1jjj1jjj gallons p] acre daily1 or d\ble ! nom9al rate4 ,?is rate1 :ile mu* too high = a filt] :i* has j be5 clean$1 is n ne>ly z high z 0 possible1 & 9 fact actually occurr$ 9 ! old ,/ralau filt]s at ,b]l91 & 9 _m ,engli% works2 &1 fur!r1 su* a condition c\ld only occur ?r\gh ! gross neglig5ce ( ! att5dants1 because ! rate ( filtration is indicat$ cle>ly at all times by ! gauges4 ,^! regulat+-devices h be5 specially design$ to %[ ! rate ) unmi/akable cle>ness1 s t no att5dant1 h[ev] /upid1 c make an error by an incorrect computation f ! gauge heights4 ,x is believ$ t ! advantage ( cle>ness by ?is proc$ure is mu* m important ?an any increas$ accuracy :i* might be secur$ by ref9em5ts 9 ! me?od ( computation1 :i* %\ld take into acc\nt v>iations 9 ! value ( ! coeffici5t ( dis*>ge1 b :i* w\ld r5d] direct read+s impossible4 ,9 design+ ! ,albany plant ! object has be5 to comb9e ! be/ features ( ,g]man regulation ) ! economical & conv5i5t features ( ! old] ,engli% sy/em1 & filt]s are all[$ to respond to ! pumps )9 c]ta9 limits1 :ile gu>d+ aga9/ ! dang]s ord9>ily incid5t !reto4 ,,results ,,( ,,op]ation4 ,! filt]s 7 design$ to remove f ! wat] ! bact]ia :i* cause disease4 ,!y h already rea*$ a bact]ial effici5cy ( ov] #ii p] c5t1 & x is expect$ t _! use w result 9 a great r$uction 9 ! dea?-rate f wat]-borne diseases 9 ! city4 ,!y also remove a "p ( ! color & all ( ! susp5d$ matt]s & turbidity1 s t ! wat] is satisfactory 9 its physical prop]ties4 ,! filt]s h rea*$ ) p]fect ease _! rat$ capacity1 & on sev]al occasions h be5 op]at$ to deliv] "o ?ird m ?an ?is am\nt2 t is to say1 at a rate ( #d1jjj1jjj gallons p] acre1 daily4 ,,co/ ,,( ,,con/ruction4 ,! approximate co/ ( ! filtration-plant complete 0 z foll[s3 ,l& #h1bij ,pump+-/ation & intake #di1gde ,filt]s & s$im5tation-bas91 ) pip+ #cbc1ifj ,pure-wat] conduit & connection ) ,quack5bu% ,/reet pump+-/ation #hf1fch ,eng9e]+ & m9or exp5ses #bh1jjj ---------------- ,total #dif1fcc ,! filt]s1 s$im5tation-bas91 & pure-wat] res]voir are connect$ 9 su* a way z to make an exact sep>ation ( _! co/s impossible2 b1 approximately1 ! s$im5tation-bas9 co/ #fj1jjj1 ! pure-wat] res]voir #i1jjj1 & ! filt]s #bee1jjj4 ,! s$im5tation-bas9 ?us co/ #d1ajj p] million gallons capacity2 & ! filt]s complete co/ #de1fjj p] acre ( net filt]+ area1 includ+ all pip+1 (fice & laboratory build+1 b exclusive ( l& & eng9e]+4 ,,ackn[l$gm5t4 ,! g5]al plan & location ( ! plant 7 fir/ conceiv$ by ! ,sup]9t5d5t ( ,wat]-works1 ,george ,i4 ,bailey1 ,m4 ,am4 ,soc4 ,c4 ,e41 & ! successful execution is l>gely due to 8 ef=ts4 ,! memb]s ( ! ,wat] ,bo>d1 & especially ! ,con/ruction ,committee1 h foll[$ ! "w 9 detail closely & p]sonally1 & _! int]e/ & support h be5 ess5tial factors 9 ! results accompli%$4 ,9 ! designs & specifications = ! pure-wat] conduit ! au?or is greatly indebt$ to ,emil ,kui*l+1 ,m4 ,am4 ,soc4 ,c4 ,e41 & also = mo/ valuable sugge/ions relative to ! p]=mance ( ?is "p ( ! "w4 ,to ,william ,:eel]1 ,m4 ,am4 ,soc4 ,c4 ,e41 ( ,bo/on1 ! au?or is indebt$ = advice ^u ! vault+ & cross-sections ( ! walls1 & ^! matt]s 7 submitt$ to him be=e ! plans 7 put 9 f9al %ape4 ,all ! ar*itectural designs h be5 suppli$ by ,mr4 ,a4 ,w4 ,full]1 ( ,albany4 ,w4 ,b4 ,full]1 ,m4 ,am4 ,soc4 ,c4 ,e41 z ,resid5t ,eng9e]1 has be5 9 direct *>ge ( ! "w1 & its success is l>gely due to 8 int]e/ 9 x & ! close att5tion :i* he & ! assi/ant eng9e]s h giv5 x4 ,,footnotes3 #a ,! ,am]ican gallon is #bca cubic in*es or #j4hccc ( ! imp]ial gallon4 ,9 ?is "w ,am]ican gallons are always us$1 & ,engli% quantities are /at$ 9 ,am]ican1 n imp]ial1 gallons4 #b ,filtration ( ,riv] ,wat]s4 ,van ,no/r& ,co41 #ahfi4 #c ,annual ,report ( ,alb]t ,f4 ,noyes1 ,city ,eng9e] = #ahia4 #d ,rept4 ,mass4 ,/ate ,bo>d ( ,heal?1 #ahib1 p4 #eda4 ,see ,app5dix ,,iii4 #e ,! me?od ( calculat+ ! size is giv5 9 ,app5dix ,,iii4 #f ,a full table ( frictions ) v>i\s velocities & gravels 0 giv5 9 ! ,rept4 ( ,mass4 ,/ate ,bo>d ( ,heal?1 #ahib1 p4 #eee4 #g ,frhl+1 ,h&bu* d] ,+5ieurwiss5s*aft51 ,,ii4 ,b&1 ,,vi4 ,kapitel4 #h ,! ,am]ican gallon is us$ ?r\gh\t ?is book2 ! ,engli% gallon is "o fif? l>g]4 #i ,piefke1 ,zeits*rift fr ,hygi5e1 #ahid1 p4 #agg4 #aj ,zeits*rift fr ,hygi5e1 #ahia1 page #ch4 #aa ,j\rnal fr ,gas- u4 ,wass]v]sorgung1 #ahia1 #bjh & #bbh4 #ab ,j\rnal fr ,gas- u4 ,wass]v]sorgung1 #ahic1 #afa4 #ac ,samuelson's translation ( ,kirkwood's 8,filtration ( ,riv]-wat]s20 ,l9dley1 ,die ,nutzb>ma*ung des ,flusswass]s1 ,j\rnal fr ,gas- u4 ,wass]v]sorgung1 #ahij1 #eja2 ,kais]li*5 ,gesundheitsamt1 ,grundstze fr die ,re9igung von ,ob]fl*5wass] dur* ,s&filtration2 ,j\rnal fr ,gas- u4 ,wass]v]sorgung1 #ahid1 ,app5dix ,i4 #ad ,l9dley1 ,j\rnal fr ,gas- u4 ,wass]v]sorgung1 #ahij1 #eja2 ,grahn1 ,j\rnal fr ,gas- u4 ,wass]v]sorgung1 #ahij1 #eaa2 ,halb]tsma1 ,j\rnal fr ,gas- u4 ,wass]v]sorgung1 #ahib1 #fhf2 ,piefke1 ,zeits*rift fr ,hygi5e1 #ahid1 #aea2 & o!rs4 #ae ,app5dix ,i4 #af ,! ,wat] ,supply ( ,t[ns4 ,london1 #ahid4 #ag ,a special species ( bact]ia artificially add$ to secure m precise in=mation 9 reg>d to ! passage ( g]ms ?r\gh ! filt]4 #ah ,zeits*rift fr ,hygi5e1 #ahid1 p4 #agc4 #ai ,report ,mass4 ,/ate ,bo>d ( ,heal? = #ahia1 p4 #dch2 #ahib1 page #dji4 #bj ,app5dix ,,iv4 #ba ,piefke1 ,zeits*rift fr ,hygi5e1 #ahid1 p1 #agg4 #bb ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahhg1 p4 #eie4 #bc ,zeits*rift fr ,hygi5e1 #ahid1 p4 #agb4 #bd ,app5dix ,,iv4 #be ,app5dix ,i4 #bf ,glas]'s ,annal51 #ahhf1 p4 #dh2 ,zeit4 f4 ,hygi5e1 #ahhi1 p4 #abh4 #bg ,vi]teljahress*rift fr ff5tli*e ,gesundheitspflege1 #ahia1 p4 #ei4 #bh ,j\rnal fr ,gas- und ,wass]v]sorgung1 #ahia1 #ajh4 #bi ,zeits*rift fr ,hygi5e1 #ahid1 #ahb4 #cj ,i am in=m$ t sev]al o!r filt]s ^u ! same pr9ciple h be5 m rec5tly built4 #ca ,report on ,wat] ,purification at ,c9c9nati1 page #cgh4 #cb ,translation 9 ,g]man 9 ,d+l]'s ,polyte*nical ,j\rnal1 #ahcb1 #chf4 #cc ,wat] ,purification at ,l\isville1 page #cgh4 #cd ,special ,report ,mass4 ,/ate ,bo>d ( ,heal? #ahij1 ,purification ( ,sewage & ,wat]1 page #gdg4 #ce ,wat] ,purification at ,c9c9nati1 p4 #dhe4 #cf ,j\r4 ( ! ,new ,engl& ,wat] ,works ,assoc41 ,vol4 ,,viii1 page #ahc4 #cg ,report ( ! ,pittsburg ,filtration ,commission1 #ahii1 page #ee4 #ch ,rhode ,isl& ,/ate ,bo>d ( ,heal? ,report = #ahid4 #ci ,report ( ! ,rhode ,isl& ,/ate ,bo>d ( ,heal? = #ahid4 #dj ,report on ! ,inve/igations into ! ,purification ( ! ,ohio ,riv] ,wat] at ,l\isville1 ,k5tucky4 ,d4 ,van ,no/r& ,co41 #ahih4 #da ,ohio ,/ate ,bo>d ( ,heal? ,report1 #ahig1 page #aed4 #db ,report ( ! ,pittsburg ,filtration ,commission1 ,city ,docum5t1 #ahii4 #dc ,full]1 ,wat] ,purification at ,l\isville1 page #dbe4 #dd ,w>r51 ,feb4 #i2 ,june #a2 ,july #f4 ,jewell1 ,july #a2 ,feb4 #i1 #af1 #ag4 #de 8,removal ( ,iron f ,gr\nd ,wat]s10 ,j\rnal ( ! ,new ,engl& ,wat] ,works ,association1 ,vol4 xi1 #ahig1 page #bgg4 #df ,j\rnal ( ! ,new ,engl& ,wat] ,works ,association1 ,vol4 ii1 page #bid4 ,description ( plant by ,supt4 ,lewis ,m4 ,bancr(t4 #dg ,?is numb] 0 ! result ( num]\s c\nts made f fces f p]sons suff]+ ) typhoid fev] 9 ! ,lawr5ce ,city ,hospital 9 #ahia & #ahib4 ,mr4 ,g4 ,w4 ,full] aft]w>d made at ! ,lawr5ce ,exp]im5t ,/ation "s fur!r inve/igation ( fces f heal?y p 9 :i* ! numb]s 7 consid]ably l[]1 usually less ?an #bjj1jjj1jjj1 p] gram & sometimes z l[ z #aj1jjj1jjj p] gram4 #dh ,^! exp]im5ts1 s f> z !y h come to ! notice ( ! au?or1 h be5 made ) wat] /]iliz$ by heat+1 usually 9 small tubes /opp]$ ) cotton-wool or o!r organic matt]4 ,9 ?is case ! wat]1 no matt] h[ c>efully purifi$ 9 ! fir/ place1 becomes an infusion ( organic matt]s capable ( support+ bact]ial gr[?s1 & n at all to be comp>$ to natural wat]s4 ,9 exp]im5ts (t5 repeat$ "u my direction1 c>efully di/ill$ wat] 9 bottles1 mo/ scrupul\sly clean1 ) glass /opp]s1 & protect$ f du/1 b n /]iliz$1 has uni=mly refus$ to support bact]ial gr[?s ev5 :5 cauti\sly se$$ at ! />t1 & ! same is usually true ( pure natural wat]s4 ,"s fur!r exp]im5ts %[$ h>dly any bact]ial gr[? ev5 ( ! mo/ h>dy wat] bact]ia 9 a solution #a "p ( peptone 9 #a1jjj1jjj1jjj p>ts ( di/ill$ wat]1 & solutions t5 times z /rong only gave mod]ate gr[?s4 #di ,! ,wat]-supply ( ,*icago3 ,its ,s\rce & ,sanit>y ,aspects4 ,by ,ar?ur ,r4 ,reynolds1 ,m4,d41 ,commission] ( ,heal? ( ,*icago1 & ,all5 ,haz54 ,am]ican ,public ,heal? ,association1 #ahic4 ,page #adf4 #ej ,j\rnal fr ,gas- u4 ,wass]v]sorgung1 #ahic1 #fid4 #ea ,j\rnal fr ,gas- u4 ,wass]v]sorgung1 #ahid1 #ahe4 #eb ,! me?od ( mak+ ?is det]m9ation 0 giv5 9 ! ,am]ican ,*emical ,j\rnal1 vol4 #ab1 p4 #dbg4 #ec ,"s ( ! companies secure "s gr\nd wat] :i* !y mix ) ! filt]$ wat]1 & ?is is includ$ 9 ! quantities = ! sep>ate companies1 b is exclud$ f ! totals = all ! companies by ye>s4 #ed ,exclusive ( gravity supplies4 #ee ,n 9 use4 #ef ,"u con/ruction4 #eg ,n 9 use4 #eh ,"u con/ruction4 #ei ,n 9 use4 #fj ,"u con/ruction4 #fa ,n 9 use4 #fb ,"u con/ruction4 #fc ,9 ! ,c5tralblatt fr ,bakt]iologie1 #ahie1 page #hha1 ,re9s* discusses at l5g? ! cause ( ! inf]ior results at ,altona 9 w9t]1 & has app>5tly discov]$ a new factor 9 produc+ !m4 ,ow+ to defective con/ruction ( ! outlets = ! s$im5tation-bas9s !y h fail$ to act prop]ly 9 pres5ce ( excessive quantities ( ice1 & ! s$im5t f ! bas9s has be5 dis*>g$ 9 l>ge quantity ^u ! filt]s1 & a small fraction ( ! _m millions ( bact]ia 9 x h pass$ ?r\gh ! filt]s4 ,he has exp]im5t$ ) ?is s$im5t appli$ to small filt]s1 & has become conv9c$ t to secure good "w "u all conditions a mu* deep] lay] ( s& ?an t g5]ally consid]$ necess>y mu/ be us$1 & 8 "w emphasizes ! importance ( ! action ( ! s& 9 di/9ction f ! action ( ! s$im5t lay]1 :i* has (t5 be5 ?\ght to be ! sole1 or at lea/ ! pr9cipal1 requirem5t ( good filtration4 #fd ,li*t- u4 ,wass]w]ke1 ,zri*1 #ahib1 page #cb4 #fe ,descriptions ( "s ( ! lead+ ,european gr\nd-wat] supplies 7 giv5 by ! au?or 9 ! ,j\r4 ,asso4 ,eng4 ,soc41 ,feb4 #ahie1 p4 #aac4 #ff 8,arbeit5 aus dem ,kais]li*5 ,gesundheitsamte10 vol4 xiv4 p4 #bfj4 ,,index4 ,albany1 ,n4 ,y41 filt]s at1 #bed1 #bhh4 ,alkal9ity1 #aee4 ,altona1 d\ble filtration at1 #aih4 filt]s at1 #bfe4 ,alum1 use (1 9 filtration1 #ib1 #add4 ,am]ican cities1 wat]-supplies (1 & typhoid fev] 91 #baa4 ,am/]dam1 filt]s at1 #bgb4 iron removal at1 #aib4 ,&]son process1 #adg4 ,antw]p1 filt]s at1 #bgb4 ,asbe/os z filt]+ mat]ial1 #aha4 ,asbury ,p>k1 iron removal at1 #aib4 ,a%l&1 ,wis41 filt]s at1 #beb4 ,area ( filt]s to be provid$1 #dg4 ,bact]ia1 app>5t & actual removal (1 by filt]s1 #hg4 f und]dra9s1 #hg4 9 ,elbe at ,altona1 #bbh4 9 fces1 #bae4 9 wat]1 #hd4 numb] to be all[$ 9 filt]$ wat]1 #bbb4 ( *ol]a 9 riv] wat]1 #bca4 ( typhoid fev]1 life (1 9 wat]1 #baf4 ( special k9ds to te/ effici5cy ( filtration1 #hf4 to be det]m9$ daily1 #bbb4 ,bact]ial exam9ation ( wat]1 #ic4 ,b]l91 regulation ( dep? ( wat]1 #ei4 *ol]a infantum f wat]1 #bbi4 friction 9 und]dra9s1 #dd4 regulation ( rate1 #ec1 #ee4 wat] works1 #bfa4 ,b]wyn1 ,p5n41 filt]s at1 #bec4 ,bo/on1 protection ( purity ( wat]-supply1 #aaj4 exp]im5tal filt]s at1 #gc4 ,brem51 d\ble filtration at1 #aih4 ,breslau1 filt]s at1 #bgd4 ,brussels1 gr\nd-wat]1 supply (1 #bgf4 ,budape/1 filt]s at1 #bgd4 ,burton1 regulation ( rate at ,tokyo1 ,japan1 #eh4 ,c>p5t]1 ,pr(4 ,l4 ,g41 #bd4 ,*emnitz1 int]mitt5t filtration at1 #ajg4 ,*icago1 r$uc$ dea?-rate ) new intake1 #bag4 ,*ol]a infantum f impure wat]1 #bbf4 ,*ol]a1 9 ,hamburg f wat]1 #bcj4 caus$ by wat]1 #bad4 ,cl>ification1 def9ition (1 #aac4 ,cl>k1 ,h4 ,w41 #bd1 #aij4 ,cl>k's process = s(t5+ wat]1 #ib1 #ade4 ,clay p>ticles1 size (1 #abc4 ,clean+ filt]s1 #fh4 ,coagulant1 absorption (1 by susp5d$ matt]s1 #aed4 successive applications (1 #aed4 ,coagulants us$ 9 practice1 #aej4 ,coagulation ( wat]s1 #add4 ,cologne1 wat]-supply (1 f wells1 #bgf4 ,color1 #aac4 am\nt ( coagulant requir$ to remove1 #aec4 am\nt (1 9 v>i\s wat]s1 #aae4 measurem5t (1 #aad4 ,color1 removal (1 #aag4 ,cont9u\s filt]s1 #e4 filtration1 nature (1 #hc1 #ib4 ,co/ ( filt]s & filtration1 #d1 #dh1 #ajb1 #bjj1 #cad4 ,cov]$ filt]s1 effici5cy (1 #ag4 ,cov]s = filt]s1 #ab1 #ae4 at ,albany1 #bie4 9 ! ,unit$ ,/ates1 #ag4 omitt$ at ,lawr5ce1 #aja4 ,cr5o?rix1 #aje1 #ahf4 ,di>rha f impure wat]1 #bbf4 ,dibd51 ,w4 ,j41 #abi4 ,disease f wat]1 #baj4 ,d\ble filtration at ,s*i$am1 #bgc4 ,dra9age areas ( a numb] ( riv]s1 #acc4 ,dresd51 wat]-supply (1 f filt]-gall]y1 #bgf4 ,dr[n1 ,dr4 ,?omas ,m41 #aej1 #aia4 ,effective size ( s&1 #ba1 #bch4 ,european s&s1 #be4 ,effici5cy ( filtration1 #hc1 #hh1 #ia4 effect ( rate ^u1 #ej4 effect ( size ( s&-gra9 ^u1 #cj4 effect ( ?ickness ( s& lay] ^u1 #cd4 at ,lawr5ce1 #ajf4 ,european filt]s1 #ia1 #bfj4 ,efflu5ts1 wa/+ aft] scrap+1 #gd4 ,fces1 numb] ( bact]ia 91 #bae4 ,f> ,rockaway1 ,l4 ,i41 filt]s at1 #aic1 #bec4 ,fill+ s& ) wat] f bel[1 #fh1 #cjg4 ,filt] b$s1 bottoms (1 mu/ be wat]-tight1 #ab4 cov]s =1 #ab4 =m (1 #aa4 size (1 #aj4 ,filt]s1 aggregate capacity (1 #bed4 dep?s ( wat]s on1 #de4 li/ ( cities us+1 #bdd4 res]ve area requir$1 #dg4 fir/ con/ruct$ at ,london1 #hc4 = h\sehold use1 #ahc4 g5]al arrangem5t (1 #f4 ,filt]s1 /ati/ics (1 at v>i\s cities1 #bda4 ,filtration1 co/ (1 #bjj4 degree ( purification requir$1 #e4 g5]al nature (1 #ib4 ,fis*] tile sy/em1 #aha4 ,fitz,gerald1 ,desmond1 #gc1 #aaa1 #aif4 ,flood fl[s n tak5 = supply1 #aj4 ,frnkel & ,piefke1 exp]im5ts on removal ( disease g]ms1 #hf4 ,frank=t on ,ma91 wat] supply (1 f spr+s1 #bgf4 ,frankl&1 ,dr4 ,p]cy1 #hd4 ,friction ( filt]$ wat] 9 pipes1 #bfd4 wat] 9 gravel1 #cg4 wat] 9 s&1 #bb4 wat] 9 und]dra9s1 #dj4 ,fro/1 effect (1 ^u filt]s1 #ab1 #bbi1 #bff4 ,frhl+1 on ! heat+ ( wat] by sun%9e1 #af4 und]dra9+ at ,knigsb]g1 #ci4 ,full]1 ,g4 ,w41 #aah1 #abc1 #aca1 #aci1 #adj1 #ade1 #aeb1 #aed1 #afa1 #afe4 ,g]man ,imp]ial ,bo>d ( ,heal?1 #cd1 #ea1 #ed1 #ge1 #ie4 regulations 9 reg>d to filtration1 #bba4 ,gill1 app>atus = regulation1 #ee4 ,glasg[1 wat]-supply (1 f ,lo* ,katr9e1 #bge4 ,gravel at ,albany1 #bii4 lay]s1 #ce4 friction ( wat] 91 #cg4 scre5+ (1 = filt]s1 #cg4 ,gr& ,=ks1 ,n4 ,d41 filt]s at1 #beb4 ,gr\nd-wat] supplies1 #c4 ! use (1 9 ,europe1 #bgf4 ,halb]tsma1 ,h4 ,p4 ,n41 #ed1 #ei4 ,hamburg1 app>atus = regulat+ dep? ( wat]1 #ei4 heal? (1 #bbf1 #bga4 regulation ( rate ( filtration1 #ef4 und]dra9s ( filt]s at1 #db4 wat]-supply (1 #bfi4 ,hamilton1 ,n4 ,y41 filt]s at1 #bec4 ,h>dness1 removal (1 #ib1 #ade4 ,h>risburg1 ,p5n41 filt]s at1 #bec4 ,h]many1 ,*>les1 #afa4 ,high rates ( filtration )\t coagulant1 #ahb4 ,h\sehold filt]s1 #ahc4 ,hudson1 ,n4 ,y41 filt]s at1 #bea4 ,ice on filt]s1 #ac4 ,inlet regulators1 #ei4 ,imp\nd+ res]voirs1 #b4 ,int]mitt5t filtration1 #ig4 application (1 #aaa1 #aig4 at ,*emnitz1 #ajg4 at ,lawr5ce1 #ajj4 ( ,pegan ,brook1 #aaj4 ,iron1 comp\nds (1 z coagulants1 #adf4 9 gr\nd-wat]s1 #ahf4 9 gr\nd-wat] at ,lawr5ce1 #aje4 metallic1 ! ,&]son process1 #adg4 pres5t z f]r\s sulphate1 #aia4 removal plants 9 op]ation1 #aib4 ,iron wat]s1 treatm5t (1 #ahi4 ,jewel filt]1 #aea1 #afa1 #afb1 #agb1 #agc4 ,kirkwood1 ,james ,p41 #h1 #cf1 #dg1 #ea1 #ee1 #fa1 #fc1 #fg4 ,kmmel1 #ej1 #ea1 #hf4 ,lamb]tsville1 ,n4 ,j41 filt]s at1 #beb4 ,lawr5ce ,city filt]1 description (1 #ajj4 ,lawr5ce ,exp]im5t ,/ation1 #ig4 air 9 wat] filt]$ 9 w9t] at1 #df4 dep? ( s& remov$ at1 #gj4 dep? ( wat] on filt]s1 #df4 effect ( loss ( head ^u effici5cy1 #fa4 effect ( size ( s&-gra9 ^u effici5cy1 #cb4 effect ( size ( s&-gra9 ^u frequ5cy ( scrap+1 #cb4 effici5cy ( filt]s at v>i\s rates1 #ej4 effici5cy ( filtration at1 #hf1 #hi4 exp]im5ts ) cont9u\s filtration1 #aaj4 filt]s ( f9e s&1 #ca4 filt]s ( v>i\s s&-gra9 sizes1 #cb4 gravel = filt]s at1 #ci4 gr[? ( bact]ia 9 /]iliz$ s& at1 #he4 int]mitt5t filtration inve/igat$1 #ig4 ,lawr5ce ,exp]im5t ,/ation1 me?od ( s& analysis at1 #bj4 quantities ( wat] filt]$ at v>i\s losses ( head1 #ff4 wa/+ efflu5ts n necess>y1 #ge4 ,lawr5ce1 typhoid fev] at1 #ajb4 ,leipzig1 wat]-supply (1 f wells1 #bgf4 ,lime 9 s&1 #bi4 /]iliz+ effect (1 #adf4 z a coagulant1 #ade4 application (1 to wat]1 #aeg4 ,l9dley1 #dc1 #ea1 #ed1 #eg1 #ha4 ,lit]ature on filtration1 #bgg1 #bhe4 ,little ,falls1 ,n4 ,y41 filt]s at1 #bec4 ,loam 9 filt]s1 #ce4 ,london1 co/ ( op]at+ filt]s at1 #bjb4 wat]-supply (1 #bee4 ,long1 ,pr(41 #aca4 ,lora91 te/s ( me*anical filt]s1 #afa4 ,loss ( head1 #eb4 limit to1 #fj1 #fg4 reasons = all[+ high1 #fe4 ,l\isville1 me*anical filt]s at1 #afa4 ,magdeburg1 filt]s at1 #bgc4 ,maign5 sy/em1 #aha4 ,man*e/]1 wat]-supply (1 #bge4 ,manganese1 comp\nds (1 z coagulants1 #adh4 9 gr\nd-wat]s1 #ahh4 ,massa*usetts ,/ate ,bo>d ( ,heal?1 see ,lawr5ce ,exp]im5t ,/ation4 ,me*anical filt]s1 #aei4 application (1 #aii4 effici5cy (1 #agi4 li/ (1 #bdg4 pressure filt]s1 #ahj4 rates ( filtration us$1 #age4 types (1 #agb4 wa/+ efflu5t aft] wa%+1 #afc4 ,mill=d1 ,mass41 filt]s at1 #beb4 ,mills1 ,h4 ,f41 #ig1 #ii1 #ajb4 ,m\nt ,v]non1 ,n4 ,y41 filt]s at1 #beb4 ,mud1 see turbidity4 ,muddy wat]s1 #aac4 ,muni*1 wat]-supply (1 f spr+s1 #bge4 ,ni*ols1 ,pr(41 susp5d$ matt]s 9 ,european /reams1 #aca4 ,nitrification1 effect (1 ^u bact]ia1 #ih4 ,odors1 removal (1 by filtration1 #aab4 ,organic matt]s 9 wat]1 #hc4 remov$ by int]mitt5t filt]s1 #ih4 ,pap] manufactur+1 filtration ( wat] =1 #e4 ,p>is1 gr\nd-wat] supply (1 #bgf4 ,palm]1 ,pr(41 #aca4 ,passages ?r\gh ! s& 9 filt]s1 #fg4 ,pegan ,brook1 purification (1 #aaj4 ,p]iod1 h[ comput$ & l5g? (1 #gb4 l5g? (1 dep5d5t ^u turbidity1 #acg4 ,piefke1 #dh1 #ej1 #ed1 #fc1 #fi1 #gc1 #gd1 #ge1 #hj1 #hd1 #he1 #ij4 ,pittsburgh1 exp]im5ts ) me*anical filt]s1 #afb4 ,plgge & ,proskau]1 #hd4 ,plym\?1 ,p5n41 typhoid fev] at1 #bjh4 ,pollution ( ,european wat]-supplies1 #ic4 ,pollut$ wat]s1 utilization ( excessively1 #aaa4 ,porcela9 filt]s = h\sehold use1 #ahc4 ,p\ghkeepsie1 ,n4 ,y41 filt]s at1 #bea4 ,pressure filt]s1 #ahj4 ,provid5ce1 me*anical filt]s at1 #aei4 ,rate ( filtration1 #dg1 #bbd4 at v>i\s places1 #bda4 effect (1 ^u co/1 #dh4 effect (1 ^u effici5cy1 #ej4 l[] aft] scrap+1 #gf4 regulation (1 #eb4 ,r$ ,bank1 ,n4 ,j41 filt]s at1 #aic1 #bec4 ,regulation ( filt]s1 #eb4 old =ms ( regulators1 #eb4 mod]n =ms ( regulators1 #ed4 at ,albany1 #cje1 #cjh1 #caj4 ( me*anical filt]s1 #agh4 ,re9cke1 ,dr41 report on heal? ( ,hamburg = #ahib1 #bbf4 ,re9s* on ! cause ( poor filtration at ,altona1 #bfg4 ,res]ve area requir$ 9 case ( ice1 #ah4 ,res]voirs1 purposes s]v$ by1 #acc4 ,rock ,isl&1 ,ill41 filt]s at1 #bed4 ,ro(s = filt]s1 #af4 ,rott]dam1 filt]s at1 #bgb4 ,/4 ,johnsbury1 ,vt41 filt]s at1 #bea4 ,/4 ,l\is1 regulators = propos$ filt]s1 #ee4 ,/4 ,pet]sburg1 filt]s at1 #bge4 ,samuelson1 #ea4 ,s&1 #bj4 at ,albany1 #cja4 analysis ( ,european1 #be4 analysis (1 f lead+ works1 #bh4 appliances = mov+1 #fh4 compactness (1 9 natural banks1 #fa4 dep? (1 9 filt]s1 #cd4 dep? to be remov$ f filt]s1 #fi4 dune1 #bf4 dune1 wa%+ (1 impossible1 #hb4 effect ( gra9-size ^u frequ5cy ( scrap+1 #cb4 effect ( gra9-size ^u ! effici5cy1 #cj4 effective size (1 #ba1 #bch4 extra scrap+ be=e replac+ fre%1 #ga4 = filtration1 #bj1 #cc4 = me*anical filt]s1 #age4 friction ( wat] 91 #bb4 gra9-size (1 #bj1 #bcc4 9 ,european filt]s1 #bd4 9 ,lawr5ce filt]s1 two sizes (1 #ajj4 lime 91 #bi4 me?od ( analysis (1 #bcc4 quantity to be remov$ by scrap+1 #gd4 replac+1 #ga4 selection (1 #cc4 size ( passages betwe5 gra9s (1 #f4 /]iliz$1 exp]im5ts )1 #he4 ?ickness ( lay]1 #cd4 uni=mity coeffici5t1 #ba1 #bch4 ,s& wa%+1 #bf1 #gf1 #cjd4 co/ (1 #ha4 wat] =1 #hj4 ,s&/one filt]s = h\sehold use1 #ahc4 ,s*i$am1 d\ble filtration at1 #bgc4 ,scrap+ filt]s1 #g1 #fh4 ,scrap+ filt]s1 am\nt ( labor requir$ =1 #ha4 dep? 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,art ( ,w> #hvo1 #d #jj ,metcalf's ,co/ ( ,manufactures--,& ! ,adm9i/ration ( ,work%ops #hvo1 #e #jj 99 ,ordnance & ,gunn]y4 #b vols #abmo1 #e #jj ,murray's ,infantry ,drill ,regulations #ahmo1 pap]1 #aj ,nixon's ,adjutants' ,manual #bdmo1 #a #jj ,peabody's ,naval ,ar*itecture #hvo1 #g #ej 99 ,phelps's ,practical ,m>9e ,survey+ #hvo1 #b #ej ,p[ell's ,army ,(fic]'s ,exam9] #abmo1 #d #jj ,%>pe's ,art ( ,subsi/+ ,armies 9 ,w> #ahmo1 morocco1 #a #ej 99 ,walke's ,lectures on ,explosives #hvo1 #d #jj 99 ,:eel]'s ,siege ,op]ations & ,milit>y ,m9+ #hvo1 #b #jj ,w9?rop's ,abridgm5t ( ,milit>y ,law #abmo1 #b #ej ,woodhull's ,notes on ,milit>y ,hygi5e #afmo1 #a #ej ,"y's ,simple ,elem5ts ( ,navigation #afmo1 morocco1 #b #jj ,,assay+4 ,flet*]'s ,practical ,in/ructions 9 ,quantitative ,assay+ ) ! ,bl[pipe #abmo1 morocco1 #a #ej ,furman's ,manual ( ,practical ,assay+ #hvo1 #c #jj ,lodge's ,notes on ,assay+ & ,metallurgical ,laboratory ,exp]im5ts #hvo1 #c #jj ,l['s ,te*nical ,me?ods ( ,ore ,analysis #hvo1 #c #jj ,mill]'s ,manual ( ,assay+ #abmo1 #a #jj ,m9et's ,production ( ,alum9um & its ,indu/rial ,use4 7,waldo47 #abmo1 #b #ej ,o',driscoll's ,notes on ! 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,cellulose ,molecule #abmo1 #b #ej 99 ,br[n+'s ,introduction to ! ,r>] ,elem5ts #hvo1 #a #ej ,bru% & ,p5field's ,manual ( ,det]m9ative ,m9]alogy #hvo1 #d #jj ,class5's ,quantitative ,*emical ,analysis by ,electrolysis4 7,boltwood47 #hvo1 #c #jj ,cohn's ,indicators & ,te/-pap]s #abmo1 #b #jj ,te/s & ,reag5ts #hvo1 #c #jj ,crafts's ,%ort ,c\rse 9 ,qualitative ,*emical ,analysis4 7,s*aeff]47 #abmo1 #a #ej ,dolezalek's ,!ory ( ! ,lead ,accumulator 7,/orage ,batt]y74 7,von ,ende47 #abmo1 #b #ej ,dre*sel's ,*emical ,reactions4 7,m]rill47 #abmo1 #a #be ,duhem's ,!rmodynamics & ,*emi/ry4 7,burgess47 #hvo1 #d #jj ,eissl]'s ,mod]n ,high ,explosives #hvo1 #d #jj ,effront's ,enzymes & _! ,applications4 7,prescott47 #hvo1 #c #jj ,erdmann's ,introduction to ,*emical ,prep>ations4 7,dunlap47 #abmo1 #a #be ,flet*]'s ,practical ,in/ructions 9 ,quantitative ,assay+ ) ! ,bl[pipe4 #abmo1 morocco1 #a #ej ,f[l]'s ,sewage ,works ,analyses #abmo1 #b #jj ,fres5ius's ,manual ( ,qualitative ,*emical ,analysis4 7,wells47 #hvo1 #e #jj ,manual ( ,qualitative ,*emical ,analysis4 ,"p ,i4 ,descriptive4 7,wells47 #hvo1 #c #jj ,sy/em ( ,in/ruction 9 ,quantitative ,*emical ,analysis4 7,cohn47 #b vols #hvo1 #ab #ej ,fu]tes's ,wat] & ,public ,heal? #abmo1 #a #ej ,furman's ,manual ( ,practical ,assay+ #hvo1 #c #jj 99 ,getman's ,ex]cises 9 ,physical ,*emi/ry #abmo1 #b #jj ,gill's ,gas & ,fuel ,analysis = ,eng9e]s #abmo1 #a #be ,grot5felt's ,pr9ciples ( ,mod]n ,dairy ,practice4 7,woll47 #abmo1 #b #jj ,hamm>/5's ,text-book ( ,physiological ,*emi/ry4 7,m&el47 #hvo1 #d #jj ,helm's ,pr9ciples ( ,ma!matical ,*emi/ry4 7,morgan47 #abmo1 #a #ej ,h]+'s ,ready ,ref]5ce ,tables 7,conv]sion ,factors7 #afmo1 morocco1 #b #ej ,h9d's ,inorganic ,*emi/ry #hvo1 #c #jj 99 ,laboratory ,manual = ,/ud5ts #abmo1 #a #jj ,holleman's ,text-book ( ,inorganic ,*emi/ry4 7,coop]47 #hvo1 #b #ej ,text-book ( ,organic ,*emi/ry4 7,walk] & ,mott47 #hvo1 #b #ej 99 ,laboratory ,manual ( ,organic ,*emi/ry4 7,walk]47 #abmo1 #a #jj ,hopk9s's ,oil-*emi/s' ,h&book #hvo1 #c #jj ,jackson's ,directions = ,laboratory ,"w 9 ,physiological ,*emi/ry #hvo1 #a #be ,keep's ,ca/ ,iron #hvo1 #b #ej ,ladd's ,manual ( ,quantitative ,*emical ,analysis #abmo1 #a #jj ,l&au]'s ,spectrum ,analysis4 7,t+le47 #hvo1 #c #jj 99 ,langwor?y & ,au/54 ,! 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7,a4 ,w47 & ,m>x's ,ma*9e ,design #hvo1 #c #jj ,spangl]1 ,gre5e1 & ,m>%all's ,elem5ts ( ,/eam-eng9e]+ #hvo1 #c #jj ,?ur/on's ,treatise on ,friction & ,lo/ ,"w 9 ,ma*9]y & ,mill ,"w #hvo1 #c #jj ,animal z a ,ma*9e & ,prime ,motor1 & ! ,laws ( ,en]getics #abmo1 #a #jj ,w>r5's ,elem5ts ( ,ma*9e ,con/ruction & ,draw+ #hvo1 #g #ej ,weisba*'s ,k9ematics & ,p[] ( ,transmission4 7,h]rmann--,kle947 #hvo1 #e #jj ,ma*9]y ( ,transmission & ,gov]nors4 7,h]rmann--,kle947 #hvo1 #e #jj ,wood's ,elem5ts ( ,analytical ,me*anics #hvo1 #c #jj ,pr9ciples ( ,elem5t>y ,me*anics #abmo1 #a #be ,turb9es #hvo1 #b #ej ,! ,_w's ,columbian ,exposition ( #ahic #dto1 #a #jj ,,metallurgy4 ,egle/on's ,metallurgy ( ,silv]1 ,gold1 & ,m]cury3 ,vol4 ,i4 ,silv] #hvo1 #g #ej ,vol4 ,,ii4 ,gold & ,m]cury #hvo1 #g #ej 9999 ,iles's ,lead-smelt+4 7,po/age #i c5ts additional47 #abmo1 #b #ej ,keep's ,ca/ ,iron #hvo1 #b #ej ,kunh>dt's ,practice ( ,ore ,dress+ 9 ,europe #hvo1 #a #ej ,le ,*ateli]'s ,high-temp]ature ,measurem5ts4 7,b\d\>d--,burgess47 #abmo1 #c #jj ,metcalf's ,/eel4 ,a ,manual = ,/eel-us]s #abmo1 #b #jj ,m9et's ,production ( ,alum9um & its ,indu/rial ,use4 7,waldo47 #abmo1 #b #ej ,rob9e & ,l5gl5's ,cyanide ,indu/ry4 7,le ,cl]c47 #hvo1 ,smi?'s ,mat]ials ( ,ma*9es #abmo1 #a #jj ,?ur/on's ,mat]ials ( ,eng9e]+4 ,9 ,?ree ,p>ts #hvo1 #h #jj ,"p ,,ii4 ,iron & ,/eel #hvo1 #c #ej ,"p ,,iii4 ,a ,treatise on ,brasses1 ,bronzes1 & ,o!r ,alloys & _! ,con/itu5ts #hvo1 #b #ej ,ulke's ,mod]n ,electrolytic ,copp] ,ref9+ #hvo1 #c #jj ,,m9]alogy4 ,b>r+]'s ,description ( ,m9]als ( ,comm]cial ,value4 ,oblong1 morocco1 #b #ej ,boyd's ,res\rces ( ,s\?we/ ,virg9ia4 #hvo1 #c #jj ,map ( ,s\?we/ ,virg9ia ,pocket-book =m1 #b #jj ,bru%'s ,manual ( ,det]m9ative ,m9]alogy4 7,p5field47 #hvo1 #d #jj ,*e/]'s ,catalogue ( ,m9]als #hvo1 pap]1 #a #jj ,clo?1 #a #be ,diction>y ( ! ,names ( ,m9]als #hvo1 #c #ej ,dana's ,sy/em ( ,m9]alogy ,l>ge #hvo1 half lea!r1 #ab #ej ,fir/ ,app5dix to ,dana's ,new 8,sy/em ( ,m9]alogy40 ,l>ge #hvo1 #a #jj ,text-book ( ,m9]alogy #hvo1 #d #jj ,m9]als & ,h[ to ,/udy ,!m #abmo1 #a #ej ,catalogue ( ,am]ican ,localities ( ,m9]als ,l>ge #hvo1 #a #jj ,manual ( ,m9]alogy & ,petrography #abmo1 #b #jj ,d\glas's ,unte*nical ,addresses on ,te*nical ,subjects #abmo1 #a #jj ,eakle's ,m9]al ,tables #hvo1 #a #be ,egle/on's ,catalogue ( ,m9]als & ,synonyms #hvo1 #b #ej ,hussak's ,! ,det]m9ation ( ,rock-=m+ ,m9]als4 7,smi?47 ,small #hvo1 #b #jj ,m]rill's ,non-metallic ,m9]als3 ,_! ,occurr5ce & ,uses #hvo1 #d #jj 99 ,p5field's ,notes on ,det]m9ative ,m9]alogy & ,record ( ,m9]al ,te/s4 #hvo1 pap]1 #ej ,ros5bus*'s ,microscopical ,physiography ( ! ,rock-mak+ ,m9]als4 7,idd+s47 #hvo1 #e #jj 99 ,tillman's ,text-book ( ,important ,m9]als & ,rocks #hvo1 #b #jj ,,m9+4 ,be>d's ,v5tilation ( ,m9es #abmo1 #b #ej ,boyd's ,res\rces ( ,s\?we/ ,virg9ia #hvo1 #c #jj ,map ( ,s\?we/ ,virg9ia ,pocket-book =m1 #b #jj ,d\glas's ,unte*nical ,addresses on ,te*nical ,subjects #abmo1 #a #jj 99 ,dr9k]'s ,tunnel+1 ,explosive ,comp\nds1 & ,rock ,drills #dto1 hf4 mor41 #be #jj ,eissl]'s ,mod]n ,high ,explosives #hvo1 #d #jj ,f[l]'s ,sewage ,works ,analyses #abmo1 #b #jj ,goodye>'s ,coal-m9es ( ! ,we/]n ,coa/ ( ! ,unit$ ,/ates #abmo1 #b #ej ,ihls5g's ,manual ( ,m9+ #hvo1 #e #jj 99 ,iles's ,lead-smelt+4 7,po/age #i;c4 additional47 #abmo1 #b #ej ,kunh>dt's ,practice ( ,ore ,dress+ 9 ,europe #hvo1 #a #ej ,o',driscoll's ,notes on ! treatm5t ( ,gold ,ores #hvo1 #b #jj ,rob9e & ,l5gl5's ,cyanide ,indu/ry4 7,le ,cl]c47 #hvo1 99 ,walke's ,lectures on ,explosives #hvo1 #d #jj ,wilson's ,cyanide ,processes #abmo1 #a #ej ,*lor9ation ,process #abmo1 #a #ej ,hydraulic & ,plac] ,m9+ #abmo1 #b #jj ,treatise on ,practical & ,!oretical ,m9e ,v5tilation #abmo1 #a #be ,,sanit>y ,,sci5ce4 ,ba%ore's ,sanitation ( a ,c\ntry ,h\se #abmo1 #a #jj ,folwell's ,sew]age4 7,design+1 ,con/ruction1 & ,ma9t5ance47 #hvo1 #c #jj ,wat]-supply ,eng9e]+ #hvo1 #d #jj ,fu]tes's ,wat] & ,public ,heal? #abmo1 #a #ej ,wat]-filtration ,works #abmo1 #b #ej ,g]h>d's ,guide to ,sanit>y ,h\se-inspection #afmo1 #a #jj ,goodri*'s ,economic ,disposal ( ,t[n's ,refuse ,demy #hvo1 #c #ej ,haz5's ,filtration ( ,public ,wat]-supplies #hvo1 #c #jj ,lea*'s ,! ,inspection & ,analysis ( ,food ) ,special ,ref]5ce to ,/ate ,control #hvo1 #g #ej ,mason's ,wat]-supply4 7,consid]$ pr9cipally f a ,sanit>y ,/&po9t7 #hvo1 #d #jj ,exam9ation ( ,wat]4 7,*emical & ,bact]iological47 #abmo1 #a #be ,ogd5's ,sew] ,design #abmo1 #b #jj ,prescott & ,w9sl['s ,elem5ts ( ,wat] ,bact]iology1 ) ,special ,ref]5ce to ,sanit>y ,wat] ,analysis #abmo1 #a #be 99 ,price's ,h&book on ,sanitation #abmo1 #a #ej ,ri*>ds's ,co/ ( ,food4 ,a ,/udy 9 ,diet>ies #abmo1 #a #jj ,co/ ( ,liv+ z ,modifi$ by ,sanit>y ,sci5ce #abmo1 #a #jj ,ri*>ds & ,woodman's ,air1 ,wat]1 & ,food f a ,sanit>y ,/&po9t #hvo1 #b #jj 99 ,ri*>ds & ,williams's ,! ,diet>y ,comput] #hvo1 #a #ej ,rideal's ,sewage & ,bact]ial ,purification ( ,sewage #hvo1 #c #ej ,turneaure & ,russell's ,public ,wat]-supplies #hvo1 #e #jj ,von ,behr+'s ,suppression ( ,tub]culosis4 7,bolduan47 #abmo1 #a #jj ,:ipple's ,microscopy ( ,dr9k+-wat] #hvo1 #c #ej ,w9ton's ,microscopy ( ,vegetable ,foods #hvo1 #g #ej ,woodhull's ,notes on ,milit>y ,hygi5e #afmo1 #a #ej ,,miscellane\s4 ,de ,fursac's ,manual ( ,psy*iatry4 7,rosan(f & ,coll9s47 ,l>ge #abmo1 #b #ej ,emmons's ,geological ,guide-book ( ! ,rocky ,m\nta9 ,excursion ( ! ,int]national ,congress ( ,geologi/s ,l>ge #hvo1 #a #ej ,f]rel's ,popul> ,treatise on ! ,w9ds #hvo1 #d #jj ,ha9es's ,am]ican ,railway ,managem5t #abmo1 #b #ej ,mott's ,fallacy ( ! ,pres5t ,!ory ( ,s\nd #afmo1 #a #jj ,ricketts's ,hi/ory ( ,r5ssela] ,polyte*nic ,in/itute1 #ahbd-ahid ,small #hvo1 #c #jj ,ro/oski's ,s]um ,diagnosis4 7,bolduan47 #abmo1 #a #jj ,ro!rham's ,emphasiz$ ,new ,te/am5t ,l>ge #hvo1 #b #jj ,/eel's ,treatise on ! ,diseases ( ! ,dog #hvo1 #c #ej ,! ,_w's ,columbian ,exposition ( #ahic #dto1 #a #jj ,von ,behr+'s ,suppression ( ,tub]culosis4 7,bolduan47 #abmo1 #a #jj ,w9sl['s ,elem5ts ( ,appli$ ,microscopy #abmo1 #a #ej ,worce/] & ,atk9son4 ,small ,hospitals1 ,e/abli%m5t & ,ma9t5ance2 ,sugge/ions = ,hospital ,ar*itecture3 ,plans = ,small ,hospital #abmo1 #a #be ,,hebrew ,,& ,,*aldee ,,text-,,books4 ,gre5's ,elem5t>y ,hebrew ,gramm> #abmo1 #a #be ,hebrew ,*re/oma?y #hvo1 #b #jj ,ges5ius's ,hebrew & ,*aldee ,lexicon to ! ,old ,te/am5t ,scriptures4 7,tregelles47 ,small #dto1 half morocco1 #e #jj ,lett]is's ,hebrew ,bible #hvo1 #b #be ,transcrib]'s ,notes3-- ,! ,to,c 7,table ( ,cont5ts7 has be5 *ang$ s z to foll[ ! /ructure ( ! book m fai?fully4 ,! orig9al ,to,c is giv5 "h3-- ,,cont5ts4 ,,page ,,*apt] ,i4 ,,introduction4 #a ,,ii4 ,,cont9u\s ,,filt]s ,,& ,,_! ,,con/ruction #e ,s$im5tation-bas9s #h ,size ( ,filt]-b$s #aj ,cov]s = ,filt]s #ab ,,iii4 ,,filt]+-,,mat]ials #bj ,s& #bj ,gravel #ce ,und]dra9s #ci ,dep? ( ,wat] on ,filt]s #de ,,iv4 ,,rate ,,( ,,filtration ,,& ,,loss ,,( ,,head #dg ,rate ( ,filtration #dg ,loss ( ,head & ,app>atus = regulat+ x #eb ,limit to ! ,loss ( ,head #fj ,v4 ,,clean+ ,,filt]s #fh ,scrap+ #fh ,frequ5cy ( ,scrap+ #gb ,s&-wa%+ #gf ,,vi4 ,,!ory ,,& ,,effici5cy ,,( ,,filtration #hc ,bact]ial ,exam9ation ( ,wat]s #ic ,,vii4 ,,int]mitt5t ,,filtration #ig ,! ,lawr5ce ,filt] #ajj ,! ,*emnitz ,filt] #ajg ,,viii4 ,,turbidity ,,& ,,color1 ,,& ,,! ,,effect ,,( ,,mud ,,^u ,,s& ,,filt]s #aac ,color #aad ,turbidity #aag ,prelim9>y ,processes to remove ,mud #acc ,effect ( ,mud ^u ,s& ,filt]s #acg ,,ix4 ,,coagulation ,,( ,,wat]s #add ,sub/ances us$ = ,coagulation #ade ,am\nt ( ,coagulant requir$ to remove ,turbidity #aej ,am\nt ( ,coagulant requir$ to remove ,color #aec ,successive ,applications ( ,coagulant #aed ,am\nt ( ,coagulant :i* ,wat]s w receive #aee ,x4 ,,me*anical ,,filt]s #aei ,influ5ce ( ,am\nt ( ,coagulant on ,bact]ial ,effici5cy #afe ,types ( ,me*anical ,filt]s #agb ,,xi4 ,,o!r ,,me?ods ,,( ,,filtration #aha ,,xii4 ,,removal ,,( ,,iron ,,f ,,gr\nd-,,wat]s #ahf ,cause ( ,iron 9 ,gr\nd-wat]s #ahg ,treatm5t ( ,iron-conta9+ ,wat]s #ahi ,iron-removal ,plants 9 ,op]ation #aib ,,xiii4 ,,treatm5t ,,( ,,wat]s #aig ,co/ ( ,filtration #bjj ,,xiv4 ,,wat]-,,supply ,,& ,,disease #baj ,,app5dix ,i4 ,,g]man ,,(ficial ,,regulation ,,9 ,,reg>d ,,to ,,filtration #bba ,,ii4 ,,extracts ,,f ,,dr4 ,,re9cke',s ,,report ,,^u ,,! ,,heal? ,,( ,,hamburg ,,= #ahib #bbf ,,iii4 ,,me?ods ,,( ,,s&-,,analysis #bcc ,,iv4 ,,/ati/ics ,,( ,,"s ,,filt]s #bda ,results ( ,op]ation #bda ,li/ ( ,s& ,filt]s 9 ,use #bdd ,li/ ( ,me*anical ,filt]s 9 ,use #bdg ,notes reg>d+ ,s& ,filt]s 9 ,am]ica #bea ,ext5t ( ! ,use ( ,filt]s #bed ,v4 ,,wat]-,,supply ,,( ,,london #bee ,,vi4 ,,wat]-,,supply ,,( ,,b]l9 #bfa ,,vii4 ,,wat]-,,supply ,,( ,,altona #bfe ,,viii4 ,,wat]-,,supply ,,( ,,hamburg #bfi ,,ix4 ,,notes ,,on ,,"s ,,o!r ,,european ,,supplies #bgb ,x4 ,,lit]ature ,,( ,,filtration #bgg ,,xi4 ,,! ,,albany ,,filtration ,,plant #bhh ,,index #cag ,9 ! table ( 8,,analyses ,,( ,,s&s ,,us$ ,,9 ,,wat] ,,filtration0 ! place "n 8,owe/y0 has be5 corre/$ to read 8,oswe/ry04 ,on page #bgj ! /atem5t 8! velocity 9 ! dra9 w rea* #j4ig foot0 %\ld probably read 8#j4ig feet p] second04