,transcriber's ,notes3 #a4 ,tildes are used to denote text in small caps4 ,,american ,,society ,,of ,,civil ,,engineers ,,instituted #aheb ,,transactions ,paper ,no4 #aaia ,,water ,,purification ,,plant1 ,,washington1 ,d4 ,c4 ,,results ,,of ,,operation4#a ,by ,e4 ,d4 ,hardy1 ,m4 ,am4 ,soc4 ,c4 ,e4 ,with ,discussion by ,messrs4 ,allen ,hazen1 ,george ,a4 ,johnson1 ,morris ,knowles1 ,george ,c4 ,whipple1 ,f4 ,f4 ,longley1 and ,e4 ,d4 ,hardy4 ,the ,washington filtration plant has already been fully described4#b ,at the time that paper was written 7,november1 #aijf71 the filtration plant had been in operation for only about #a year4 ,it has now been in continuous operation for #e years1 and many data on the cost1 efficiency1 and methods of operation1 have accumulated in the various records and books which have been kept4 ,it is thought that a brief review of the results1 and a summary of the records in tabular form1 will be of interest to the members of the ,society1 and it is also hoped that the discussion of this paper will bring out the comparative results of operation of other filter plants4 ,as a matter of convenience1 the following general description of the plant is given4 ,description of the ,filtration ,plant4--,the ,washington filtration plant was completed and put in operation in ,october1 #aije4 ,it consists of a pumping station for raising the water from the ,mc,millan ,park ,reservoir to the filter beds2 #bi filters of the slow sand type1 having an effective area of #a acre each2 the filtered-water reservoir1 having a capacity of about #ae1jjj1jjj gal42 and the necessary piping and valves for carrying water1 controlling rates of filtration1 etc4 ,footnote #a3 ,presented at the meeting of ,february #aeth1 #aiaa4 ,footnote #b3 ,works for the ,purification of the ,water ,supply of ,washington1 ,d4 ,c41 by ,allen ,hazen and ,e4 ,d4 ,hardy1 ,members1 ,am4 ,soc4 ,c4 ,e41 ,transactions1 ,am4 ,soc4 ,c4 ,e41 ,vol4 ,,lvii1 p4 #cjg4 ,in the pumping station1 there are three centrifugal pumps1 which are directly connected to tandem compound engines2 two sand-washer pumps2 three small electric generating sets for furnishing electric light2 and four #bjj-;h4p41 water-tube boilers4 ,each of the centrifugal pumps has a nominal capacity of #dj1jjj1jjj gal4 per day when pumping against a head of #ba ft41 and each sand-washer pump has a capacity of #b1ejj1jjj gal4 when pumping against a head of #bej ft4 ,the electric light engines and generators supply the current for lighting the pumping station1 the office and laboratory and other buildings1 and also the courts and interior of the filter beds1 and for operating a machine-shop4 ,the filters and filtered-water reservoir are built entirely of concrete masonry4 ,the floors are of inverted groined arches on which rest the piers for supporting the groined arch vaulting4 ,all this concrete work is similar to that in the ,albany1 ,philadelphia1 and ,pittsburg filters4 ,the filters contain1 on an average1 #dj in4 of filter sand and #ab in4 of filter gravel4 ,the gravel is graded from coarse to fine2 the lower and coarser part acts as part of the under-drain system1 and the upper and finest layer supports the filter sand4 ,the raw water from the pumps is carried to the filters through riveted steel rising mains which have #bj-;in4 cast-iron branches for supplying the individual filters4 ,the filtered water is collected in the under-drainage system of the several filter beds1 and is carried through #bj-;in41 cast-iron pipes to the regulator-houses4 ,these regulator-houses contain the necessary valves1 registering apparatus1 etc41 for regulating the rate of filtration1 showing the loss of head1 shutting down a filter1 filling a filter with filtered water from the under-drains1 and for turning the water back into the raw-water reservoir1 or wasting it into the sewer4 ,from the regulator-houses1 the filtered water flows directly to the filtered-water reservoir4 ,generally1 five filters are controlled from one house1 but there are two cases where the regulator-houses are smaller1 and only two filters are controlled from each4 ,the dirty sand removed from the filters is carried by a portable ejector through one or more lengths of #c-;in4 hose and a fixed line of #d-;in4 pipe1 to the sand washers4 ,from the sand washers1 the washed sand is carried to the reinforced concrete storage bins1 each of which has a capacity of #bej cu4 yd41 and is at such an elevation that carts may be driven under it and loaded through a gate4 ,until ,april1 #aiji1 the sand was replaced in the filters by carts which were filled through the gates in the sand bins4 ,it was then hauled to the top of the filter beds and dumped through the manholes on the chutes1 which could be revolved in any direction4 ,these chutes were used to prevent the sand from being unduly compacted in the vicinity of the manholes1 and to facilitate spreading it in the filters4 ,since ,april1 #aiji1 all the sand has been replaced by the hydraulic method4 ,an ejector is placed under the gate in the sand bin1 and the sand is carried in a reverse direction from the bin through the #d-;in4 piping and one or more lengths of hose to the filter bed4 ,this process has lowered the cost of re-sanding considerably1 and present indications are that it will prove entirely satisfactory in every way4 ,the average effective size and uniformity coefficient of the filters are shown in ,table #a4 ,table #a--;,filter ,sand as ,originally ,placed4 ,filter ,average ,average ,depth of ,average ,no4 effective size1 uniformity sand1 inturbidity4 in millimeters4coefficient4 inches4 ---------------------------------------- ------------ #a #j4cb #a4hh #ce4c #b1fjj #b #j4cj #a4gh #cg4g #b1bjj #c #j4cb #a4gg #dj4b #c1jjj #d #j4bi #a4hj #db4e #a1hjj #e #j4cd #a4gd #dd4i #b1gjj #f #j4ca #a4gh #cg4g #b1cjj #g #j4bi #a4gb #dj4a #b1cjj #h #j4cb #a4ge #dj4b #b1hjj #i #j4cb #a4gh #db4e #b1ijj #aj #j4cj #a4fi #ci4e #b1ejj #aa #j4cd #a4ic #cg4a #b1fjj #ab #j4bi #a4ff #cd4g #b1ajj #ac #j4cb #a4hc #cc4f #c1ejj #ad #j4bi #a4ff #cc4f #b1fjj #ae #j4cc #a4ge #ci4j #b1djj #af #j4cc #a4gh #db4c #c1jjj #ag #j4cc #a4hf #de4e #c1cjj #ah #j4cd #a4hj #dh4g #c1ajj #ai #j4cd #a4hj #eb4j 44444 #bj #j4cd #a4hg #ci4j #b1gjj #ba #j4cb #a4hb #db4c #b1djj #bb #j4cc #a4gd #de4e #b1bjj #bc #j4cc #a4ha #dh4g #b1cjj #bd #j4ce #a4hj #eb4j #b1fjj #be #j4bi #a4fd #ci4e #b1djj #bf #j4ca #a4ga #cg4a #b1ajj #bg #j4ca #a4ga #cd4g #a1ijj #bh #j4cc #a4ic #cc4f #b1cjj #bi #j4cd #a4ic #cc4f #c1jjj ---------------------------------------- ------------ ,maximum #j4cf #a4ic #eb4j #c1cjj ,minimum #j4bi #a4fd #cc4f #a1hjj ,average #j4cb #a4gg #dj4d #b1fjj ,description of ,washington ,aqueduct4--,the water supply of ,washington is taken from the ,potomac ,river1 at ,great ,falls1 about #af miles above the city4 ,at that place1 a dam has been built across the river1 which holds the water at an elevation of #aej4e ft4 above mean tide at ,washington4 ,from ,great ,falls the water flows by gravity for a distance of #af miles through a #i-;ft4 conduit1 three reservoirs1 and a tunnel4 ,from ,mc,millan ,park ,reservoir1 the last of the three1 the water is lifted by centrifugal pumps about #ba ft4 to the filters4 ,after passing through the filters1 it flows to the filtered-water reservoir1 and later to the city mains4 ,in its passage from ,great ,falls to the filters1 the water flows through three settling reservoirs1 which have already been referred to4 ,these reservoirs are known as the ,dalecarlia1 the ,georgetown1 and the ,mc,millan ,park ,reservoirs1 and have available capacities of #ada1jjj1jjj1 #adj1jjj1jjj1 and #ahj1jjj1jjj gal41 respectively4 ,turbidity4--,the ,potomac ,river water is rather turbid1 the turbidity being caused by very fine particles of clay4 ,the river is subject to sudden fluctuations1 it being no uncommon thing to have a turbidity of #ajj one day1 and #a1jjj the next4 ,the high turbidity usually disappears about as rapidly as it comes1 and is seldom higher than #ejj for more than #e days at a time4 ,it is frequently the case1 however1 that a succession of waves of high turbidity will appear so close together that the effect of one has not disappeared before that of another is felt4 ,the clarification of the water supply begins at the dam at ,great ,falls4 ,here it is a clarification by exclusion1 for when an excessive quantity of mud appears in the river water1 the gates are closed1 and the muddy water is allowed to flow over the dam and form mud-bars in the ,lower ,potomac1 while the city is supplied from the water stored in the three settling reservoirs4 ,until a comparatively recent date1 the excessively muddy water was never excluded1 having been taken1 like other decrees of ,providence1 as it came4 ,during the summer of #aijg1 the practice of shutting out water with a turbidity of #ejj or more was established for the warm months4 ,this practice was discontinued during the cold months1 as it was feared that a very high consumption of water might occur at the time of low water in the reservoirs1 and so cause a partial famine4 ,during the winter of #aiji-aj1 however1 the gates were closed1 as was the practice throughout the summer months4 ,when the reservoirs are well filled1 and the consumption of water is less than #gj1jjj1jjj gal4 per day1 it is safe to close the gates at ,great ,falls for a period of about #d days4 ,illustration3 ,figure #a--,plan and ,profile of ,washington ,aqueduct4 ,while a considerable reduction in turbidity is effected in each of the reservoirs1 the bulk of the mud is deposited at the upper end of ,dalecarlia ,reservoir4 ,this reservoir had become so completely filled1 that1 in #aije1 it was necessary to dredge a channel through the deposit1 in order to allow the water to pass it4 ,during the summers of #aijg and #aijh1 a #aj-;in4 hydraulic dredge removed more than #ajj1jjj cu4 yd4 of mud which had been deposited in this reservoir4 ,the mud deposited in ,georgetown and ,mc,millan ,park ,reservoirs is so fine that the accumulation of many years is not very noticeable in its effect on the depth of water4 ,the particles of clay which remain in the water after its passage through the three reservoirs1 are so exceedingly small that they do not settle out in any reasonable length of time4 ,even the filtration of the water through one or more slow sand filters occasionally fails to remove the last trace of turbidity4 ,this is especially true in the colder months1 and not a winter has passed when the water supply has not been noticeably turbid at some time4 ,a general idea of the quantity of mud contained in the river water1 the quantity excluded by closing the gates at ,great ,falls1 and that removed by sedimentation and filtration1 may be gained from ,table #b1 which is1 of course1 only a rough approximation4 ,table #b also shows that the gates were closed #aj4ej of the time1 thereby excluding #dj4jf of the total suspended matter which otherwise would have entered the system4 ,the turbidities1 bacterial counts1 and chemical analyses of numerous samples of water are shown in ,tables #c1 #d1 #e1 and #f4 ,the amount of work done in the pumping station1 average consumption of water1 death rate from typhoid fever1 and filter runs are shown in ,tables #g1 #h1 #i1 and #aj4 ,raking4--,at the time the filters were first put in service1 the sand bins had not been completed1 and1 consequently1 the work of cleaning the filters was carried on in the old-fashioned way of scraping by hand and wheeling out the sand in barrows4 ,this method of cleaning was used from ,october1 #aije1 to ,april1 #aijf2 then the regular sand-handling system was commenced4 ,at times1 during the first two summers the filters were in operation1 considerable difficulty was experienced in keeping them cleaned as fast as was necessary to provide an ample supply of filtered water4 ,for a short period in each summer it was found necessary to organize night shifts1 and keep the work of cleaning in progress for from #af to #bd hours per day4 ,illustration3 ,figure #b--;,general ,plan of ,washington ,filtration ,plant ,showing ,finished ,surfaces4 ,table #b--,tons of ,suspended ,matter ,entering ,system1 ,etc4 ,columns3 ,a - ,amount that would have entered the system if the gates had been left continuously open4 ,b - ,number of hours gates were closed4 ,c - ,amount shut out4 ,d - ,amount deposited in ,dalecarlia ,reservoir4 ,e - ,amount deposited in ,georgetown ,reservoir4 ,f - ,amount deposited in ,mc,millan ,park ,reservoir4 ,g - ,amount entering filtration plant4 ,month4 ,a ,b ,c ,d ,e ,f ,g ,total4 ---------------------------------------- -------------------- #aiji4 ---------------------------------------- -------------------- ,july #cah #cb4j #c #j #abe #gd #aaf #cah ,august #adf #dg4j #a #j #gh #ch #bi #adf ,september #ig #eg4j #g #ba #ac #ch #ah #ig ,october #fa #ij4e #h #g #i #be #ab #fa ,november #ej #fj4j #d #ac #e #ag #aa #ej ,december #cgj #ii4j #abf #ajh #cc #ei #dd #cgj ---------------------------------------- -------------------- #aiaj4 ---------------------------------------- -------------------- ,january #b1daj #acf4j #a1aji #a1jbj #fg #aag #ig #b1daj ,february #hci #aag4e #dha #abf #ef #ge #aja #hci ,march #bjh #g4e #ac #dc #ae #ac #abd #bjh ,april #cba #fe4j #ag #aie #dc #dc #bc #cba ,may #aig #hd4e #eh #ed #bb #bd #ci #aig ,june #a1eje #abd4j #ghf #ece #di #hh #dg #a1eje ---------------------------------------- -------------------- ,total #f1ebb #ibj4j #b1fac #b1abb #eae #faa #ffa #f1ebb ,in order to relieve the situation at such times1 the expedient of raking was tried4 ,this was first attempted with the filters filled with water2 the effluent was first shut off in order to prevent a downward flow of water1 and the filter was then raked or harrowed from boats4 ,this method was not satisfactory1 however1 as the work was neither as uniform nor as thorough as necessary4 ,later1 the filters were drained to the necessary depth1 and the surface of the sand was thoroughly stirred with iron garden rakes4 ,the filters were then filled with filtered water through the under-drains and put in service4 ,this latter method proved so satisfactory that it has been resorted to at all times when the work was at all pressing4 ,when the runs were of short duration1 and the depth to which the mud had penetrated the filter sand was slight1 a raking seemed to be nearly as effective in restoring the filter capacity as a scraping2 it could be done in #h hours by #c laborers1 and there seemed to be no ill effects from lowered efficiency4 ,table #c--,turbidities4 ,average by ,months4 7,united ,states ,geological ,survey ,standard47 ,reservoirs3 ---------------------------------------- -- ,month4 ,great ,falls4 ,dalecarlia ,georgetown ,mc,millan ,filtered ,outlet4 ,outlet4 ,park4 water4 ,outlet4 ---------------------------------------- --------- ,max4 ,ave4 ,max4 ,ave4 ,max4 ,ave4 ,max4 ,ave4 ,max4,ave ---------------------------------------- ------------------- #aije4 ---------------------------------------- ------------------- ,october #ajj #cf #dj #ba #cb #ah #bj #aa #d #a ,november #ce #ai #cd #ai #bb #ad #ad #aa #c #a ,december #a1ejj #aii #bej #hd #aej #gd #ie #ci #ad #f ---------------------------------------- ------------------- #aijf4 ---------------------------------------- ------------------- ,january #gjj #id #ahj #fj #abj #fj #he #eb #bj #ab ,february #abj #de #he #da #ee #bi #ce #bb #e #c ,march #a1gej #bgb #cej #aha #abj #ef #ij #df #h #f ,april #a1bgj #afg #ahj #gb #ie #eh #ge #df #ab #g ,may #fjj #ef #ej #bj #de #af #cd #aj #c #b ,june #a1gjj #cjc #ejj #abe #dej #id #ahj #da #ac #b ,july #a1jjj #acj #ahj #ed #aej #dg #bej #dc #ac #c ,august #a1ecj #cge #bej #aab #ie #ff #fe #de #e #b ,september #abj #cc #ahj #cd #ie #bh #ge #be #g #b ,october #a1jbe #abg #aaj #cg #fj #bd #ee #ba #a #a ,november #afj #bg #ge #bj #de #af #bd #ac #a #a ,december #fjj #fi #aaj #ca #hj #bh #hj #bf #h #b ---------------------------------------- ------------------- #aijg4 ---------------------------------------- ------------------- ,january #djj #ace #aej #gj #aaj #ge #gj #ec #aa #g ,february #ee #bf #bf #ae #cf #af #dj #ag #e #b ,march #iej #bdh #ahj #gg #acj #gj #ij #eg #g #d ,april #bjj #dg #hj #cc #fj #cj #de #bd #d #b ,may #acj #bi #dj #ah #bf #ae #ad #i #a #a ,june #djj #ajd #afj #dh #ge #cb #dj #ah #a #a ,july #fjj #aad #acj #fa #gh #dg #de #ca #a #a ,august #hjj #gc #acj #ce #he #bf #cj #ad #a #j ,september #fjj #abi #a #a #aej #ea #gj #bh #a #j ,october #ge #cb #a #a #fe #bh #ge #bf #d #j ,november #cjj #ig #a #a #ajj #de #de #bc #b #a ,december #fhj #ace #a #a #ahj #fa #ajj #df #aj #d ---------------------------------------- ------------------- #aijh4 ---------------------------------------- ------------------- ,january #b1ajj #bjb #cdj #gc #bej #hb #afj #fe #bj #g ,february #c1jjj #cjb #cjj #eb #aej #eb #ge #cb #g #d ,march #cjj #ia #aej #gh #ajj #fh #fe #db #e #d ,april #ge #bc #fe #da #cg #bg #bf #bj #c #b ,may #b1jjj #agb #acj #dh #he #cg #ej #bj #a #a ,june #djj #dj #gj #bi #dj #bd #cj #ah #a #a ,july #a1ejj #adi 444 #gd #agj #dd #ge #ae #j #j ,august #ijj #abi #bjj #a #aej #ef #he #ci #b #a ,september #ge #bd #a #a #ej #ai #ce #ah #j #j ,october #ie #bj #a #a #ee #ah #bh #ae #j #j ,november #bd #aa #a #a #bj #aa #ai #aj #j #j ,december #bj #i #ag #aa #ad #i #aj #g #j #j ---------------------------------------- ------------------- #aiji4 ---------------------------------------- ------------------- ,january #djj #gb #ie #cb #fj #bc #be #af #d #a ,february #fej #aid #abj #fd #ij #ea #ee #ce #d #c ,march #bej #ea #a #a #ij #dd #fj #cg #h #d ,april #gej #ih #a #a #acj #db #gf #ca #b #a ,may #dhj #eg #a #a #cj #ai #cj #ab #b #a ,june #fej #ada #a #a #abj #ea #hj #cj #a #j ,july #djj #dh #a #a #bae #df #abj #ce #b #a ,august #ahj #bc #a #a #ej #ag #ah #i #j #j ,september #bf #af #bd #ad #a #a #be #f #j #j ,october #ad #aj #ae #aj #aa #i #h #d #j #j ,november #aa #i #aa #h #aj #h #f #d #j #j ,december #fjj #fc #aaj #ca #hj #bh #ej #ae #c #j ---------------------------------------- ------------------- #aiaj4 ---------------------------------------- ------------------- ,january #c1jjj #ceg #bjj #eh #aej #ec #aae #cj #e #b ,february #c1jjj #adc #aej #ee #abj #ej #ajj #cf #g #d ,march #baj #cf #ajj #ce #ie #ch #ajj #dc #i #e ,april #cej #ee #ajj #be #ee #ah #be #h #a #jb ,may #cjj #cc #ee #ai #ej #ag #bh #ac #a #jb ,june #a1ejj #bdf #ahj #db #aaj #cg #ej #af #a #jb ---------------------------------------- ------------------- ,fiscal years3 ---------------------------------------- ------------------- #aije-jfba1gej #acc #ejj #gj #dej #dg #ahj #ca #bj #e #aijf-jg #a1ecj #aad #bej #df #aej #cg #bej #bi #ac #b #aijg-jh #c1jjj #aag #cdj #ec #bej #de #afj #ca #bj #b #aijh-ji #a1ejj #gi #bjj #ej #agj #cb #he #bb #h #a #aiji-aj #b1ajj #hf #bjj #cj #bae #bi #abj #ah #i #a ,footnote #a3 ,reservoirs out of service4 ,footnote #b3 ,october to ,june #cjth4 ,table #d--;,bacteria4 ,averages by ,months4 ,reservoirs3 ---------------------------------------- ----------- ,month4 ,dalecarlia,dalecarlia,georgetown,mc,mil lan ,park,filtered ,inlet4 ,outlet4 ,outlet4 ,outlet4 water4 ---------------------------------------- ------------------------ #aije4 ---------------------------------------- ------------------------ ,october 444 444 444 #baj #hj ,november 444 444 444 #aej #bg ,december 444 #ae1ejj 444 #c1hjj #fj ---------------------------------------- ------------------------ #aijf4 ---------------------------------------- ------------------------ ,january 444 #b1hjj 444 #a1ejj #ci ,february #b1ijj #d1ajj #a1hjj #eej #af ,march #a1hjj #a1ajj #ijj #fej #ai ,april #c1cjj #a1gjj #gjj #djj #bb ,may #dbe #baj #ie #fe #ag ,june #g1ijj #d1fjj #cbe #bbj #ag ,july #ac1ejj #fjj #dge #afj #bf ,august #h1gjj #a1ajj #a1bjj #aij #ad ,september #dbe #bej #adj #ace #ad ,october #b1cjj #iej #fej #bgj #af ,november #a1hjj #a1ajj #a1bjj #bbj #ab ,december #f1ijj #c1hjj #c1fjj #gjj #de ---------------------------------------- ------------------------ #aijg4 ---------------------------------------- ------------------------ ,january #d1djj #b1djj #b1bjj #iej #gj ,february #a1jjj #iej #a1jjj #gjj #de ,march #aa1ejj #h1cjj #g1bjj #c1fjj #fe ,april #c1gjj #b1ajj #a1djj #dge #ba ,may #gej #cej #cbe #acj #bf ,june #b1cjj #a1jjj #fjj #ajj #ah ,july #b1gjj #ege #cej #afj #ag ,august #c1jjj #bge #dbe #hj #ag ,september #f1bjj #a #a1ijj #bcj #cb ,october #a1djj #a #iej #bge #bg ,november #h1ijj #a #f1fjj #a1ejj #bg ,december #af1jjj #a #i1fjj #d1cjj #aij ---------------------------------------- ------------------------ #aijh4 ---------------------------------------- ------------------------ ,january #aa1jjj #h1gjj #i1djj #c1gjj #aij ,february #aa1ejj #f1jjj #e1jjj #b1hjj #ge ,march #d1fjj #d1jjj #b1ijj #a1cjj #cj ,april #gjj #dej #bej #abj #ac ,may #i1ejj #a1ajj #fej #cbe #ag ,june #gej #abj #aaj #ie #ab ,july #d1ijj 444 #djj #aej #h ,august #a1fjj #cbe #cjj #ajj #ab ,september #cbe #a #bjj #hj #aa ,october #cge #a #cbe #adj #h ,november #eej #a #cjj #bjj #ab ,december #hjj #gej #cge #agj #bc ---------------------------------------- ------------------------ #aiji4 ---------------------------------------- ------------------------ ,january #aa1jjj #b1gjj #a1fjj #gjj #ca ,february #h1jjj #c1ejj #b1djj #a1cjj #fj ,march #c1hjj #a #b1fjj #a1jjj #ci ,april #b1bjj #a #a1djj #eej #ab ,may #ijj #a #cej #adj #af ,june #c1djj #a #a1bjj #agj #ba ,july #eej #a #ejj #bej #cc ,august #djj #a #cbe #ee #ah ,september #cbe #bdj #a #gj #ah ,october #cej #bge #bej #acj #bj ,november #fjj #ejj #ejj #ahj #ac ,december #ba1jjj #i1ajj #e1ijj #d1ejj #bej ---------------------------------------- ------------------------ #aiaj4 ---------------------------------------- ------------------------ ,january #gf1jjj #gh1jjj #hh1jjj #eb1jjj #hjj ,february #de1jjj #ce1ejj #ca1jjj #ag1ejj #cej ,march #i1ijj #g1fjj #g1djj #d1hjj #hj ,april #g1ijj #d1ajj #c1ejj #fej #bi ,may #a1bcj #haj #hcj #ddh #bh ,june #c1ffj #icj #hjj #cbd #bg ---------------------------------------- ------------------------ ,fiscal years3 ---------------------------------------- ------------------------ #aije-jf #c1cjjb #d1cjjc #gejd #hejb #ccb #aijf-jg #d1ijj #a1ijj #a1gjj #fej #ca #aijg-jh #f1cfj #b1gjj #b1ijj #a1cjj #ee #aijh-ji #c1djj #b1jjj #iej #djj #ba #aiji-aj #ad1cjj #ac1ijj #aj1ijj #f1hij #adc ,footnote #a3 ,reservoirs out of service4 ,footnote #b3 ,october to ,june #cjth4 ,footnote #c3 ,december to ,june #cjth4 ,footnote #d3 ,february to ,june #cjth4 ,table #e--,results of ,tests for ,bacillus ,coli4 ,percentage ,positive4 ,great ,falls1 ,dalecarlia or ,dalecarlia ,reservoir ,georgetown ,reservoir ,outlet4 ,reservoir4 ,month4 ,inlet4 ------------------------------------- #aj #a #j4a #aj #a #j4a #aj #a #j4a c4c4c4c4c4c4c4c4c4c4c4c4c4c4c4c4c4c4 ---------------------------------------- ---------- #aijf4 ---------------------------------------- ---------- ,january#a #ee4fch4ibb4bfi4bbc4a #g4gef4jdj4j #h4j ,february #cc4cbf4g #f4gbf4aag4d #h4gcj4dac4j #d4d ,march #ej4jab4e #jde4eah4b #jbj4h #h4c #j ,april #gb4bcc4caf4gie4eej4j #d4fei4abb4g #d4f ,may #bj4j #h4j #d4jbj4jab4j #j #g4h #j #j ,june #eg4gch4eai4bdj4jcb4j #h4jej4jcd4f #j ,july #fe4jej4j #e4jfj4jbe4jaj4jae4j #e4j #e4j ,august #hd4ffi4bfa4ehh4efe4dcd4fhj4jeg4gbc4a ,september #ej4jaj4j #jcj4jaj4jaj4jdj4jaj4j #j ,october #fj4jcj4jaj4jee4ecc4c #jhj4jfj4jbj4j ,november #cg4e #j #jbe4jab4eab4ecg4ebe4j #j ,december #ee4edd4e #jff4gdd4ebb4bff4gbb4b #j ---------------------------------------- ---------- #aijg4 ---------------------------------------- ---------- ,january #gg4hcc4cbb4bff4gcc4c #jee4eee4ebb4b ,february #cg4ebe4j #jab4e #j #jcg4eab4e #j ,march #hg4eej4j #jge4jcg4e #jej4jbe4j #j ,april #dd4eaa4aaa4aff4gbb4baa4agg4haa4aaa4a ,may #ia4cfe4bag4dhh4icc4c #jhg4eej4jab4e ,june #hj4jfh4jbd4jhg4efb4e #jff4gdd4eaa4a ,july #db4ccj4hai4bbe4jab4e #jbb4bbb4b #j ,august #dh4abi4f #c4gcc4caf4gaf4gcf4dah4b #j ,september #fb4eed4abe4j 444 444 444#da4gcc4caf4g ,october #ea4idj4h #g4d 444 444 444#ec4cdj4j #f4g ,november #hj4jfd4jbd4j 444 444 444#gb4ged4e #j ,december #ef4jdh4jaf4j 444 444 444#df4bch4e #g4g ---------------------------------------- ---------- #aijh4 ---------------------------------------- ---------- ,january #df4bcj4hae4dej4jab4e #jcc4c #j #j ,february #ab4e #j #jbe4j #j #jab4e #j #j ,march #ch4eai4b #g4gdd4daa4a #jaa4a #j #j ,april #ae4d #g4g #j #j #j #j #j #j #j ,may #gf4jeb4jdj4jhg4eej4jab4ecc4cbb4b #j ,june #g4g #j #j #j #j #jaa4a #j #j ,july #bf4iae4daa4ebb4bbb4b #jaa4a #j #j ,august #df4bbf4i #c4idd4dcc4c #jfb4ebe4jab4e ,september #bj4j #h4j #d4jdb4ibh4f #a4dbb4baa4a #j ,october #ah4d #c4g #j #j #j #j #i4a #j #j ,november #ac4j #j #jbh4f #j #jaa4a #j #j ,december #aa4e #g4g #c4h #j #j #jab4e #j #j ---------------------------------------- ---------- #aiji4 ---------------------------------------- ---------- ,january #ab4j #h4j #jcj4jaj4j #j #j #j #j ,february #eb4adg4hdg4hbh4fad4c #jcg4e #j #j ,march #fi4dcd4f #c4hej4jbe4j #jdd4eaa4a #j ,april #db4cae4d #c4icc4cbb4baa4add4dbb4baa4a ,may #hh4dbf4a #d4cej4jab4e #jcc4c #j #j ,june #he4jfj4jbe4jfj4jdj4jaj4jdd4dcc4caa4a ,july #cd4h #h4g #d4d 444 444 444#cc4caa4a #j ,august #ej4jae4d #g4g 444 444 444#dj4jaj4j #j ,september #dc4eba4h #h4gbe4jbe4jab4e #j #j #j ,october #cf4dac4f #jah4b #j #j #j #j #j ,november #d4e #j #jaj4j #j #j #j #j #j ,december #ch4ebc4a #g4gcf4dcf4dah4bcc4cbb4baa4a ---------------------------------------- ---------- #aiaj4 ---------------------------------------- ---------- ,january #gb4jdh4jbd4jdd4ecc4caa4age4jbe4j #j ,february #dg4hdc4eag4dfc4bba4a #e4cdj4jcj4j #e4j ,march #cc4cad4h #jcj4haa4a #c4gbi4fbb4b #g4d ,april #da4gcc4cbj4hdj4jcb4jaf4jch4ebc4aae4d ,may #dg4hag4d #jeb4jbj4j #jcf4jaf4j #d4j ,june #ie4ehf4dca4hhj4hdf4bai4bfd4jbh4j #h4j ---------------------------------------- --------- ,fiscal years3 ---------------------------------------- ---------- #aije-jf #ce4bai4di4c #j4j #c4b #e4b #f4d #d4i #a4g #aijf-jg #fa4edc4fi4b #g4g #i4b #b4c #a4a #i4h #j4g #aijg-jh #dd4fca4cc4j #b4c #b4c #c4a #d4d #b4a #d4a #aijh-ji #ch4ibj4ch4d #j4j #e4j #j #g4d #h4e #b4h #aiji-aj #de4ebf4ij4a #e4c #d4j #h4h #g4i #i4h #f4b ,mc,millan ,park ,filtered-,tap water ,reservoir water from var- 7applied reser- ious parts ,month4 water74 voir4 of city4 ----------------------------- #aj #a #j4a #aj #a #aj #a c4c4c4c4c4c4c4c4c4c4c4c4c4c4 ---------------------------------------- -- #aijf4 ---------------------------------------- -- ,january#a #ee4fbb4b #j #g4b #j 444 444 ,february #h4c #d4b #j #j #j 444 444 ,march #ah4e #g4dc4g #j #j #j #j ,april #cb4j #h4j #j #d4j #j #j #j ,may #j #j #j #j #j #j #j ,june #bc4a #g4gc4h #j #j #c4a #j ,july #i4e #j #j #d4h #j 444 444 ,august #fc4jcc4c #j #g4d #c4gaa4i #e4a ,september #cb4jab4j #j #h4j #j #c4a #j ,october #dh4abb4bc4g #c4g #jac4j #c4g ,november #bj4jab4j #j #h4j #j #j #j ,december #bj4h #h4cd4b #af4g #h4c #g4e #j ---------------------------------------- -- #aijg4 ---------------------------------------- -- ,january #fi4ccd4fc4h #ai4baa4ead4j #j ,february #ag4d #d4d #j #j #j #b4i #j ,march #cj4h #g4g #j #j #j #b4a #j ,april #df4aai4bc4h #c4h #j #c4b #j ,may #bc4a #j #j #j #j #a4d #j ,june #dj4j #h4j #j #j #j #j #j ,july #c4h #j #j #j #j #a4d #a4d ,august #ad4h #c4g #j #j #j #j #j ,september #af4j #d4j #j #d4j #j #a4g #j ,october #ch4gbe4hi4g #f4e #jab4e #b4h ,november #eh4fag4cc4e #j #j #d4i #j ,december #de4bbi4j #j #ai4c #c4bab4i #d4c ---------------------------------------- -- #aijh4 ---------------------------------------- -- ,january #bb4f #i4gc4b #c4b #j #a4i #a4i ,february #j #j #j #j #j #j #j ,march #i4g #j #j #j #j #j #j ,april #f4g #c4c #j #j #j #j #j ,may #de4aaf4b #j #j #j #j #j ,june #j #j #j #j #j #j #j ,july #f4d #f4d #j #j #j #j #j ,august #ab4i #c4b #j #j #j #a4f #j ,september #af4gaj4j #j #j #j #d4c #j ,october #i4g #f4dc4b #j #j #j #j ,november #f4f #j #j #j #j #j #j ,december #c4b #j #j #j #j #j #j ---------------------------------------- -- #aiji4 ---------------------------------------- -- ,january #c4b #c4b #j #c4b #j #j #j ,february #g4a #c4fc4f #j #j #c4d #c4d ,march #cb4cai4dc4b #f4e #j #b4h #a4d ,april #cf4faj4j #j #j #j #j #j ,may #ab4i #c4b #j #j #j #j #j ,june #ec4cbj4j #j #j #j #a4d #j ,july #be4hab4i #j #j #j #j #j ,august #bb4f #f4e #c4b #j #j #j #j ,september #ac4c #c4c #j #j #j #j #j ,october #c4b #j #j #j #j #j #j ,november #j #j #j #j #j #j #j ,december #bi4jbb4f #j #i4g #f4e #g4c #a4e ---------------------------------------- -- #aiaj4 ---------------------------------------- -- ,january #fa4cce4ei4g #e4h #c4bae4i #c4b ,february #cb4b #g4a #j #c4f #j #j #j ,march #ab4i #c4b #j #j #j #j #j ,april #bc4cac4c #j #j #j #j #j ,may #af4aab4i #j #j #j #j #j ,june #dc4c #f4g #j #j #j #a4d #j ---------------------------------------- -- ,fiscal years3 ---------------------------------------- -- #aije-jf #d4c #h4c 4#h 4#c #a4h #a4c #j #aijf-jg #b4e #c4j 4#d 4#e #b4a #e4d #a4j #aijg-jh #b4b #i4d 4#d 4#h #j4c #c4a #j4i #aijh-ji #f4g #g4a 4#h 4#h #j #a4b #j4d #aiji-aj #c4f #j4d 4#a 4#c #j4h #b4b #j4d ,footnote #a3 ,presumptive tests4 ,table #f--,summary of ,sanitary ,chemicals ,analyses of ,weekly ,samples1 ,july #ast1 #aiji1 to ,june #cjth1 #aiaj4 7,results in ,parts per ,million47 ,columns3 ,a - ,turbidity#a ,b - ,free ,c - ,albuminoid ,d - ,total ,e - ,nitrites ,f - ,nitrates ,g - ,hardness ,h - ,alkalinity ,i - ,chlorine 7,a7 ,maximum4 ,ammonia4 ,nitrogen as3 ,reservoirs4 ,a -------------------------- ,g ,h ,i ,b ,c ,d ,e ,f ---------------------------------------- ------------------------ ,dalecarlia inlet #b1ajjj4jcdj4bfdj4bhjj4jjgjj4deabj4jajf4 je4d ,dalecarlia outlet#b #bjjj4jcdj4ahjj4bjfj4jjejj4gjaae4jaje4he 4g ,georgetown outlet#c #baej4jcjj4ahbj4ahbj4jjfjj4fjaae4jaje4jd 4i ,mc,millan ,park outlet #abjj4jbhj4abfj4aedj4jjfjj4feaah4jajd4dd 4b ,filtered water #ij4jafj4jghj4jhfj4jjajj4gjaai4eajf4cd4e ---------------------------------------- ----------------------- ,table #f--7;,continued47 7,b7 ,minimum4 ,ammonia4 ,nitrogen as3 ,reservoirs4 ,a -------------------------- ,g ,h ,i ,b ,c ,d ,e ,f ---------------------------------------- ------------------------ ,dalecarlia inlet #gj4jjjj4jafj4jafj4jjjjj4jj #eb4i #ci4e #a4j ,dalecarlia outlet#b #gj4jjjj4jdjj4jdjj4jjjjj4jj #ed4c #ch4b #j4i ,georgetown outlet#c #gj4jjjj4jddj4jddj4jjjjj4jj #ea4d #dj4f #j4g ,mc,millan ,park outlet #bj4jjjj4jajj4jajj4jjajj4jj #ea4d #ch4e #j4b ,filtered water #jj4jjjj4jjjj4jjjj4jjjjj4jj #eb4i #dj4c #j4d ---------------------------------------- ------------------------ ,table #f--7;,continued47 7,c7 ,average4 ,ammonia4 ,nitrogen as3 ,reservoirs4 ,a -------------------------- ,g ,h ,i ,b ,c ,d ,e ,f ---------------------------------------- ------------------------ ,dalecarlia inlet #hf #j4jjfj4afgj4aacj4jjbgj4ai #ic4b #ha4d #b4i ,dalecarlia outlet#b #cj #j4jjhj4ajfj4aadj4jjbcj4ah #ie4e #gi4e #c4d ,georgetown outlet#c #bi #j4jjej4ajaj4ajfj4jjbgj4ah #ic4d #hj4i #b4i ,mc,millan ,park outlet #ah #j4jjdj4jggj4jhaj4jjbgj4ag #id4j #hc4j #b4g ,filtered water #a #j4jjbj4jbgj4jbij4jjjjj4ai #id4i #hd4j #b4h ,footnote #a3 ,summary of daily samples of water4 ,footnote #b3 ,reservoir out of service from ,july #ast to ,september #acth1 #aiji4 ,footnote #c3 ,reservoir out of service from ,september #ajth to ,october #dth1 #aiji4 ,no chemical determinations were made during ,february1 ,march1 ,april1 and ,may1 #aiaj1 on account of the rearrangement of the laboratory and equipment4 ,table #g--;,daily ,results at ,pumping ,station4 7,a7 ,million gallons pumped3 ,pressure ---------------------------------- at sand- ,lift washer ,to filters4 ,to sand washers4 to pumps1 ,month4 filters4 per ------------------------------ square ,max4 ,min4,ave4 ,max4 ,min4 ,ave4 inch4 ---------------------------------------- --------------------- #aiji4 ---------------------------------------- --------------------- ,july #gf4afeg4fefd4jea4adjj4bihj4gcj #bd4ah #aaj4j ,august #fi4caed4ddfa4dbj4fbij4aegj4dda #bb4ah #aaj4j ,september #ff4jbeb4hbfi4cbj4hcaj4bjgj4egb #bb4bf #aaj4j ,october #gh4ejdh4abei4ahj4gfaj4jfjj4dfg #ba4hd #aaj4j ,november #fd4ibdi4hcee4bej4dfhj4adaj4bgb #bj4di #aaj4j ,december #fg4hcdh4cbef4ggj4cjgj4jcij4agd #bj4ed #aaj4j ---------------------------------------- --------------------- #aiaj4 ---------------------------------------- --------------------- ,january #gj4jdea4jbfb4dij4diij4jjhj4aef #bb4dc #aaj4j ,february #gj4giee4aifj4bhj4bhdj4jdaj4agc #ba4dd #aab4c ,march #ei4aaea4fdef4jdj4djij4jfcj4aga #ai4gf #abj4j ,april #ff4ecec4gieh4cbj4gaej4afgj4dgd #bj4gh #abj4j ,may #fa4iced4eeeg4gfj4ebej4jeij4bea #bj4cj #abj4j ,june #gj4diej4dbeh4cgj4bhaj4abdj4bjg #ba4ai #aag4c ---------------------------------------- --------------------- ,fiscal years3 ---------------------------------------- --------------------- #aiji-aj #gh4ejdh4abei4aia4adjj4jjhj4cgc #ba4de #aac4c ---------------------------------------- --------------------- #aije-jfa #hj4eieg4ahff4jgb4jfbj4jhij4gdg #ba4ga #ajg4d #aijf-jg #hj4bieg4ddff4hib4abjj4jbcj4ehj #ba4fj #abj4h #aijg-jh #hj4ched4cefd4iaj4gcej4jagj4cdg #bb4bj #abe4j #aijh-ji #gh4icdg4hcfa4dgj4hgej4jfjj4dec #bb4eb #abb4c ---------------------------------------- --------------------- ,coal consumed,station duty1 per day in per #ajj lb4 of ,month4 tons4 coal consumed4 ------------------------- ,max4,min4,ave4,max4,min4,ave4 -------------------------------------- #aiji4 -------------------------------------- ,july #ac4d #h4daj4hfg4heb4cfa4d ,august #ab4d #h4jaj4afd4bdi4eef4f ,september #ab4g #h4gaj4efa4jdh4iee4a ,october #ac4d #h4jaj4cei4fdi4aec4f ,november #aa4c #g4i #i4bee4fde4gea4a ,december #aj4c #h4e #i4efa4jde4dej4d -------------------------------------- #aiaj4 -------------------------------------- ,january #ab4g #i4aaj4dei4fdi4hed4i ,february #ab4c #h4gaj4beg4ddd4hea4e ,march #aj4e #g4h #i4bec4bde4bdi4h ,april #aa4a #h4a #i4geh4gdg4bec4g ,may #aj4a #g4d #h4hfj4gdh4aed4i ,june #ab4c #g4d #i4afj4adi4ied4d -------------------------------------- ,fiscal years3 -------------------------------------- #aiji-aj #ac4d #g4d #i4hfg4hdd4hed4j ------------------------------------- #aije-jfa #ad4h #f4d #h4igi4fdh4bfb4h #aijf-jg #ae4j #g4jaj4jga4fdf4eeh4f #aijg-jh #ab4j #g4bi4f #gj4gea4cfj4c #aijh-ji #ac4b #g4jaj4jgd4jde4geg4g ------------------------------------- ,footnote #a3 ,raw water shut off from city supply on ,october #eth4 ,table #g--7;,continued47 7,b7 ,duty per ,cost of #ajj lb4 coal per ,fiscal ,name of coal used4 ,cost per of coal #a1jjj1jjj ft- ,year4 ton4 consumed4lb4 of work performed ---------------------------------------- ----------------------- #aije-jf ,george's ,creek ,big ,vein #c4cd #fb4h #j4jjbch #aijf-jg ,george's ,creek ,big ,vein #c4dc #eh4f #j4jjbfa #aijg-jh ,george's ,creek ,big ,vein #c4ge #fj4c #j4jjbgh #aijh-ji ,orenda #c4dg #eg4g #j4jjbfh #aiji-aj ,orenda #ac4ae #ed4j #j4jjbee ,footnote #a3 ,corrected for increase or decrease in ash and ,british thermal units1 as determined by ,united ,states ,geological ,survey4 ,table #h--;,average ,consumption of ,water for ,twenty-four ,hours1 ,per ,million ,gallons4 ,fiscal years4 ,month4 ---------------------------------------- - #aijc4aijd4aije4aijf4aijg4aijh4aiji4aiaj 4 ---------------------------------------- ----------- ,july #ei4hjfa4ejfc4bjfi4hjfi4ahfh4fdga4jhfd4j e ,august #ei4jjei4gjfg4gjga4djfh4jcfg4gdfh4adfa4d b ,september #ef4ejfa4ajfg4ijga4cjfi4hbfh4icfe4hcfj4c b ,october #eh4gjei4ajfc4ijfh4djfi4adff4dffe4hiei4a h ,november #ed4gjeh4fjfb4ajff4ajfe4eafa4edfj4jfee4b e ,december #fj4gjfj4ajgj4cjfg4bjfe4gafb4bieg4iief4g g ,january #fj4ajfe4cjge4ajfe4cjfg4fbfc4cfeg4gbfb4d i ,february #ei4cjfg4hjhf4jjfh4gjgd4fhfh4agee4dbfj4b h ,march #ee4cjfj4jjfg4fjfd4cjfd4bcei4fcee4caef4j d ,april #ee4ajeg4bjfc4ajfb4gjfc4defa4eaeh4aieh4c b ,may #eg4gjfj4hjff4cjfe4fjfb4dgfb4ifei4beeg4g f ,june #ei4ejfb4cjgj4fjfg4hjfc4ecfg4iffj4abeh4c g ---------------------------------------- ----------- ,average #eh4jcfa4ajfh4gjfg4djff4ijfd4iafa4dgei4a i ,the length of runs1 depth of scraping1 etc41 after the scraping or raking1 are shown in ,tables #aj and #aa4 ,sand ,handling4--,for the first three years of operation1 the sand was carried from the sand bins in carts and dumped through the numerous manholes of the filters on chutes which could be revolved in various directions1 in order to facilitate the spreading of the sand evenly over the surface of the filter4 ,about a year ago1 however1 this method was changed1 by substituting sand ejectors for the carts4 ,by this method1 an ejector is either attached to1 or placed directly under1 the outlet gate of the sand bin1 the gate is opened1 and the ejector is started4 ,from this ejector1 the sand is carried back through the line of #d-;in4 fixed pipe1 and one or more lengths of #c-;in4 hose1 to the point of discharge in the filter bed which is being re-sanded4 ,table #i4 ,columns3 ,a - ,july4 ,b - ,august4 ,c - ,september4 ,d - ,october4 ,e - ,november4 ,f - ,december4 ,g - ,january4 ,h - ,february4 ,i - ,march4 ,j - ,april4 ,k - ,may4 ,l - ,june4 7,a7 ,number of ,deaths from ,typhoid ,fever1 by ,months1 in the ,district of ,columbia for the ,last ,fourteen ,fiscal ,years4 ,fiscal year4 ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,total4 ---------------------------------------- ------------------ #ahif-ig #h #ae #be #be #ah #af #ac #d #d #d #f #i #adg #ahig-ih #aj #af #ah #aj #i #ah #h #d #b #i #f #bj #acj #ahih-ii #bd #bb #bb #bh #ba #af #aj #d #g #f #c #f #afi #ahii-aijj #i #ch #cj #bh #bg #bf #ag #f #h #aj #e #ab #aic #aija-jb #af #cc #bh #ba #bb #af #ai #h #ab #i #ac #i #bjf #aijb-jc #ba #ci #be #cb #ai #bj #i #e #i #f #f #c #aid #aijc-jd #ag #bf #ah #ai #h #ad #e #e #f #aj #h #h #add #aijd-je #af #bb #be #ad #aa #i #aa #a #e #g #a #c #abe #aije-jfaae #cj #bc #bf #ad #f #f #d #e #d #aj #i #aeb #aijf-jg #ba #cb #ba #be #ag #d #g #f #d #f #g #b #aeb #aijg-jh #aj #ah #ag #ai #aa #g #d #a #a #h #h #c #ajg #aijh-ji #ae #ac #bc #ag #af #ac #af #h #c #h #g #g #adf #aiji-aj #ab #ab #ag #ab #ab #b #c #d #g #e #e #d #ie ---------------------------------------- ------------------ ,average #ae4cbe4ebb4iba4eaf4fac4ai4fd4de4hf4gf4d g4eaee4d ---------------------------------------- ------------------ ,table #i--7;,continued47 ,columns3 ,a - ,july4 ,b - ,august4 ,c - ,september4 ,d - ,october4 ,e - ,november4 ,f - ,december4 ,g - ,january4 ,h - ,february4 ,i - ,march4 ,j - ,april4 ,k - ,may4 ,l - ,june4 ,m - ,annual death rate4 7,b7 ,number of ,deaths from ,typhoid ,fever ,reduced to ,death ,rates per #ajj1jjj ,inhabitants per ,year4 ,fiscal year4 ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ---------------------------------------- ---------- #ahif-ig #ce #feajiaji #gh #gj #ef #ag #ag #ag #bf #ci #ec #ahig-ih #dc #fi #gh #dc #ci #gh #ca #ag #h #ch #be #he #df #ahih-ii #ajb #ic #icaai #hi #fh #db #ag #bi #be #ab #bf #ei #ahii-aijj #cgaehabeaafaabajh #fi #bd #cc #da #bj #di #gd #aijj-ja #hbafgaahajbaad #fi #bh #h #cb #h #af #dj #fe #aija-jb #fdacbaab #hd #hh #fd #ge #ca #dg #ce #ea #ce #fh #aijb-jc #hcaec #ihabf #ge #gi #ce #ai #ce #bc #bc #ab #fc #aijc-jd #ffajj #fi #gc #ca #ed #ai #ai #bc #ch #cj #cj #df #aijd-je #fa #hc #ie #ec #db #cd #da #d #ai #bf #d #aa #ci #aije-jf #efaaa #he #ig #eb #bb #bb #ae #ah #ae #cf #cc #dg #aijf-jg #fiaje #fi #hb #ef #ac #bd #bj #ac #bj #bd #g #db #aijg-jh #ce #fd #fj #fg #ci #be #ad #d #d #bh #bh #aa #cb #aijh-ji #ec #de #hj #fj #ef #de #ef #bh #aj #bh #bd #bd #dc #aiji-aj #db #db #fj #db #db #g #aa #ad #bd #ag #ag #ad #bh ---------------------------------------- ---------- ,average monthly #ei #ii #hi #hd #fe #ec #ch #bd #bb #bf #bd #cj444 death rate4 ,footnote #a3 ,filtered water supplied since ,october1 #aije4 ,illustration3 ,figure #c--,washington ,aqueduct1 ,d4 ,c41 ,filteration ,plant4 ,sand ,handling1 ,system4 ,illustration3 ,figure #d--,washington ,aqueduct1 ,d4 ,c41 ,filtration ,plant4 ,washer ,sand-,handling1 ,system4 ,illustration3 ,figure #e--,washington ,aqueduct1 ,d4 ,c41 ,filtration ,plant4 ,ejector ,sand-,handling1 ,system4 ,table #aj--,periods of ,operation1 and ,quantities ,filtered4 ,number of ,number of days since previous3 filter runs ---------------------------------------- --- ended after3 ,scraping4 ,raking4 ,month4 ---------------------------------------- ----------- ,scrap- ,rak- ,max4 ,min4 ,ave4 ,max4 ,min4 ,ave4 ing4 ing4 ---------------------------------------- ------------------------ #aiji4 ---------------------------------------- ------------------------ ,july #ad #j #hi #dd #fg4d #j #j #j ,august #h #j #gd #ea #fj4d #j #j #j ,september #ac #j #ih #ec #fh4c #j #j #j ,october #ah #e #ha #cb #ei4i #dc #cc #ci4d ,november #h #b #gi #dd #ec4d #dg #cg #db4j ,december #c #d #fb #fa #fa4c #fc #ej #eg4c ---------------------------------------- ------------------------ #aiaj4 ---------------------------------------- ------------------------ ,january #i #d #ie #gi #hh4j #hh #gb #gg4j ,february #a #d #ii #ii #ii4j #ic #ea #ga4j ,march #c #d #abj #aaj #aac4g #ajh #aja #ajd4c ,april #aj #ab #abf #fb #hd4h #abi #ba #fe4c ,may #c #b #hf #ch #fi4g #ee #cb #dc4e ,june #ac #b #ajj #fa #gi4g #abi #gh #ajc4e ---------------------------------------- ----------------------- ,year #aiji-aj #ajc #ci #abf #cb #ga4a #abi #ba #ff4f ---------------------------------------- ----------------------- ,fiscal years3 ---------------------------------------- ------------------------ #aije-jf #ga #j #aie #ch #ia4a #j #j #j #aijf-jg #aja #d #aii #bd #gg4j #cb #ad #ba4g #aijg-jh #adc #gg #ahj #aa #ed4i #fc #g #bh4f #aijh-ji #abh #ej #ace #aa #di4i #ic #ac #cd4b ,million gallons filtered since previous3 ---------------------------------------- ---------------- ,month4 ,scraping4 ,raking4 ---------------------------------------- ----------- ,max4 ,min4 ,ave4 ,max4 ,min4 ,ave4 ---------------------------------------- ------------------------ #aiji4 ---------------------------------------- ------------------------ ,july #bbi4ja #ajf4bg #afc4bhi #j #j #j ,august #age4ed #abd4id #aeb4eha #j #j #j ,september #bcg4eb #aad4cg #afa4gjb #j #j #j ,october #bjf4ji #gh4gh #acb4cei #if4ej #ga4ea #hb4gjh ,november #afh4ai #hb4cb #aab4fjc #ii4jj #ij4bc #id4fae ,december #ace4gg #abh4cc #acb4fdg #add4ce #ajf4aa #abe4idj ---------------------------------------- ------------------------ #aiaj4 ---------------------------------------- ------------------------ ,january #bjd4ch #adf4eh #agh4dfa #ahi4dh #aeb4cc #agj4gce ,february #bje4gc #bje4gc #bje4gcj #aib4ih #aah4he #aeh4hij ,march #bge4if #beg4cf #bfe4dic #bdi4fh #bbd4di #bch4iic ,april #bie4if #ajd4ac #aha4igb #cjg4eg #de4bb #adb4ddh ,may #ahf4fd #ha4ff #aej4bcj #ajb4ae #fi4gi #he4igh ,june #bac4gj #acj4he #aga4jei #aha4be #afg4hd #agd4edj ---------------------------------------- ------------------------ ,year #aiji-aj #bie4if #ha4ff #aei4aea #cjg4eg #de4bb #adc4hcb ---------------------------------------- ------------------------ ,fiscal years3 ---------------------------------------- ------------------------ #aije-jf #dig4de #aaf4ff #bdj4cgi #j #j #j #aijf-jg #dff4ab #fi4gf #bbj4fic #ajc4bh #cb4ac #gf4hgj #aijg-jh #dgg4ai #bh4bj #adf4iab #afe4be #ag4jh #ge4gge #aijh-ji #bih4jh #ci4bf #abe4fag #bdd4ai #da4da #hh4dci ,in re-sanding a filter1 it is first filled with water to the proposed depth of the sand layer4 ,the outlet end of the hose is connected to a #c-;in4 pipe which is supported on a boat1 and the sand is discharged through this pipe at the point required4 ,work is first begun at the far end of the filter1 and it is gradually filled by swinging the boat from side to side and backing it by degrees to the front end4 ,at first it was feared that a small quantity of mud would be deposited on the surface of the old sand1 and that this mud would ultimately cause subsurface clogging4 ,for this reason1 when this method was first adopted1 a man was required to rake the sand very thoroughly in front of the discharge4 ,later1 it was found that by giving the end of the discharge pipe a slope of about #de degrees downward from the horizontal1 the force of the current of sand and water could be depended on to cut the old surface of sand to any required depth1 and move it ahead together with the new sand1 thus completely breaking up the possible mud layer between the old and new sand layers4 ,after having used this method almost exclusively for #ae months1 in which time eleven filters have been re-sanded1 and #bd1eca cu4 yd4 of sand have been replaced1 there seems to be no indication of an increased initial loss of head4 ,the sand is very compact1 and has no apparent tendency to separate into different sizes4 ,the general appearance is similar to that of very fine sand on the seashore4 ,the filters re-sanded in this way have been considerably more efficient than those in which the sand was replaced with carts1 and as yet1 no harmful results have been noted4 ,the rate at which the sand is replaced is shown in ,table #ab1 and the cost of labor for sand handling is given in detail in ,table #ad1 which shows that quite a perceptible saving has been effected by the hydraulic method4 ,the figures showing the cost for sand handling do not include any charge for the quantity of water used1 that item having been carried on the pumping-station account4 ,table #aa--,quantities of ,sand ,removed4 ,no4 of filters ,cubic yards when last scraped when last treatment was3 treatment was3 ,month4 ---------------------------------------- ------- ,scraping4 ,raking4 ,scraping4,raking4---------------------- ----- ,max4,min4,ave4 ,max4,min4,ave4 ---------------------------------------- ----------------- #aiji4 ---------------------------------------- ----------------- ,july #ad #j #cch #aba #aij4f #j #j #j ,august #h #j #cef #adi #bah4e #j #j #j ,september #h #j #ebd #ig #agh4f #j #j #j ,october #i #e #aej #ic #aae4hcja #aba #afi4j ,november #b #b #acd #hh #aaa4jacb #ha #ajf4e ,december #j #b #j #j #j #acc #abf #abi4e ---------------------------------------- ----------------- #aiaj4 ---------------------------------------- ----------------- ,january #b #d #aee #aab #acc4eaie #aba #adg4h ,february #j #d #j #j #j #cij #afj #bbe4h ,march #a #d #dhi #dhi #dhi4jbfb #agi #bad4c ,april #d #ab #agb #hd #aai4cbcj #adf #agh4h ,may #a #b #cbj #cbj #cbj4jbdi #bda #bde4j ,june #j #b #j #j #j #bjc #aij #aif4e ---------------------------------------- ----------------- ,year #aiji-aj #di #cg #ebd #hd #agf4gcij #ha #aha4j ---------------------------------------- ----------------- ,fiscal ,years3 ---------------------------------------- ----------------- #aije-jf #ga #j #fjj #ga #bej4j #j #j #j #aijf-jg #id #b #ecf #eb #bei4jcih #bgf #ccg4j #aijg-jh #ha #ec #ebg #df #aij4bdaa #ce #aah4d #aijh-ji #ib #ej #ehj #ee #afi4edgb #ha #agg4e ,depth1 in inches1 when last treatment was3 ------------------------------- ,month4 ,scraping4 ,raking4 --------------------------- ,max4,min4,ave4 ,max4,min4,ave4 ---------------------------------------- - #aiji4 ---------------------------------------- - ,july #b4eaj4ija4daej #j #j ,august #b4fea4aaa4fcaj #j #j ,september #c4ijj4gba4ccjj #j #j ,october #a4abj4fij4hfbb4bdj4ija4bef ,november #a4jjj4fej4hbej4ihj4fjj4gij ,december #j #j #j #j4iij4idj4ife ---------------------------------------- - #aiaj4 ---------------------------------------- - ,january #a4aej4hcj4iija4dej4ija4ajj ,february #j #j #j #b4ija4aia4fgh ,march #c4fdc4fdc4fdja4iea4cca4eic ,april #a4bhj4fbj4hhea4gaa4jia4cca ,may #b4chb4chb4chja4hea4gia4hbj ,june #j #j #j #a4eaa4daa4dfj ---------------------------------------- - ,year #aiji-aj #c4ijj4fba4cadb4ijj4fja4cgc ---------------------------------------- - ,fiscal ,years3 ---------------------------------------- - #aije-jf #d4dgj4eca4giij #j #j #aijf-jg #d4jjj4efa4icab4ieb4jeb4ejj #aijg-jh #c4ibj4baa4ejgc4jfj4baj4hha #aijh-ji #d4caj4daa4beic4eaj4fja4cag ,table #ab--,rates of ,sand ,handling4 ,sand removed from filters4 ,sand replaced in filters4 ---------------------------------------- ---------------- ,ejector ,cubic ,average ,ejector ,cubic ,average ,date4 hours4 yards of rate in hours4 yards ofrate in sand cubic yards sand cubic removed per hour removed yards per hour ---------------------------------------- ------------------------- #aijf4 ---------------------------------------- ------------------------- ,april #di #bec #e4b 444 444 444 ,may #chj #b1eaa #f4f 444 444 444 ,june #efg #c1bhj #e4h 444 444 444 ,july #ica #e1cgf #e4h 444 444 444 ,august #aje #ecc #e4a 444 444 444 ,september #cae #a1hib #f4j 444 444 444 ,october #a1jfg #e1agc #e4h 444 444 444 ,november #afh #ice #e4f 444 444 444 ,december #bjc #a1jgc #e4c 444 444 444 ---------------------------------------- ------------------------- #aijg4 ---------------------------------------- ------------------------- ,january #cii #b1igd #g4c 444 444 444 ,february #adj #a1aci #h4a 444 444 444 ,march #aae #hgh #g4f 444 444 444 ,april #dbg #c1ajc #g4c 444 444 444 ,may #acc #ici #g4j 444 444 444 ,june #aje #fgd #f4d 444 444 444 ,july #g #df #f4f 444 444 444 ,august #ij #egd #f4d 444 444 444 ,september #cjf #a1cif #f4e 444 444 444 ,october #bgc #a1gja #f4b 444 444 444 ,november #bjb #a1beh #f4h 444 444 444 ,december #cjd #b1ach #e4i 444 444 444 ---------------------------------------- ------------------------- #aijh4 ---------------------------------------- ------------------------- ,january #edf #c1gjh #f4h 444 444 444 ,february #ih #ggf #g4i 444 444 444 ,march #cae #b1hcb #i4j 444 444 444 ,april #dfi #c1gge #h4a 444 444 444 ,may #ahb #a1dad #g4h 444 444 444 ,june #bhj #b1jeg #g4d 444 444 444 ,july #bhj-a_/b #b1fhc #i4f 444 444 444 ,august #cbg-a_/b #b1hjh #h4f 444 444 444 ,september #djb #c1cga #h4d 444 444 444 ,october #cjh #b1fif #h4g 444 444 444 ,november #dg-a_/b #ccc #g4j 444 444 444 ,december #aec-c_/d #a1bfh #h4c 444 444 444 ---------------------------------------- ------------------------- #aiji4 ---------------------------------------- ------------------------- ,january #aai-a_/b #a1jee #h4h 444 444 444 ,february #afa-a_/b #a1dgi #i4b 444 444 444 ,march #add #a1dfe #aj4b 444 444 444 ,april #bad-c_/d #b1bfj #aj4e #ahh #b1dje #ab4h ,may #bai-c_/d #b1bbc #aj4a #aij #b1aif #aa4e ,june #cee #c1jif #h4g #bdc #c1jed #ab4f ,july #cab-a_/d #b1gjg #h4g #dbe-a_/b #d1jej #i4e ,august #bah-c_/d #a1iee #i4j #fd-a_/b #fbj #i4f ,september #agb-a_/b #a1cfj #g4i #djh #b1hdb #g4j ,october #bjc #a1hgj #i4b #bfa-a_/d #b1cej #i4j ,november #ed #cig #g4d #j #j 444 ,december #fb #chb #f4b #j #j 444 ---------------------------------------- ------------------------- #aiaj4 ---------------------------------------- ------------------------- ,january #ajd #gjc #f4h #j #j 444 ,february #ajf-a_/b #a1jeh #i4i #bh-a_/d #cga #ac4a ,march #ih #ihe #aj4j #gb #a1jjh #ad4j ,april #bfh-c_/d #b1heb #aj4g #acd-a_/d #b1aei #af4a ,may #eh-c_/d #fic #aa4h #aga-c_/d #c1jdb #ag4g ,june #eh-c_/d #fdb #aj4i #i-c_/d #aff #ag4j ,the cost for pumping water for sand handling1 including all labor1 materials1 and repairs1 amounts to #j4jf per cu4 yd4 of sand ejected and washed1 and #j4jc per cu4 yd4 for replacing4 ,in addition to the water used for carrying the sand which is being replaced1 it is customary to keep a slight upward flow in the filter1 thus using about #ejj1jjj gal4 of filtered water per day for this purpose4 ,assuming the value of this water to be the total cost for pumping1 filtering1 etc41 or #c4hj per #a1jjj1jjj gal41 the cost per cubic yard of sand replaced would be about #j4jb when one ejector is used1 and #j4ja when two are in operation4 ,it is not considered absolutely necessary to have an upward flow of water in the filter which is being re-sanded1 and it is not always done4 ,it was used1 however1 as an additional safeguard against the formation of a stratum of mud between the old and new layers of sand while the hydraulic method was in an experimental stage4 ,the quantities of sand removed from the filters per scraping and the rates of sand handling are shown in ,tables #aa and #ab4 ,cost of ,operation4--,it is frequently difficult to compare the relative cost of corresponding items for different plants1 because of the different methods of dividing the cost and the varying opinions of the officials as to what should properly be charged to each item4 ,in order that the data may be in sufficient detail to permit it to be rearranged to compare with other plants1 a list of employees and charges for supplies is given in ,table #ac4 ,this list accounts for the entire appropriation for the care and maintenance of the filtration plant1 including pumping the water to the filters1 parking and caring for the grounds1 buildings1 roads1 sidewalks1 etc4 ,the cost for the various items per million gallons pumped to the filters is shown in ,table #ad1 and the cost per cubic yard of sand handled in ,table #ae4 ,preliminary ,treatment4--,before the present filtration plant was designed1 ,rudolph ,hering1 ,george ,w4 ,fuller1 and ,allen ,hazen1 ,members1 ,am4 ,soc4 ,c4 ,e41 made an investigation and report4 ,this report was dated ,february #ahth1 #aija1 and contained the following paragraph3 ,in consideration of the full evidence1 we recommend the construction of a complete system of slow or sand filters1 with such auxiliary works as may be necessary for preliminary sedimentation1 and the use of a coagulant for part of the time4 ,there is no reason to believe that the use of this coagulant will in any degree affect the wholesomeness of the water4 ,notwithstanding this opinion1 considerable prejudice existed among the citizens of ,washington against the use of a coagulant1 and1 as finally passed1 the bill providing for the construction of the filters did not include an appropriation for the coagulant4 ,table #ac--,list of ,employees1 ,rates of ,pay1 and ,approximate ,cost for ,supplies4 #a ,superintendent #c1jjj4jj #a ,chief ,chemist and ,assistant ,superintendent #b1ajj4jj #a ,first ,assistant ,chemist #a1ejj4jj #a ,second ,assistant ,chemist #a1jjj4jj #a ,stenographer and ,clerk #a1bjj4jj #a ,surveyor #a1bjj4jj #a ,laboratory ,helper #gbj4jj #a ,janitor #fjj4jj #a ,chief ,steam ,engineer #a1hjj4jj #a ,first ,assistant ,steam ,engineer #a1ddj4jj #a ,second ,assistant ,steam ,engineer #a1jhj4jj #c ,oilers1 at #ijj each #b1gjj4jj #c ,firemen1 at #ijj each #b1gjj4jj #c ,laborers1 at #edj each #a1fbj4jj #a ,filter ,foreman #a1bjj4jj #b ,foremen1 at #ijj each #a1hjj4jj #a ,timekeeper #ijj4jj #c ,watchmen and ,gauge ,tenders1 at #ijj each #b1gjj4jj #a ,machinist #a1adj4jj #a ,blacksmith #ijj4jj #a ,storekeeper #ijj4jj #a ,painter #ijj4jj #a ,mechanic #ijj4jj #a ,electrician #ijj4jj #d ,skilled ,laborers at #fjj each #b1djj4jj #a ,watchman and ,special ,officer #ijj4jj #a ,recorder #gbj4jj #bg ,laborers1 at #a4ej per day for #cjj days #ab1aej4jj #c ,teams1 at #b4jj per day for #bjj days #a1bjj4jj ,laboratory and office supplies #b1gjj4jj ,filter supplies1 tools1 hose1 repair of roads1 parks1 shrubs1 etc4 #h1hbj4jj ,pumping station supplies1 oil1 waste1 packing1 repairs1 etc4 #c1egj4jj #c1fjj tons of coal1 at #c4ae per ton #aa1cdj4jj ,charges in ,u4 ,s4 ,engineer ,office1 labor #b1ijj4jj ,charges in ,u4 ,s4 ,engineer ,office1 materials #djj4jj ---------------------------------------- --------------------------- ,total #hb1jjj4jj ,the results obtained from operating the filters being such as to justify the conclusions in the report referred to1 an experimental plant was constructed for the purpose of studying the efficiency of various methods of preliminary treatment of the water4 ,this plant consisted of three cylindrical concrete filter tanks1 each #aj ft4 in diameter4 ,these tanks were filled with the layers of gravel and sand necessary to make them represent as accurately as possible the large slow sand units of the main filtration plant4 ,means were also provided for giving a preliminary treatment to the water supplying each of these experimental slow sand filters4 ,in two cases1 the preliminary treatment was rapid filtration1 while the third consisted of sedimentation and coagulation4 ,the sedimentation tank was of sufficient size1 when compared with the area of the experimental slow sand filter1 to represent the ,georgetown and ,mc,millan ,park ,reservoirs when used in connection with the large filters4 ,the first preliminary filter was very similar in construction and operation to a mechanical filter4 ,the sand for this filter was taken from the main filters1 and1 consequently1 was finer than is generally used in mechanical filters4 ,the second preliminary filter was a ,maignen scrubber4 ,it consisted of a cylindrical concrete tank1 #d ft4 in diameter and #h-a_/b ft4 deep1 which contained #ab in4 of cobble-stones on the bottom1 then1 successively1 #ab in4 of egg-size coke1 #ab in4 of stove-size coke1 #bd in4 of nut-size coke1 and #bd in4 of sponge clippings as the final or top layer4 ,table #ad--;,cost ,per ,million ,gallons ,filtered4 7,a7 ,labor4 ,office ,filter and ,pumping operations3 ,month4 laboratory4 station4 ------------------ ,sand ,repairs handling4 etc4 ---------------------------------------- ----------- #aiji4 ---------------------------------------- ----------- ,july #j4gc #j4eg #j4hf 444 ,august #j4ge #j4fd #j4ei 444 ,september #j4hc #j4fg #j4hj 444 ,october #j4gb #j4ff #j4gc 444 ,november #j4hg #j4gf #j4db 444 ,december #j4ij #j4fi #j4bg 444 ---------------------------------------- ----------- #aiaj4 ---------------------------------------- ----------- ,january #j4ha #j4fc #j4cc 444 ,february #j4id #j4gd #j4ce #j4jg ,march #j4ib #j4ha #j4cj #j4jg ,april #j4ic #j4hc #j4di #j4jc ,may #j4hf #j4gb #j4cf #j4jc ,june #j4hh #j4fg #j4ch 444 ---------------------------------------- ----------- ,average #j4hd #j4gj #j4bg #aj4be ---------------------------------------- ----------- ,fiscal years3 ---------------------------------------- ----------- #aije-aijf #j4de #j4de #j4dg #j4jb #aijf-aijg #j4eg #j4eg #j4eh #j4ba #aijg-aijh #j4gj #j4ef #j4db #j4cb #aijh-aiji #j4gb #j4fa #j4da #j4cd ---------------------------------------- ----------- ,parking ,month4 7care of ,experimental ,main ,total4 grounds74 filters4 ,office4 ---------------------------------------- ----------------- #aiji4 ---------------------------------------- ----------------- ,july #j4ca 444 #j4ae #b4fb ,august #j4ga 444 #j4ad #b4hc ,september #j4ea 444 #j4ag #b4ih ,october #j4cd 444 #j4jh #b4ec ,november #j4ch 444 #j4ah #b4fa ,december #j4dj 444 #j4ab #b4ch ---------------------------------------- ----------------- #aiaj4 ---------------------------------------- ----------------- ,january #j4ad 444 #j4aj #b4ja ,february #j4aa 444 #j4af #b4cg ,march #j4ah 444 #j4ac #b4da ,april #j4cf 444 #j4ac #b4gg ,may #j4ee 444 #j4ah #b4gj ,june #j4ch 444 #j4ab #b4dc ---------------------------------------- ------------------ ,average #j4cf 444 #j4ad #b4ef ---------------------------------------- ------------------ ,fiscal years3 ---------------------------------------- ----------------- #aije-aijf #j4ja 444 #j4ji #a4di #aijf-aijg #j4jg #j4jc #j4jd #b4jg #aijg-aijh #j4ae #j4ji #j4ji #b4cf #aijh-aiji #j4bb #j4ja #j4ac #b4dd ---------------------------------------- ------------------ ,table #ad--7;,continued47 7,b7 ,materials4 ,office ,filter and ,pumping operations3 ,month4 laboratory4 station4 ------------------ ,sand ,repairs handling4 etc4 ---------------------------------------- ----------- #aiji4 ---------------------------------------- ----------- ,july 444 444 #j4ja 444 ,august #j4ja 444 444 444 ,september #j4je #j4ca #j4jd 444 ,october #j4jh #j4aa #j4ac 444 ,november #j4ac #j4gh #j4aj 444 ,december #j4jc #j4ag #j4je 444 ---------------------------------------- ----------- #aiaj4 ---------------------------------------- ----------- ,january #j4ab #j4gd #j4ad 444 ,february #j4jg #a4hh #j4ah 444 ,march #j4bf #j4bh #j4ja 444 ,april #j4ah #a4bb #j4aj 444 ,may #j4jf #j4gb #j4jb 444 ,june #j4ed #b4bc 444 #bb4af ---------------------------------------- ----------- ,average #j4ac #j4fi #j4jb #cj4ba ---------------------------------------- ----------- ,fiscal years3 ---------------------------------------- ----------- #aije-aijf #j4jd #j4ei #j4jb 444 #aijf-aijg #j4jc #j4fg #j4jh #j4bj #aijg-aijh #j4je #j4ed #j4jd #j4jg #aijh-aiji #j4aj #j4fi #j4je #j4ah ---------------------------------------- ----------- ,parking ,month4 7care of ,experimental ,main ,total4 grounds71 filters4 ,office4 ---------------------------------------- ----------------- #aiji4 ---------------------------------------- ----------------- ,july 444 444 444 #j4ja ,august #j4jg 444 #j4ja #j4ji ,september #j4ja 444 #j4jc #j4dd ,october #j4df 444 #j4jb #j4hj ,november #j4cd 444 #j4jb #a4cg ,december #j4ja 444 #j4je #j4ca ---------------------------------------- ----------------- #aiaj4 ---------------------------------------- ----------------- ,january #j4ja 444 444 #a4ja ,february #j4ja 444 #j4ja #b4ae ,march 444 444 444 #j4ee ,april #j4bi 444 #j4jb #a4ha ,may #j4aa 444 #j4jb #j4ih ,june #j4df 444 #j4jd #e4dc ---------------------------------------- ------------------ ,average #j4ag 444 #j4jb #a4bd ---------------------------------------- ------------------ ,fiscal years3 ---------------------------------------- ----------------- #aije-aijf 444 444 444 #j4fe #aijf-aijg #j4jb 444 #a4jj #aijg-aijh #j4jf 444 #j4ja #j4gg #aijh-aiji #j4ah 444 #j4jb #a4bb ---------------------------------------- ------------------ ,footnote #a3 #j4jb for new sand-handling system4 ,footnote #b3 #b4jb for new sand-handling system4 ,footnote #c3 #j4af for new sand-handling system4 ,table #ad--7;,continued47 7,c7 ,totals4 ,office ,filter and ,pumping operations3 ,month4 laboratory4 station4 ------------------- ,sand ,repairs handling4 etc4 ---------------------------------------- ------------ #aiji4 ---------------------------------------- ------------ ,july #j4gc #j4eg #j4hg 444 ,august #j4gf #j4fd #j4ei 444 ,september #j4hh #j4ih #j4hd 444 ,october #j4hj #j4gg #j4hf 444 ,november #a4jj #a4ed #j4eb 444 ,december #j4ic #j4hf #j4cb 444 ---------------------------------------- ------------ #aiaj4 ---------------------------------------- ------------ ,january #j4ic #a4cg #j4dg 444 ,february #a4ja #b4fb #j4ec #j4jg ,march #a4ah #a4ji #j4ca #j4jg ,april #a4aa #b4je #j4ei #j4jc ,may #j4ib #a4dd #j4ch #j4jc ,june #a4db #b4ij #j4ch #b4af ---------------------------------------- ------------ ,average4 #j4ig #a4ci #j4bi #j4df ---------------------------------------- ------------ ,fiscal years3 ---------------------------------------- ------------ #aije-aijf #j4di #a4jd #j4di #j4jb #aijf-aijg #j4fj #a4bd #j4ff #j4da #aijg-aijh #j4ge #a4ac #j4df #j4ci #aijh-aiji #j4hb #a4cj #j4df #j4eb ,parking ,month4 7care of ,experimental ,main ,total4 grounds71 filters4 ,office4 ---------------------------------------- ----------------- #aiji4 ---------------------------------------- ----------------- ,jul #j4ca 444 #j4ae #b4fc ,august #j4gh 444 #j4ae #b4ib ,september #j4eb 444 #j4bj #c4db ,october #j4hj 444 #j4aj #c4cc ,november #j4gb 444 #j4bj #c4ih ,december #j4da 444 #j4ag #b4fi ---------------------------------------- ----------------- #aiaj4 ---------------------------------------- ----------------- ,january #j4ae 444 #j4aj #c4jb ,february #j4ab 444 #j4ag #d4eb ,march #j4ah 444 #j4ac #b4if ,april #j4fe 444 #j4ae #d4eh ,may #j4ff 444 #j4bj #c4fc ,june #j4hd 444 #j4af #g4hf ---------------------------------------- ----------------- ,average4 #j4eh 444 #j4af #c4hj ---------------------------------------- ----------------- ,fiscal years3 ---------------------------------------- ----------------- #aije-aijf #j4ja 444 #j4ji #b4ad #aijf-aijg #j4ji #j4jc #j4jd #c4jg #aijg-aijh #j4ba #j4ji #j4aj #c4ac #aijh-aiji #j4dj #j4ja #j4ae #c4ff ,the two preliminary filters were operated at a rate of about #ej1jjj1jjj gal4 per acre per day1 and the three slow sand filters at rates of from #c1jjj1jjj to #d1jjj1jjj gal4 per day4 ,this plant was put in service during the early part of ,february1 #aijg1 and was kept in practically continuous operation until the end of ,july1 #aijh4 ,illustration3 ,figure #f--,washington ,aqueduct1 ,d4 ,c41 ,experimental ,filters ,below ,dalecarlia ,reservoir ,coagulating ,basins and ,apparatus4 ,table #ae--;,average ,cost for ,labor for ,sand ,handling4 7,a7 ,per ,million ,gallons ,pumped ,to ,filter4 ,month4 ,scrap- ,eject- ,wash- ,smooth-,raking4 ,re- ,total4 ing4 ing4 ing4 ing4 sanding4 ---------------------------------------- ------------------------ #aiji4 ---------------------------------------- ------------------------ ,july #j4aj #j4ba #j4jc #j4jb 444 #j4ba #j4eg ,august #j4jg #j4af #j4jc #j4ja 444 #j4jd #j4ca ,september #j4je #j4ac #j4jb #j4ja #j4ja #j4bg #j4di ,october #j4jf #j4ae #j4jc #j4ja #j4jb #j4ab #j4ci ,november #j4jb #j4jf 444 444 #j4jb 444 #j4gj ,december #j4jb #j4jd #j4ja 444 #j4ja #j4ja #j4ji ---------------------------------------- ------------------------ #aiaj4 ---------------------------------------- ------------------------ ,january #j4jd #j4jg 444 #j4ja #j4jb 444 #j4ad ,february #j4jd #j4aj 444 #j4ja 444 #j4jb #j4ag ,march #j4jd #j4jf 444 #j4ja #j4ja #j4je #j4ag ,april #j4aj #j4ae #j4jd #j4ja #j4jb #j4jf #j4ch ,may #j4jb #j4jc #j4ja 444 #j4ja #j4aa #j4ah ,june #j4jb #j4jd 444 444 #j4jb #j4ja #j4ji ---------------------------------------- ------------------------ ,average #j4je #j4aj #j4ja #j4ja #j4ja #j4jh #j4bf ---------------------------------------- ------------------------ ,fiscal years3 ---------------------------------------- ------------------------ #aije-jf #j4jf #j4bi #j4jb #j4jf 444 #j4jd #j4dg #aijf-jg #j4jg #j4bj #j4je #j4jb 444 #j4bd #j4eh #aijg-jh #j4ji #j4ad #j4jc #j4ja #j4jb #j4ac #j4db #aijh-ji #j4jg #j4ae #j4jc #j4ja #j4ja #j4ad #j4da ---------------------------------------- ------------------------ ,table #ae--7;,continued47 7,b7 ,per ,cubic ,yard of ,sand4 ,month4 ,scrap- ,eject- ,wash- ,smooth-,raking4 ,re- ,total4 ing4 ing4 ing4 ing4 sanding4 ---------------------------------------- ------------------------ #aiji4 ---------------------------------------- ------------------------ ,july #j4jh #j4ae #j4jc #j4ja 444 #j4aj #j4cg ,august #j4jg #j4ae #j4jc #j4ja 444 #j4aa #j4cg ,september #j4jg #j4ag #j4jc #j4ja 444 #j4ag #j4de ,october #j4jf #j4ae #j4jc #j4ja 444 #j4ji #j4cd ,november #j4aj #j4bc #j4jb #j4jb 444 444 #j4cg ,december #j4ab #j4be #j4jd #j4jb 444 #j4jh #j4ea ---------------------------------------- ------------------------ #aiaj4 ---------------------------------------- ------------------------ ,january #j4aj #j4ai 444 #j4jb 444 444 #j4ca ,february #j4jg #j4ae 444 #j4ja 444 #j4ji #j4cb ,march #j4jf #j4aa 444 #j4jb 444 #j4jh #j4bg ,april #j4jg #j4ji #j4jc #j4ja 444 #j4je #j4be ,may #j4jf #j4ji #j4jc #j4ja 444 #j4jf #j4be ,june #j4jf #j4ab 444 #j4ja 444 #j4aj #j4bi ---------------------------------------- ------------------------ ,average #j4jg #j4ad #j4jb #j4ja 444 #j4aj #j4cd ---------------------------------------- ------------------------ ,fiscal years3 ---------------------------------------- ------------------------ #aije-jf #j4jg #j4ce #j4jd #j4jg 444 #j4ad #j4fg #aijf-jg #j4jf #j4ai #j4jc #j4jb 444 #j4ag #j4dg #aijg-jh #j4ji #j4ae #j4jc #j4ja 444 #j4ad #j4db #aijh-ji #j4jf #j4ad #j4jc #j4ja 444 #j4ac #j4cg ,for convenience in referring to the different systems1 the combined rapid and slow sand filter will be designated as ,filter ,plant ,no4 #a1 the combined ,maignen scrubber and slow sand filter as ,filter ,plant ,no4 #b1 and the combined coagulating basin and slow sand basin as ,filter ,plant ,no4 #c4 ,the length of run of ,filter ,plant ,no4 #a was relatively long at first4 ,the rapid rate of filtration1 however1 tended to carry the clay1 which was suspended in the applied water1 to a considerable depth in the filtering material1 so that the runs gradually decreased in length until they were reduced to about three days4 ,unfortunately1 it was necessary to use unfiltered water for washing1 which1 together with the great penetration from the applied water1 finally made it necessary to remove all the filtering materials1 and wash them4 ,although this preliminary filter was operated at a high rate1 its efficiency was quite satisfactory4 ,in fact1 at times when the applied water was comparatively good1 very little work was left for the slow sand filter4 ,at times of high turbidity1 however1 some of the exceedingly fine mud in the applied water passed through this filter1 as well as the slow sand filter connected with it1 and it proved to be absolutely impossible to produce a clear effluent at all times with this combination4 ,filter ,plant ,no4 #b proved more economical and convenient in operation1 but somewhat less efficient than ,filter ,plant ,no4 #a4 ,neither filter could be depended on to give a clear effluent when the applied water was turbid4 ,in the operation of ,filter ,plant ,no4 #c1 sulphate of alumina was used when the applied water contained too much turbidity to be treated satisfactorily by slow sand filters4 ,when the water was comparatively clear1 either one of the three systems1 or slow sand filtration alone1 was entirely satisfactory4 ,at times of high turbidity1 however1 ,filter ,plant ,no4 #c was the only one which could be depended on to produce a clear effluent4 ,a fair comparison between the results of the three systems when treating turbid water in ,january1 #aijh1 is given in ,table #af4 ,table #af shows very clearly that neither ,filter ,plant ,no4 #a nor ,no4 #b would prove at all satisfactory when treating turbid water1 while ,no4 #c could be depended on under all conditions4 ,the results of operation are shown in detail in ,tables #ag1 #ah1 and #ai4 ,it will be noticed in ,table #ag1 that on ,march #ajth1 #aijh1 ,filter ,plant ,no4 #a was put out of service and a ,puech system of preliminary filters was substituted for it4 ,the ,puech preliminary filters consisted of five units containing gravel of varying sizes through which the water was filtered successively before it was finally applied to the final slow sand filter4 ,a general idea of this system may be obtained by referring to ,figure #h4 ,table #af--,turbidity ,results with ,experimental ,filters1 ,during ,period of ,high ,turbidity1 ,january1 #aijh4 ,columns3 ,a - ,effluent preliminary filter4 ,b - ,effluent sand filter4 ,c - ,effluent preliminary filter4 ,d - ,effluent sand filter4 ,e - ,effluent coagulant basin4 ,f - ,effluent sand filter4 ,raw ,filter ,no4 #a4;,filter ,no4 #b4;,filter ,no4 #c4 ,date4 water4---------------------------------- --- ,a ,b ,c ,d ,e ,f ---------------------------------------- --------------- ,january #abth #dj #aj #a #ab #a #b #j ,january #acth #aaj #de #b #ea #b #b #j ,january #adth #baj #ie #c #aac #d #b #j ,january #aeth #cbe #aij #ab #bbb #ae #c #j ,january #afth #cfj #baj #cg #bdg #db #e #j ,january #agth #bdb #abb #bd #adg #bf #f #j ,january #ahth #acg 444 444 #gc #g #f #j ,january #aith #aag #dj #ab clean- 444 #e #j ing ,january #bjth #gb #ca #f sand 444 clean- #j filter ing ,january #bast #ee #bj #d #be #d sand 444 ,january #bb;d #di #ag #c #ba #d filter 444 ,january #bc;d #dj #ab #c #ae #c #c #j ,january #bdth #dj #aa #c #ac #c #c #j ,it is unfortunate that this system was not in operation in ,january1 #aijh1 when the water was cold and turbid4 ,the results1 however1 indicate that it would be no more successful than either ,filter ,plant ,no4 #a or ,no4 #b4 ,experimental ,rate ,studies4--,in ,september1 #aijh1 an experimental plant consisting of six small filters was put in operation4 ,the object of these experiments was to study the relative efficiencies and cost for the operation of slow sand filters when operated at different rates4 ,the units of the plant consisted of cylindrical galvanized-iron tanks #d ft4 in diameter and #i ft4 high4 ,the filter sand in these tanks was taken from the supply for the main filters4 ,it was supported on gravel layers and supplied with under-drains of suitable sizes for the proposed rate of flow in each case4 ,the units of the experimental plant were designated as ,nos4 #a1 #b1 #c1 #d1 #e1 and #f1 and it was the original intention to operate them at rates of #a1jjj1jjj1 #c1jjj1jjj1 #f1jjj1jjj1 #aj1jjj1jjj1 #cj1jjj1jjj1 and #ajj1jjj1jjj gal4 per acre daily1 respectively4 ,this schedule of rates was carried out in a general way with all the filters1 with the exception of ,nos4 #e and #f4 ,for these1 the rates were found to be higher than could be maintained for any great length of time1 owing to the deeper penetration of the mud in the filter sand1 which caused high initial losses of head1 short runs1 and deep scrapings4 ,a rate of about #cj1jjj1jjj gal4 was maintained in the case of ,filter ,no4 #e from the time it was started on ,september #ith1 #aijh1 until ,november #hth1 #aiji1 when it was reduced to about #ag1jjj1jjj gal41 which rate was maintained thereafter until the filter was shut down in ,february1 #aiaj4 ,illustration3 ,figure #g--,plan of ,filter-,house and ,equipment4 ,in the case of ,filter ,no4 #f1 it was found impossible to maintain a rate of #ajj1jjj1jjj gal4 for more than a very few days at a time4 ,it was started at about this rate1 however1 at the beginning of each run1 and kept as high as possible for the remainder of the time during the first seven runs4 ,at the end of the seventh run1 on ,october #agth1 #aijh1 the filter was given a very deep scraping and re-sanded4 ,illustration3 ,figure #h--;,diagrammatic ,sketch ,showing ,arrangements for ,testing ,puech ,system of ,water ,filtration at ,washington ,d4 ,c41 ,u4 ,s4 ,a4 ,the layer of clean sand restored the original capacity1 and the filter was operated as before1 but with gradually decreasing rates until ,december1 #aijh1 when the rate was reduced to about #dj1jjj1jjj gal4 ,even this lower rate was too high to be maintained without removing and replacing a large part of the sand4 ,the rates1 therefore1 gradually decreased to about #bc1jjj1jjj gal4 on ,march #acth1 #aiji1 when the filter was again re-sanded4 ,after this re-sanding the rate was reduced to about #bj1jjj1jjj gal41 and the filter was operated at approximately that rate until it was again re-sanded on ,november #acth1 #aiji1 when the rate was again reduced to about #ad1jjj1jjj gal41 which was maintained until the filter was put out of service on ,february #bhth1 #aiaj4 ,this experimental plant was in service from ,september1 #aijh1 to the latter part of ,february1 #aiaj1 or for about #a-a_/b years1 and the leading results are summarized in ,table #bj4 ,table #ag--,record of ,experimental ,filter ,plant ,no4 #a4 ,columns3 ,a - ,rate1 millions of gallons per acre daily4 ,b - ,loss of head4 ,c - ,rate1 millions of gallons per acre daily4 ,d - ,loss of head4 ,e - ,applied water4 ,f - ,effluent preliminary filter4 ,g - ,effluent final filter4 ,h - ,applied water4 ,i - ,effluent preliminary filter4 ,j - ,effluent final filter4 ,preliminary ,final ,turbidity4 ,bacteria4 ,filter4 ,filter4 ,date4 ---------------------------------------- ------------- ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ---------------------------------------- -------------------- #aijg4 ---------------------------------------- -------------------- ,feb4 #hai4dj #j4ga #c4aj #j4ag 444 444 444 #a1ajj #b1jjjb1ejj ,feb4 #iba4ej #j4ha #c4aa #j4af 444 444 444 #bjj #iej #ejj ,feb4 #ajbj4fj #j4ie #c4jd #j4ad 444 444 444 444 444 444 ,feb4 #aabj4aj #a4jh #c4jc #j4ab #ab #c #b #fjj #ijja1cjj ,feb4 #abai4hj #a4bc #c4jb #j4ac #ad #d #b #fej #fej #fej ,feb4 #acai4ej #a4ch #b4if #j4ab #ae #f #b #fjj #fjj #iej ,feb4 #adba4bj #a4fg #c4ba #j4aa #ae #d #b #fej #gjj #hjj ,feb4 #aebe4dj #b4jc #c4ij #j4ac #ab #d #b #fjj #eej #hjj ,feb4 #afbe4jj #b4bc #c4hi #j4ab #ad #c #b #hej #eej #ejj ,feb4 #ag ,shut down for changes in size of meter and piping4 ,feb4 #ah 444 444 444 444 444 444 444 #a1bjj 444 #fej ,feb4 #bach4fj #a4ei #c4ic #j4ah #bj #d #b #a1hjj #a1ajj #gjj ,feb4 #bbch4jj #a4hd #c4ib #j4ae #ae #c #b ,holiday4 ,feb4 #bcdb4aj #b4cf #c4ie #j4ad #bj #e #b #a1fjj #fjj #bbj ,feb4 #bddg4ij #c4jd #c4ic #j4ac #bj #f #c ,sunday4 ,feb4 #be ,shut down change meter #a1djj #hjj #dej from outlet to inlet4 ,feb4 #bg 444 #b4bd 444 #j4ac #ag #f #c #gjj #eej #bhj ,feb4 #bhdi4hj #b4ee #c4ij #j4ac #ae #f #c #hjj #dgj #bcj ---------------------------------------- -------------------- ,mar4 #aej4jj #b4ij #c4ic #j4ac #ae #e #c #fej #dej #adj ,mar4 #bej4bj #c4ba #c4ic #j4ac #ae #e #c #a1jjj #fej #bjj ,mar4 #cch4hj #c4ji #c4hi #j4ac #ca #h #c ,sunday4 ,mar4 #dej4jj #c4ed #c4ic #j4ab #ce #aj #e #a1bjj 444 444 ,mar4 #eej4jj #d4ja #c4ij #j4ac #ace #ci #h #ac1jjj #c1gjj #fjj ,mar4 #fej4jj #d4hb #c4ij #j4ac #ace #ci #h #ah1jjj #d1ejj 444 ,mar4 #gej4jj #e4hi #c4ij #j4ac #ajb #cd #f #bd1jjj #e1jjjb1jjj ,mar4 #hej4jj #f4eh #c4ij #j4ac #ajj #be #d #bb1jjj #e1jjja1djj ,mar4 #iej4jj #g4ba #c4ic #j4ac #ij #be #d #bd1jjj #d1jjj #fej ,mar4 #ajej4jj #g4eb #c4ij #j4ac #hb #bb #e ,sunday4 ,washed4 ,mar4 #aaej4jj #j4hd #c4ij #j4ac #fh #ai #f #ah1jjj #b1ajj #cej ,mar4 #abej4jj #j4ie #c4if #j4ac #df #ai #d #aa1jjj #f1jjj #caj ,mar4 #acej4jj #a4ag #c4ii #j4ac #dj #ai #d #i1jjj #d1ijj #cjj ,mar4 #adej4jj #a4ec #d4ja #j4ac #ci #ag #d #e1ejj #a1cjj #acj ,mar4 #aeej4jj #b4bg #d4je #j4ac #ce #ae #d #f1ejj #a1ejj #fj ,mar4 #afej4jj #c4jh #d4jc #j4ac #fj #bj #d #e1jjj #a1bjj #ajj ,mar4 #agej4jj #d4bf #d4jc #j4ac #ace #ce #d ,sunday4 ,mar4 #ahej4jj #e4fe #d4jj #j4ac #agj #di #g #i1jjj #a1bjj #ie ,mar4 #aiej4jj #g4jb #d4ja #j4ac #abe #cg #f #g1jjj #fjj #ajj ,washed4 ,mar4 #bjej4jj #a4jh #c4ih #j4ac #ajb #cj #e #d1hjj #cjj #ge ,mar4 #baej4jj #a4bc #c4ih #j4ab #abe #cb #d #h1ejj #a1jjj #he ,mar4 #bbej4jj #a4df #d4jj #j4ac #aij #fe #d #g1ejj #a1ajj #de ,mar4 #bcej4jj #a4gf #c4ii #j4ac #ahj #fe #f #g1ejj #fjj #ee ,mar4 #bdej4jj #b4aa #c4ii #j4ab #adj #eb #g ,sunday4 ,mar4 #beej4jj #b4df #d4jj #j4aa #hh #cj #e #d1djj #ejj #he ,mar4 #bfej4jj #b4ge #d4jj #j4ab #fb #bb #d #c1fjj #cjj #fe ,mar4 #bgej4jj #c4jd #d4jh #j4ac #dg #ah #d #b1bjj #afj #fj ,mar4 #bhej4jj #c4ch #c4id #j4aa #ce #aj #c #a1cjj #ajj #ee ,mar4 #biej4jj #c4gj #d4jj #j4aa #bf #h #c #gjj #hj #bi ,mar4 #cjej4jj #d4db #d4jj #j4aa #be #f #c #caj #gj #ce ,mar4 #caej4jj #e4be #c4ii #j4aa #ba #e #b ,sunday4 ---------------------------------------- -------------------- ,apr4 #aej4jj #f4ad #d4jj #j4ab #bj #e #b #fjj #be #cj ,washed4 ,apr4 #bej4jj #b4aj #d4jj #j4ab #bd #e #b #bgj #bh #cb ,apr4 #cej4jj #c4jj #d4jj #j4ab #bd #e #b #dfj #bf #dc ,apr4 #dej4jj #d4ja #d4jj #j4ab #bj #e #b #bhj #bj #bf ,apr4 #eej4jj #e4ae #d4jj #j4ab #bj #d #b #dej #cg #da ,washed4 ,apr4 #fej4jj ,o4#gf #c4ei #j4ab #bj #d #b #cbj #f #cd ,apr4 #gej4jj ,o4#ii #c4dg #j4ab #bj #d #b ,sunday4 ,apr4 #hej4jj #a4ci #d4jc #j4ad #ah #c #b #ccj #aj #bj ,apr4 #iej4jj #b4jd #d4ja #j4ac #ah #c #b #adj #i #ce ,apr4 #ajej4jj #c4jc #d4jb #j4ac #cj #b #a #gej #dc #bi ,apr4 #aaej4jj #d4de #d4jb #j4ad #ff #a #a #d1jjj #ijj #bf ,apr4 #abej4jj #f4ad #d4ja #j4ac #gb #aa #b #ad1jjj #a #gjj #da ,washed4 ,apr4 #acej4jj #j4ie #d4jj #j4ad #hj #ba #b #ac1jjj #a #cjj #gj ,apr4 #adej4jj #a4ah #d4jj #j4ac #gg #be #c ,sunday4 ,apr4 #aeej4jj #a4eg #d4jj #j4ad #fb #ba #c #g1jjj #chj #ee ,apr4 #afej4jj #b4cc #d4jj #j4ae #dg #bj #c #c1fjj #afj #cc ,apr4 #agej4jj #c4cc #d4jj #j4ae #ci #ae #b #a1fjj #gj #ci ,apr4 #ahej4jj #d4ha #d4jj #j4af #cj #aj #b #a1haj #acj #cd ,apr4 #aiej4jj #f4bi #c4ii #j4af #be #g #b #gij #ej #cb ,washed4 ,apr4 #bjej4jj #j4ic #d4ja #j4af #bj #e #b #edj #bd #bh ,apr4 #baej4jj #a4cf #c4ig #j4af #bj #c #b ,sunday4 ,apr4 #bbej4jj #b4bb #d4jb #j4af #ah #b #a #bce #ae #bh ,apr4 #bcej4jj #c4cc #c4ii #j4ad #ae #b #a #agj #ad #af ,apr4 #bdej4jj #d4gh #c4ig #j4ae #ai #a #a #aej #cb #ad ,apr4 #beej4jj #f4dc #c4ij #j4ae #cd #a #a #gjj #bj #ah ,washed4 ,apr4 #bfej4jj ,o4#ig #c4ig #j4ad #df #b #a #a1bjj #af #af ,apr4 #bgej4jj #b4cg #d4jj #j4ad #eb #c #a #a1gjj #be #ag ,apr4 #bhej4jj #e4cc #c4ii #j4ad #de #d #a ,sunday4 ,washed4 ,apr4 #biej4jj #j4ha #c4ii #j4ad #dd #e #a #fjj #af #ag ,apr4 #cjej4jj #a4ge #c4ii #j4ad #ci #f #a #eej #bg #ab ---------------------------------------- -------------------- ,may #aej4jj #j4hj #c4ii #j4ad #ca #e #a #ejj #bd #aa ,washed4 ,may #bej4jj #a4ac #d4jj #j4ad #bd #d #a #ejj #ab #af ,may #cej4jj #b4ji #d4jj #j4ad #ai #c #a #bhj #cj #be ,may #dej4jj #c4hj #d4jj #j4ad #af #b #a #djj #bj #ab ,may #eej4jj #e4ch #d4jj #j4ad #ae #a #a ,sunday4 ,washed4 ,may #fej4jj #j4ia #c4ij #j4ad #ac #a #a #cij #ej #dj ,may #gej4jj #a4ef #c4ij #j4ad #ab #a #a #aij #ai #hj ,may #hej4jj #b4be #c4ii #j4ad #aj #a #a 444 444 444 ,may #iej4jj #c4cg #d4jj #j4ad #aj #a #a #cij #ba #ch ,may #ajej4jj #e4af #d4jj #j4ad #aj #a #a #cjj #ad #ac ,washed4 ,may #aaej4jj #a4jc #d4jj #j4ad #ab #a #a #cij #ac #ab ,may #abej4jj #a4hi #d4jj #j4ad #ag #a #a ,sunday4 ,may #acej4jj #c4hb #d4jj #j4ad #ce #b #a #fjj #cc #ae ,may #adej4jj #f4ca #d4jj #j4ad #ci #c #a #ejj #bg #g ,washed4 ,may #aeej4jj #j4he #d4jj #j4ad #ag #b #a #ejj #bj #bi ,may #afej4jj #a4db #c4ii #j4ad #bd #b #a #bij #ai #dj ,may #agej4jj #b4dg #c4ii #j4ad #ah #b #a #bfj #ai #af ,may #ahej4jj #d4ca #d4jj #j4ac #ae #a #a #aij #af #bj ,washed4 ,may #aiej4jj #j4hc #c4ii #j4ac #ab #a #a ,sunday4 ,may #bjej4jj #a4ff #d4jj #j4ac #ab #a #a #bfj #ag #da ,may #baej4jj #c4hc #d4jj #j4ac #af #a #a #bfj #bf #be ,washed4 ,may #bbej4jj #j4hb #c4ii #j4ac #bj #a #a #bhj #af #ai ,may #bcej4jj #a4fd #d4jj #j4ac #ae #a #a #acj #bj #bb ,may #bdej4jj #c4he #d4jj #j4ac #ae #a #a #agj #ag #cb ,washed4 ,may #beej4jj #j4hd #d4jj #j4ac #ae #a #a #cdj #be #ee ,may #bfej4jj #a4fg #c4ii #j4ac #ah #a #a ,sunday4 ,may #bgej4jj #c4jc #d4jj #j4ac #ac #a #a #baj #aj #dj ,washed4 ,may #bhej4jj #j4hg #d4ja #j4ac #af #a #a #bfj #bf #ee ,may #biej4jj #a4dc #d4ja #j4ac #af #a #a #ejj #ai #ej ,may #cjej4jj #b4ee #d4jj #j4ac #ad #a #a ,holiday4 ,may #caej4jj #d4ai #d4jj #j4ac #ag #a #a #chj #bb #ej ---------------------------------------- -------------------- ,june #aej4jj #f4bf #c4ii #j4ac #ae #a #a #ijj #bg #ej ,washed4 ,june #bej4jj #j4gh #c4ih #j4ac #ag #a #a ,sunday4 ,june #cej4jj #a4ai #d4jj #j4ac #bd #a #a #eej #da #ej ,june #dej4jj #b4ae #d4jj #j4ac #cg #b #a #f1ejj #aej #fj ,june #eej4jj #c4fg #d4ja #j4ac #fe #d #a #c1bjj #aej #df ,june #fej4jj #f4jf #d4jj #j4ad #gg #ab #a #a1ejj #fj #bg ,washed4 ,june #gej4jj #j4hf #d4jj #j4ad #fd #ai #a #b1ajj #fh #de ,june #hej4jj #a4da #d4jj #j4ad #df #af #a #fjj #ce #dd ,june #iej4jj #b4fb #d4ja #j4ad #dd #ab #a ,sunday4 ,june #ajej4jj #d4gi #d4jj #j4ad #cf #h #a #bdj #ca #ce ,washed4 ,june #aaej4jj #j4gg #d4jj #j4ad #cj #f #a #bhj #dg #dg ,june #abej4jj #a4bj #d4ja #j4ad #cd #f #a #ccj #gj #ee ,june #acej4jj #b4db #d4jj #j4ad #ce #h #a #dhj #dc #ge ,june #adej4jj #d4dd #d4jj #j4ae #ca #g #a #ddj #ee #de ,washed4 ,june #aeej4jj #j4hj #c4ii #j4ae #cb #f #a #dbj #ag #cd ,june #afej4jj #a4ae #d4jj #j4ae #bf #e #a ,sunday4 ,june #agej4jj #b4ae #c4ii #j4ad #bf #e #a #cdj #ee #cg ,june #ahej4jj #d4cf #d4jj #j4ad #ca #f #a #ddj #ad #adj ,washed4 ,june #aiej4jj #j4gi #d4ja #j4ae #cg #h #a #ejj #gj #bd ,june #bjej4jj #a4ai #d4jj #j4ae #cj #g #a #ccj #di #bg ,june #baej4jj #b4fe #c4ih #j4ad #be #e #a #agj #cj #ah ,june #bbej4jj #e4eh #d4jj #j4ad #bj #d #a #ajj #ah #ac ,washed4 ,june #bcej4jj #j4he #c4fb #j4ac #bf #c #a ,sunday4 ,june #bdej4jj #b4jb #c4ii #j4ac #adj #aa #a #a1gjj #bg #cf ,june #beej4jj #d4gg #c4ii #j4ac #acj #bf #a #djj #gj #bc ,washed4 ,june #bfej4jj #j4gc #d4ja #j4ac #hb #bg #a #gej #bjj #da ,june #bgej4jj #a4ag #d4ja #j4ac #fe #ah #a 444 444 444 ,june #bhej4jj #c4aj #c4ii #j4ac #dg #af #a 444 #bj 444 ,washed4 ,june #biej4jj #j4fg #c4ii #j4ac #cg #g #a #bbj #ce #bi ,june #cjej4jj #a4jb #d4jj #j4ac #cj #f #a ,sunday4 ---------------------------------------- -------------------- ,july #aej4jj #b4gj #c4ii #j4ac #cj #f #a #djj #df #c ,washed4 ,july #bej4jj #j4fi #d4jj #j4ac #cb #g #a #ahj #hj #ch ,july #cej4jj #a4ba #c4ii #j4ac #cf #h #a #cej #gj #ij ,july #dej4jj #c4dj #c4ii #j4ac #dd #aj #a ,holiday4 ,washed4 ,july #eej4jj #j4gg #c4ii #j4ac #dd #aa #a #eej #ahj #cd ,july #fej4jj #a4ai #d4ja #j4ac #ci #aj #a #bej #fj #bf ,july #gej4jj #c4gb #c4ii #j4ac #cd #h #a ,sunday4 ,washed4 ,july #hej4jj #j4gh #c4ig #j4ac #be #e #a #bbj #ca #ba ,july #iej4jj #a4bg #c4ih #j4ac #bb #d #a #ej #aj #i ,july #ajej4jj #c4aa #d4ji #j4ac #dg #i #a ,lost4 ,washed4 ,july #aaej4jj #j4hc #c4ii #j4ac #ij #ai #a #aej #ai #h ,july #abej4jj #a4dg #c4ii #j4ac #ig #be #a #cjj #dj #bc ,july #acej4jj #c4fa #d4jj #j4ac #if #bi #a #bbj #dg #af ,washed4 ,july #adej4jj #j4hd #c4ii #j4ac #ij #cj #a ,sunday4 ,july #aeej4jj #a4cj #d4jj #j4ac #ie #cj #a #cge #ee #ba ,july #afej4jj #b4gb #c4ii #j4ad #abj #ce #a ,lost4 #ij #ac ,july #agej4jj #e4jh #c4ii #j4ad #he #cb #a #bgj #b #aa ,washed4 ,july #ahej4jj #j4he #c4ii #j4ad #ef #bb #a #a1fge #gj #ej ,july #aiej4jj #a4dc #d4jj #j4ad #da #ab #a #dej #ie #bb ,july #bjej4jj #c4bc #c4ii #j4ad #fb #ai #a #cjj #ch #aa ,washed4 ,july #baej4jj #j4hj #c4ii #j4ad #fb #ba #a ,sunday4 ,july #bbej4jj #a4jf #c4ih #j4ad #hj #bf #a #a1djj #aej #g ,july #bcej4jj #b4ah #c4ii #j4ad #aje #cj #a #c1gjj ,lost4 #aa ,july #bdej4jj #d4ie #c4ih #j4ae #ie #cj #a #ggj ,lost4 #bb ,washed4 ,july #beej4jj #j4hd #c4ih #j4ae #gg #bb #a #bej #cc #aa ,july #bfej4jj #a4bb #c4ih #j4ae #fg #ai #a #adj #ajj #d ,july #bgej4jj #b4cf #d4jj #j4af #ed #ae #a #cjj #ie #g ,july #bhej4jj #d4gd #c4ih #j4af #df #ab #a ,sunday4 ,washed4 ,july #biej4jj #j4hc #c4ii #j4ag #cf #aj #a #dgj #aaj #ah ,july #cjej4jj #a4jb #d4jj #j4ag #bi #g #a ,plates lost4 ,july #caej4jj #a4ff #d4jj #j4ag #ba #e #a ,plates lost4 ---------------------------------------- -------------------- ,aug4 #adh4bj #b4ie #d4jj #j4ag #af #d #a ,plates lost4 ,aug4 #bdf4dj #d4if #d4jj #j4ag #ae #b #a #acj #db #ac ,washed4 ,aug4 #cdb4fj #j4gi #d4jj #j4ag #af #a #a #abj #d #af ,aug4 #ddi4aj #j4ia #d4jj #j4ag #ba #a #a ,sunday4 ,aug4 #edi4aj #a4ei #d4jj #j4ag #bi #a #a #bcj #afj #aa ,aug4 #fdh4bj #c4af #d4jj #j4ag #cd #b #a #he #bjj #ab ,aug4 #gde4fj #e4fe #c4ii #j4ag #ba #b #a #bjj ,lost #d ,washed4 ,aug4 #hej4jj #j4hj #c4ii #j4ag #ai #b #a #ajj #gj #aa ,aug4 #idi4aj #j4id #d4jj #j4ag #af #a #a #ge #dd #i ,aug4 #ajdh4bj #a4ea #d4jj #j4ag #bd #a #a #fj #ac #f ,aug4 #aadh4bj #c4cb #d4jj #j4ag #fb #c #a ,sunday4 ,washed4 ,aug4 #abda4ij #j4hc #c4ii #j4ag #abj #ad #a #fbj #aaj #e ,aug4 #acdi4aj #a4ad #c4ii #j4ag #ajg #bi #a #hbj #ec #cf ,aug4 #addi4aj #a4gb #d4jj #j4ah #hb #cj #a #hej #afj #aaj ,aug4 #aedh4bj #c4cj #d4jj #j4ah #fe #bb #a #aej #cg #d ,aug4 #afdf4dj #j4hd #d4jj #j4ai #de #ae #a #bgj #aaj #ac ,aug4 #agdh4bj #a4je #d4jj #j4ai #ce #aj #a #cdj #aaj #f ,aug4 #ahej4jj #a4ed #d4jj #j4ai #ba #e #a ,sunday4 ,aug4 #aidi4aj #b4bi #d4jj #j4ai #ah #d #a #ahj #he #ac ,aug4 #bjdi4aj #c4gd #c4ii #j4ai #bj #b #a #baj #he #h ,washed4 ,aug4 #badd4aj #a4ja #c4ih #j4ai #bj #b #a #acjj #aae #i ,aug4 #bbde4fj #a4hf #d4jj #j4ai #bg #b #a #chjj #bfe #a ,aug4 #bcdg4cj #d4jh #c4ii #j4ai #di #b #a #bejj #gj #ac ,washed4 ,aug4 #bdda4cj #a4bi #c4ig #j4ai #cf #f #a #cijj #df #f ,aug4 #bedd4aj #b4aa #c4ih #j4bj #cd #g #a ,sunday4 ,aug4 #bfdh4bj #c4db #c4ii #j4bj #ba #e #a #gjj #adj #j ,aug4 #bgdh4bj #e4aj #d4jj #j4bj #ai #d #a #dgj #ajj #d ,washed4 ,aug4 #bhdf4dj #a4bh #d4jj #j4bj #ah #c #a #ejj #di #c ,aug4 #bida4ij #a4ij #d4jb #j4bj #ag #b #a #cfj #hj #j ,aug4 #cjde4fj #c4bc #d4jj #j4bj #ae #a #a #cbj #aij #a ,aug4 #cadf4dj #d4eg #d4jj #j4bj #ac #a #a #bjj #bj #c ---------------------------------------- -------------------- ,sept4 #aej4jj #e4ag #c4fe #j4bj #ad #a #a ,sunday4 ,sept4 #bdh4bj #e4ig #d4jj #j4bj #ab #a #a ,holiday4 ,washed4 ,sept4 #cdg4cj #a4ac #d4jj #j4bj #ab #a #a #cjj #i #a ,sept4 #ddh4bj #b4ja #d4jj #j4bj #af #a #a #fjj #fj #b ,sept4 #edf4dj #e4da #c4fg #j4bj #cd #a #j #cfj #gb 444 ,washed4 ,sept4 #fdj4fj #a4db #c4ih #j4bj #afj #ab #j #aejjj #adj #j ,sept4 #gdb4fj #e4ai #c4ii #j4bj #fd #ah #a #bjjj #acj #a ,washed4 ,sept4 #hdb4fj #a4be #d4jj #j4bj #ef #ah #a ,sunday4 ,sept4 #idf4dj #c4jg #d4jj #j4bb #ei #ah #a #bbj #hj #d ,washed4 ,sept4#ajde4fj #a4jb #c4ii #j4bc #eg #af #a #ahjjj #eg #h ,sept4#aadh4bj #b4cf #d4jj #j4bc #fe #ah #a #bgjj #ij #a ,washed4 ,sept4#abdd4aj #a4ad #c4ii #j4bd #gb #ah #a #ajjj #dg #d ,sept4#acdf4dj #c4fa #c4ii #j4be #hg #bj #a #bcjj #gg #e ,washed4 ,sept4#adch4bj #a4db #c4ig #j4bf #gb #ai #a #bdjj #hj #e ,sept4#aede4fj #d4bg #d4jj #j4bg #fe #ah #a ,sunday4 ,washed4 ,sept4#afdj4jj #a4jf #c4ii #j4bh #fe #ah #a ,lost4 #bb,lost4 ,sept4#agdf4dj #b4dh #d4ja #j4bh #eb #af #a #dbj #ge #a ,washed4 ,sept4#ahdf4dj #a4aa #d4jj #j4bh #fj #ac #a #ijj #cg #c ,sept4#aidf4dj #b4gf #d4jj #j4bh #he #af #a #bjjj #ahf #j ,washed4 ,sept4#bjdd4aj #a4ab #d4jj #j4ca #ajj #ai #a #dbjj #aaj #g ,sept4#badh4bj #b4jg #c4ii #j4cc #abj #bd #a #aajj #aaj #c ,washed4 ,sept4#bbdd4aj #a4cj #c4fg #j4cd #acg #bi #a ,sunday4 ,sept4#bcde4fj #c4gi #c4ii #j4ci #aab #be #a #bdjj #ej #b ,washed4 ,sept4#bdde4fj #a4ae #c4ig #j4dj #ajj #be #a #djjj #fi #d ,sept4#bedh4bj #b4jf #d4jj #j4db #dcb #ec #a #efjjj #fhj #j ,sept4#bf ,stopped1 unable to wash preliminary4 ,sept4#bhej4jj #a4gd #d4jj #j4ga #abg #ce #a 444 444 #cg ,washed4 ,sept4#bidd4aj #b4he #c4ii #j4hb #aje #ca #a ,sunday4 ,sept4#cjdd4ij #c4gh #c4ig #a4jd #aae #cb #a ,lost4 ,lost4 #afj ,washed4 ---------------------------------------- -------------------- ,oct4 #add4aj #a4bj #c4ih #a4cd #hb #bf #a #fjj #ahj #ee ,oct4 #bdi4aj #c4bb #c4ig #a4ed #fe #ai #a #d1djj #abj #e ,washed4 ,oct4 #cdd4aj #a4ca #c4ig #a4ef #ei #ag #a #ijj #ee #aj ,oct4 #ddi4aj #b4ig #c4ig #a4fe #ee #ae #a #hej #fj #f ,washed4 ,oct4 #edd4ij #a4ca #c4ih #a4ge #ei #af #a #b1jjj #aaj #ch ,oct4 #fdf4dj #c4fe #c4ii #a4hi #ei #ag #a ,sunday4 ,washed4 ,oct4 #gdd4ij #a4cd #c4ih #a4ii #eb #ac #a #a1bej #gj #ae ,oct4 #hdi4aj #c4di #c4ih #b4ag #ed #ac #a #aa1jjj #fe #f ,washed4 ,oct4 #idd4aj #a4bj #c4ig #b4cc #ea #ac #a #b1jjj #he #d ,oct4 #ajdi4aj #b4bb #c4ih #b4ee #ej #ab #a #hjj #cf #aj ,oct4 #aadf4dj #d4ei #d4jj #b4ea #dg #aa #a #b1jjj #eg #aj ,oct4 #ab ,shut off to remove sand in preliminary filter in order to clean out the under-drains4 ---------------------------------------- -------------------- ,nov4 #eej4jj #a4ch #c4ig #c4di #ahe #ej #a 444 444 444 ,nov4 #fdh4bj #c4be #c4ih #c4gi #agj #eb #a #e1jjj #a1ejj #bdj ,washed4 ,nov4 #gde4fj #a4ah #c4ih #d4je #ajj #ce #a #ad1jjj #a1jjj #bbj ,nov4 #hdh4bj #d4jh #c4ii #d4cg #ie #cb #a #a1ijj #bgj #afj ,nov4 #idb4jj #f4eh #c4ih #d4ci #hj #bg #a #d1jjj #ejj #aij ,nov4 #aj ,shut down for scraping4 ,removed #bff1jjj cu4 cm4 of sand4 ,nov4 #abej4jj #j4ih #c4ii #j4be #dj #aj #a 444 444 444 ,nov4 #acej4jj #a4ea #d4jj #j4bb #cf #h #a #a1fjj #gej #he ,nov4 #addh4bj #b4fj #d4jj #j4ba #db #aa #a #b1gjj #gjj #baj ,nov4 #aedg4cj #c4hj #d4jj #j4bj #ce #i #a #a1hjj #cej #ahj ,nov4 #afdg4cj #d4hg #d4jj #j4ai #bf #e #a #a1ajj #bjj #cd ,nov4 #agej4jj #e4ge #d4jj #j4ai #bj #d #a ,sunday4 ,nov4 #ahej4jj #f4da #d4jj #j4ai #ag #c #a #a1fjj #bij #ee ,washed4 ,nov4 #aidh4bj #a4jf #c4ii #j4bj #af #b #a #a1cjj #dhj #fj ,nov4 #bjdh4bj #b4je #c4ii #j4bj #de #c #a #f1ejj #c1gjj #hjj ,nov4 #badh4bj #c4dh #c4ii #j4bj #eb #i #a #i1ijj #d1jjj #cjj ,nov4 #bbdg4cj #d4he #c4ii #j4bj #fe #ag #a #aj1jjj #a1jjj #chj ,nov4 #bcdh4bj #f4aa #c4ii #j4bj #di #ae #a #ah1jjj #a1jjj #cbj ,washed4 ,nov4 #bddf4dj #c4ga #c4ih #j4bj #acd #bd #a ,sunday4 ,nov4 #be ,shut down for fear of washing preliminary with such muddy water4 ,nov4 #biej4jj #a4ee #d4jj #j4ba #hj #be #a 444 444 444 ,nov4 #cjdg4cj #c4ad #c4ih #j4bb #ed #af #a #c1hjj #iej #afj ---------------------------------------- -------------------- ,dec4 #adg4cj #d4dh #c4ih #j4bc #cg #aj #a ,sunday4 ,dec4 #bdg4cj #e4fc #c4ih #j4be #cf #f #a #b1ijj #eej #ij ,washed4 ,dec4 #cdf4dj #j4ih #c4ii #j4be #bi #f #a #b1ijj #dhj #ge ,dec4 #dej4jj #a4ae #c4ii #j4bf #bj #d #a #b1jjj #bgj #gj ,dec4 #eej4jj #a4dh #d4jj #j4be #ah #c #a #a1ajj #bgj #ej ,dec4 #fdh4bj #b4jd #c4fc #j4be #af #b #a #c1jjj 444 444 ,dec4 #gdh4bj #b4hj #d4jj #j4bf #ad #a #a #b1djj #aij #aj ,dec4 #hej4jj #c4dj #c4gb #j4bg #ab #a #a ,sunday4 ,dec4 #idi4aj #c4ic #d4jj #j4bg #aa #a #a #a1bjj #agj #g ,dec4 #ajdi4aj #d4ej #d4jj #j4bg #ab #a #a #hjj #ij #ee ,dec4 #aadh4bj #e4eb #d4jj #j4bg #bee #dd #a #f1ejj --- --- ,dec4 #ab ,shut down #ab_/aa at #f ,p4 ,m4 turbidity too high to wash4 ,dec4 #ae --- --- --- --- --- --- --- ,sunday4 ,dec4 #afej4jj #d4jb #c4ii #j4bh #ij #ce #b --- --- --- ,washed4 ,dec4 #agdj4jj #a4ij #c4ig #j4cj #gj #be #b #ba1jjjaj1jjja1bjj ,washed4 ,dec4 #ahdd4aj #a4jh #c4ig #j4ca #di #ae #b #f1ejj #d1bjj #hjj ,dec4 #aidh4bj #a4hh #c4ih #j4ca #ci #aj #a ,lost4 ,lost4,lost4 ,dec4 #bjdf4dj #d4gg #c4ii #j4ca #db #ac #a ,dec4 #badf4dj #f4fh #c4ii #j4cb #bf #f #a ,washed4 ,dec4 #bbdi4aj #a4ad #c4ii #j4cb #bj #d #a ,sunday4 ,dec4 #bcdi4aj #b4ag #d4jj #j4ca #cd #g #a #a1djj #cjj #ajj ,dec4 #bddi4aj #c4gf #d4jj #j4ca #aie #ef #a #i1jjj #iej #gj ,dec4 #be,shut down #ab_/bd at #i ,p4,m4 turbidity too high to wash4 ,holiday ,dec4 #cjej4jj #b4fa #c4ig #j4cc #ef #ai #b --- --- --- ,dec4 #cadd4hj #e4eg #c4ih #j4cf #ci #ab #a --- --- --- ,washed4 ---------------------------------------- -------------------- #aijh4 ---------------------------------------- -------------------- ,jan4 #adf4dj #a4cj #c4ih #j4cf #ca #f #a ,holiday4 ,jan4 #bdh4bj #c4cf #d4jj #j4cf #ci #i #a --- --- --- ,jan4 #cdg4cj #d4ie #c4ii #j4ce #cf #i #a #c1ajj #dij #ij ,jan4 #dej4jj #e4bh #c4ii #j4ce #cb #g #a #b1djj #bdj #dc ,jan4 #edi4aj #f4bf #d4jj #j4ce #bf #e #a ,sunday4 ,washed4 ,jan4 #fdi4aj #j4ii #c4ih #j4ce #bj #d #a #fjj #bjj #cg ,jan4 #gej4jj #a4ae #d4jj #j4ce #bj #d #a #a1ajj #aej #dg ,jan4 #hej4jj #a4da #d4jj #j4ce #bb #d #a #a1ijj #afj #cj ,jan4 #idi4aj #a4ib #d4jj #j4ce #de #aa #a #ac1jjj #a1cjj #gj ,jan4 #ajdi4aj #b4ef #d4jj #j4cf #gj #be #a #aj1jjj #c1ejj #agj ,jan4 #aaej4jj #c4ag #c4ii #j4cg #ef #ah #a #af1jjj #d1jjj #bdj ,jan4 #abdi4aj #c4gc #d4jj #j4cg #dj #aj #a ,sunday4 ,jan4 #acej4jj #d4ad #d4jj #j4cg #aaj #de #b #h1ejj #a1bjj #hdj ,jan4 #addi4aj #d4fe #c4ii #j4ch #baj #ie #c #af1jjj #c1ijj #ejj ,jan4 #aedi4aj #e4bc #c4ii #j4da #cbe #aij #ab #bd1jjj #g1jjj #eej ,jan4 #afej4jj #e4ge #c4ii #j4dc #cfj #baj #cg #bh1jjj #h1ejja1bjj ,jan4 #agdi4aj #f4cd #d4jj #j4de #bdb #abb #bd #fe1jjjae1jjja1gjj ,jan4 #ah --- --- --- --- --- --- --- --- --- --- ,jan4 #aiej4jj #a4ag #d4jj #j4df #aag #dj #ab ,sunday4 ,jan4 #bjej4jj #a4ch #d4jj #j4df #gb #ca #f #a1fjj #a1hjj #cbj ,jan4 #baej4jj #a4fh #c4eg #j4cg #ee #bj #d #e1jjj #dej ,jan4 #bbdi4aj #b4jd #d4jj #j4dd #di #ag #c #c1fjj #fjj #ajj ,jan4 #bcej4jj #b4dg #c4bd #j4cc #dj #ab #c #a1hjj #bij #acj ,jan4 #bddi4aj #c4jc #c4jj #j4cd #dj #aa #b #b1cjj #bgj #fe ,jan4 #beej4jj #c4fa #c4jj #j4ce #ci #aj #b #a1ajj #ahj #fj ,jan4 #bfdi4aj #d4ah #b4ii #j4ce #cb #g #b ,sunday4 ,jan4 #bgej4jj #d4ha #c4jj #j4ce #cb #g #b #cjj #dj #bd ,jan4 #bhdh4bj #e4de #b4ii #j4ce #de #ab #b #a1bjj #ij #ca ,jan4 #bidi4aj #f4ja #b4ii #j4ce #fj #ba #b #a1jjj #bcj #ej ,jan4 #cjdi4aj #f4fb #b4ii #j4cf #eg #bb #b #a1djj #agj #dh ,washed4 ,jan4 #caej4jj #a4cj #b4ii #j4cf #db #ae #b #a1ajj #aij #bc ---------------------------------------- -------------------- ,feb4 #aej4jj #a4ea #b4ii #j4cg #ci #aa #b #gej #dj #ca ,feb4 #bej4jj #a4gh #c4jj #j4cg #bg #g #b ,sunday4 ,feb4 #cdi4aj #b4ac #c4jj #j4cg #bi #f #b #a1cjj #bjj #g ,feb4 #dej4jj #b4fi #c4jj #j4cg #be #e #a #fjj #afj #ah ,feb4 #edi4aj #c4ca #b4ii #j4cg #bd #e #a #gej #adj #da ,feb4 #fej4jj #c4hi #b4ii #j4cg #bj #d #a #b1jjj #ahj #bi ,feb4 #gdh4bj #d4ej #b4ii #j4cg #ag #c #a 444 #ch #ae ,feb4 #hdi4aj #e4aa #b4ii #j4cg #ae #c #a #ijj #ie #bd ,feb4 #idi4aj #e4fe #c4jj #j4ch #ad #c #a ,sunday4 ,feb4 #ajdi4aj #f4dc #b4ii #j4ch #aa #c #a #hej #he #ba ,feb4 #aaej4jj #f4ij #c4jj #j4ch #aj #c #a #a1jjj #gj #bj ,washed4 ,feb4 #abdi4aj #a4bi #b4ii #j4ch #h #b #a #gej #bj #af ,feb4 #acej4jj #a4ej #b4ii #j4ci #i #b #a #gjj #dj #aa ,feb4 #adej4jj #a4hj #b4ii #j4ci #i #b #a #a1bjj #ci #g ,feb4 #aedi4aj #b4ce #c4jj #j4ci #fa #ac #a #e1ejj #fjj #g ,feb4 #afdi4aj #c4bh #b4ii #j4ci #hj #cj #b ,sunday4 ,feb4 #agdh4bj #d4he #b4ii #j4ci #hj #bi #c #cc1jjj #c1hjj #acj ,feb4 #ahdg4cj #f4ci #b4ii #j4ci #acj #dd #c --- #b1fjj #afj ,feb4 #aide4ej #g4cb #b4ih #j4dj #cbj #adc #f #bh1jjj #f1jjj #ahj ,washed4 ,feb4 #bbej4jj #a4dj #c4jj #j4da #he #cj #e ,holiday4 ,feb4 #bcej4jj #a4gg #c4jj #j4da #fj #ba #d ,sunday4 ,feb4 #bddi4aj #b4be #b4ii #j4da #df #ad #c #c1fjj #b1hjj #ij ,feb4 #beej4jj #b4fa #c4jj #j4da #ca #g #b #b1cjj #adj #dg ,feb4 #bfej4jj #c4jf #c4jj #j4da #cj #f #b #c1hjj #adj #de ,feb4 #bgdh4bj #c4fe #b4ii #j4da #cj #e #a #a1cjj #ajj #bb ,feb4 #bhej4jj #d4bd #c4jj #j4da #cg #f #a #a1djj #ajj #dj ,feb4 #bidh4bj #e4bh #b4ii #j4da #abc #eb #b #ac1ejj #dbj #dj ,washed4 ---------------------------------------- -------------------- ,mar4 #add4fj #a4ef #b4ii #j4db #ig #ci #e ,sunday4 ,mar4 #bdh4bj #b4ij #b4ii #j4db #hb #cj #d #h1jjj #cbj #fj ,mar4 #cdf4dj #d4fi #b4ih #j4db #hg #cc #d #aa1jjj #gej #cj ,mar4 #ddg4cj #f4ac #b4ii #j4db #fg #bd #c #f1jjj #bij #cd ,mar4 #edh4bj #g4ca #b4ii #j4db #ei #ai #c #d1djj #bbj #da ,washed4 ,mar4 #fdi4aj #a4ec #b4ii #j4db #gb #bd #b #g1jjj #agj #da ,mar4 #gej4jj #a4ie #c4jj #j4dc #hb #cj #b #i1ejj #baj #cd ,mar4 #hdi4aj #b4fb #b4ii #j4dc #ib #cg #c ,sunday4 ,mar4 #iej4jj #c4ai #c4jj #j4dc #abe #ef #d #aa1jjj #gjj #fe ,mar4 #aj,preliminary filter discontinued and the ,puech system started4 ,table #ag--,record of ,experimental ,filter1 ,puech system4--7,continued47 ,columns3 ,a - ,rates1 millions of gallons per acre daily4 ,b - ,rate1 millions of gallons per acre daily4 ,c - ,loss of head4 ,d - ,applied water4 ,e - ,effluent1 preliminary filter4 ,f - ,effluent1 final filter4 ,g - ,applied water4 ,h - ,effluent1 preliminary filter4 ,i - ,effluent1 final filter4 ,puech system3 ,final ,turbidity4 ,bacteria4 filter4 ,date4 ---------------------------------------- -------------- ,a ,b ,c ,d ,e ,f ,g ,h ,i ---------------------------------------- ----------------- #aijh4 ---------------------------------------- ----------------- ,mar4 #aabfeagj #ij #ec #ahb4iij4ecaee #hj #g #f1ejj #h1ejj #dij ,mar4 #abbfeagj #ij #ec #ahb4iij4fjace #gj #g #e1ijj #f1jjj #cfj ,mar4 #acbfeagj #ij #ec #ahc4jjj4fjabb #eb #f #a1ijj #a1gjj #adj ,mar4 #adbfeagj #ij #ec #ahc4jjj4fa #ig #dj #e #a1hjj #a1fjj #acj ,mar4 #aebfeagj #ij #ec #ahb4iij4fd #gg #ca #d ,sunday4 ,mar4 #afbfeagj #ij #ec #ahc4jjj4fi #fe #bf #c #a1djj #a1bjj #ej ,mar4 #agbdaaee #hb #dh #afb4iij4ga #ei #ai #c #ijj #bjj #de ,mar4 #ahbebafb #hf #ej #agb4iij4ge #fg #bb #b #a1jjj #gjj #cc ,mar4 #aibdaaee #hb #dh #afb4iij4gh #fj #ba #b 444 #hjj #dd ,mar4 #bjbidahiajj #ei #bjb4iij4he #eg #ah #b #a1cjj #fej #cg ,mar4 #babgiagi #ie #ef #aib4iij4ib #fg #ba #b #hjj #fjj #cd ,mar4 #bbbfeagj #ij #ec #ahb4iij4ii #hj #bg #b ,sunday4 ,mar4 #bcbfeagj #ij #ec #ahb4iia4jf #ij #cb #b #d1fjj #a1cjj #cc ,mar4 #bdbfeagj #ij #ec #ahb4iia4ab #hb #cd #c #b1ejj #iej #ch ,mar4 #bebfeagj #ij #ec #ahb4iia4ah #fg #bg #c #a1fjj 444 #cj ,mar4 #bfbfeagj #ij #ec #ahb4iia4bb #fj #bj #c #eej #djj #bd ,mar4 #bgbfeagj #ij #ec #ahc4jja4bc #ei #ah #b #iej #cfj #bh ,mar4 #bhbfeagj #ij #ec #ahc4jja4be #ea #ad #b #fej #bcj #ah ,mar4 #bibfeagj #ij #ec #ahb4iia4bh #ca #f #b ,sunday4 ,mar4 #cjbfeagj #ij #ec #ahb4iia4cf #cj #e #a #ejj #afj #be ,mar4 #cabfeagj #ij #ec #ahb4iia4dc #ci #g #a #gej #adj #bf ---------------------------------------- ----------------- ,apr4 #abfeagj #ij #ec #ahc4jja4dh #dd #i #a #gej #fj #da ,apr4 #bbfeagj #ij #ec #ahb4iia4ef #db #i #a #a1ajj #adj #bf ,apr4 #ccahbjdajh #fd #bbb4iia4fc #da #h #a #a1ejj #dg #aa ,apr4 #dbidahiajj #ei #bjb4iia4gj #ed #ac #a #gjj #hj #ce ,apr4 #ebgiagi #ie #ef #aic4jja4gc #ej #ac #a ,sunday4 ,apr4 #fbgiagi #ie #ef #aib4iia4gf #da #i #a #ddj #fe #ag ,apr4 #gbfeagj #ij #ec #ahc4jja4gh #ce #f #a #fej #fe #cd ,apr4 #hbfeagj #ij #ec #ahc4jja4gi #ci #f #a #eej #dd #aj ,apr4 #ibfeagj #ij #ec #ahc4jja4gi #dj #f #a #cij #cj #be ,apr4 #ajbfeagj #ij #ec #ahc4jja4gg #dj #f #a #ejj #bg #af ,apr4 #aabfeagj #ij #ec #ahc4jja4gh #de #g #a #dcj #bh #bh ,apr4 #abbfeagj #ij #ec #ahb4iia4hj #eb #aa #a ,sunday4 ,apr4 #acbfeagj #ij #ec #ah 444#a4ha #ej #aj #a #dij #ag #bf ,apr4 #ad ,shut down on account of losing water when aqueduct was drained2 also cleaned coarse sand filter4 ,started ,april #bb;d4 ,apr4 #bcbdaaee #hb #dh #af 444#a4hb #bi #d #a #adj #fjj #ch ,apr4 #bdbdaaee #hb #dh #afc4jja4hg #ba #c #a #bjj #a1jjj #ac ,apr4 #bebdaaee #hb #dh #afb4iia4ie #bj #c #a #he #ahj #be ,apr4 #bfbebafb #hf #ej #agc4jja4ie #bd #c #a ,sunday4 ,apr4 #bgbdaaee #hb #dh #afc4jja4ic #ah #b #a #ie #ce #bc ,apr4 #bhbdaaee #hb #dh #afc4jja4if #bj #b #a #gj #bd #ah ,apr4 #bibdaaee #hb #dh #afb4iia4ig #bd #c #a #aaj #ba #bd ,apr4 #cjbdaaee #hb #dh #afb4iib4jc #ba #b #a #gj #be #f ---------------------------------------- ----------------- ,may #abdaaee #hb #dh #afc4jjb4jg #cb #d #a #acj #bj #ah ,may #bbdaaee #hb #dh #afb4iib4ab #bf #c #a #adj #af #ab ,may #cbdaaee #hb #dh #afb4iib4ag #bb #c #a ,sunday4 ,may #dbdaaee #hb #dh #afc4jjb4ai #ai #b #a #he #cj #ag ,may #ebdaaee #hb #dh #afc4jjb4bj #ah #b #a #acj #cc #i ,may #fbdaaee #hb #dh #afb4iib4bc #ah #b #a #bcj #ee #f ,may #gbebafb #hf #ej #agc4jjb4bd #ai #b #a #afj #ge #aj ,may #hbdaaee #hb #dh #afc4jjb4be #ai #b #a #cge #ee #h ,may #icahbjdajh #fd #bbb4iib4bi #ah #b #a #a1bjj #ab #i ,may #ajcahbjdajh #fd #bbb4iib4cj #cj #c #a ,sunday4 ,may #aabfeagj #ij #ec #ahb4iib4cc #fj #aj #a #b1hjj #acj #aa ,may #abbebafb #hf #ej #agb4iib4ci #gj #ae #a #b1ijj #ace #i ,may #acbdaaee #hb #dh #afc4jjb4da #ff #ad #a #a1hjj #aaj #af ,may #adbfeagj #ij #ec #ahc4jjb4ch #de #g #a #b1gjj #fe #ah ,may #aebebafb #hf #ej #agc4jjb4da #ci #e #a #iej #de #ad ,may #afbdaaee #hb #dh #afc4jjb4da #di #g #a #hjj #cb #aj ,may #agbdaaee #hb #dh #afc4jab4cd #df #g #a ,sunday4 ,may #ahbdaaee #hb #dh #afc4jjb4ca #ca #d #a #gjj #bf #f ,may #aibebafb #hf #ej #agc4jjb4bf #cf #d #a #cge #bh #ag ,may #bjbebafb #hf #ej #agc4jjb4bj #da #e #a #dbe #ch #aa ,may #bacddbbaaag #fi #bcc4jjb4ah #cj #c #a #cjj #be #i ,may #bbbdaaee #hb #dh #afc4jab4ag #ec #g #a #iej #bbj #ah ,may #bcbfeagj #ij #ec #ahb4iib4beabg #ch #a #b1djj #fjj #ba ,may #bdccababaab #ff #bbc4jjb4aiaaj #ci #c ,sunday4 ,may #becahbjdajh #fd #bbc4jab4jb #ij #be #c #fjj #cjj #dj ,may #bfbgiagi #ie #ef #aic4jba4hgace #de #c #c1bjj #aaj #cd ,may #bgbfeagj #ij #ec #ahc4jaa4fcaaj #ci #c #ad1ejj #cbj #de ,may #bhbebafb #hf #ej #agc4jaa4da #ij #bg #c #a1jjj #ie #bh ,may #bibebafb #hf #ej #agc4jaa4bd #gj #ag #c #a1ajj #aej #bf ,may #cjbebafb #hf #ej #agc4jaa4jg #ej #i #b ,holiday4 ,may #cabdaaee #hb #dh #afc4jaa4jc #cd #d #b ,sunday4 ---------------------------------------- ----------------- ,june #abebafb #hf #ej #agc4jjj4hc #ce #d #a 444 444 444 ,june #bbdaaee #hb #dh #afc4jjj4gd #ci #e #a 444 444 444 ,june #cbebafb #hf #ej #agc4jjj4fh #ce #d #a 444 444 444 ,june #dbdaaee #hb #dh #afc4jjj4fc #cj #c #a 444 444 444 ,june #ebebafb #hf #ej #agb4iij4fj #cj #c #a 444 444 444 ,june #fbdaaee #hb #dh #afc4jjj4ef #bg #c #a 444 444 444 ,june #gbdaaee #hb #dh #afb4iij4ec #bb #b #a 444 444 444 ,june #hbdaaee #hb #dh #afc4jjj4di #bj #a #a 444 444 444 ,june #ibdaaee #hb #dh #afb4iij4df #bj #a #a 444 444 444 ,june #ajbdaaee #hb #dh #afc4jjj4dd #ag #a #a 444 444 444 ,june #aaccababaab #ff #bbb4ihj4db #ab #a #a 444 444 444 ,june #abcahbjdajh #fd #bbb4ihj4db #aa #a #a 444 444 444 ,june #acbfeagj #ij #ec #ahc4jjj4dj #cf #c #a 444 444 444 ,june #adbebafb #hf #ej #agb4iij4dj #ci #e #a 444 444 444 ,june #aebdaaee #hb #dh #afb4iij4ci #be #c #a 444 444 444 ,june #afbdaaee #hb #dh #afb4iij4dj #cd #c #a 444 444 444 ,june #agbebafb #hf #ej #agb4iij4da #fd #aa #a 444 444 444 ,june #ahbdaaee #hb #dh #afb4iij4db #eg #aa #a 444 444 444 ,june #aibdaaee #hb #dh #afb4iij4db #df #h #a 444 444 444 ,june #bjbdaaee #hb #dh #afb4iij4db #dj #e #a 444 444 444 ,june #babdaaee #hb #dh #afc4jjj4dc #bh #d #a 444 444 444 ,june #bbbdaaee #hb #dh #afb4iij4dc #be #c #a 444 444 444 ,june #bcbdaaee #hb #dh #afb4iij4dc #be #c #a 444 444 444 ,june #bdbdaaee #hb #dh #afb4iij4dc #bi #d #a 444 444 444 ,june #bebdaaee #hb #dh #afb4iij4dc #ah #b #a 444 444 444 ,june #bfbdaaee #hb #dh #afb4hjj4db #ae #a #a 444 444 444 ,june #bgbdaaee #hb #dh #afb4iij4dd #ab #a #a 444 444 444 ,june #bhbdaaee #hb #dh #afb4iij4dd #i #a #a 444 444 444 ,june #bibdaaee #hb #dh #afb4iij4dd #h #a #a 444 444 444 ,june #cjbdaaee #hb #dh #afb4iij4dd #aj #a #a 444 444 444 ---------------------------------------- ----------------- ,july #abdaaee #hb #dh #afc4jjj4de #h #a #a #hj #aj #d ,july #bbdaaee #hb #dh #afc4jjj4df #h #a #j #bij #bd #e ,july #cbdaaee #hb #dh #afc4jjj4dg #h #a #j #cej #de #f ,july #dbdaaee #hb #dh #afb4iij4di #i #a #j 444 444 444 ,july #ecjeaieajc #fa #bac4jjj4ea #aj #a #j 444 444 444 ,july #fbdaaee #hb #dh #afc4jjj4ea #i #a #j #cjj #cf #g ,july #gbdaaee #hb #dh #afb4iij4ec #h #a #j #aaj #aj #c ,july #hbebafb #hf #ej #agc4jjj4ec #i #a #j #he #bb #b ,july #ibdaaee #hb #dh #afc4jjj4ed #h #a #j #he #bf #b ,july #aj444444444444444 444 444 #bjj #c #e ,july #aacjeaieajc #fa #bac4jjj4ef #ab #a #j #ade #g #c ,july #abbdaaee #hb #dh #afb4iij4eh #aa #a #j 444 444 444 ,july #acbdaaee #hb #dh #afc4jjj4fj #aj #a #j #aae #cd #ee ,july #adbdaaee #hb #dh #afb4iij4fb #af #a #j #cjj #ee #cj ,july #aebdaaee #hb #dh #afb4iij4fd #ag #a #j #ahj #cb #bc ,july #afbdaaee #hb #dh #afc4jjj4fg #ac #a #j #ajj #aae #c ,july #agbdaaee #hb #dh #afb4iij4ga #aj #a #j #fe #bge #e ,july #ahbdaaee #hb #dh #afb4iij4gc #aa #a #j #ch #dbe #aj ,july #aibdaaee #hb #dh #afc4jjj4gf #ab #a #j 444 444 444 ,july #bjbdaaee #hb #dh #afb4iij4gi #aj #a #j #ie #ij #gj ,july #babebafb #hf #ej #agb4iij4hc #aj #a #a #gj #ag #d ,july #bbbdaaee #hb #dh #afb4iij4hg #ac #a #a #ddj #h #e ,july #bccjeaieajc #fa #bab4iij4ib #ed #d #a #fej #bf #e ,july #bdccababaaa #ff #bbb4ihj4iicje #fa #a #a1fej 444 444 ,july #bebfeagj #ij #ec #ahb4iha4jhccj #he #a #b1fjj #aae #ae ,july #bfbebafb #hf #ej #agb4iha4babij #gg #b 444 444 444 ,july #bgcjeaieajc #fa #bab4iha4djcce #hg #b #ce1jjj #bej 444 ,july #bhbebafb #hf #ej #agb4iha4fhagj #eb #b #a1bjj #a1cej #ae ,july #bibebafb #hf #ej #agb4igb4adahj #eb #b #b1jjj #fjj #ac ,july #cjbebafb #hf #ej #agb4igb4febcg #ef #b #hjj #a1cjj #ab ,july #cabdaaee #hb #dh #afb4iec4jabej #fj #b #a1jjj #caj #g ,table #ah--,record of ,experimental ,filter ,plant ,no4 #b4 ,preliminary ,filter4 ,final ,filter4 ---------------------------------------- ,date4 ,rate1 ,rate1 millions of ,loss of millions of ,loss of gallons per head4 gallons per head4 acre daily4 acre daily4 ---------------------------------------- -------- #aijg4 ---------------------------------------- -------- ,feb4 #h #ba4ej #j4jd #b4ha #j4ag ,feb4 #i #ba4fj #j4jd #a4ji #j4jf ,feb4 #aj #bj4ij #j4je #a4ei #j4jh ,feb4 #aa #ai4hj #j4je #c4ja #j4ae ,feb4 #ab #ai4gj #j4jf #c4ja #j4ad ,feb4 #ac #ai4fj #j4jf #c4ja #j4ab ,feb4 #ad #bd4gj #j4jg #b4fe #j4ac ,feb4 #ae #cg4bj 444 #c4dj #j4ab ,feb4 #af #cg4cj 444 #c4dj #j4aa ,feb4 #ag,shut down for changes in meters and piping4 ,feb4 #ah 444 444 444 444 ,feb4 #ba #dd4ej 444 #d4cf #j4ai ,feb4 #bb #dh4fj 444 #d4cg #j4af ,feb4 #bc #dh4dj 444 #d4bj #j4ae ,feb4 #bd #dh4cj 444 #d4jb #j4ac ,feb4 #be ,shut down several hours4 #j4ad ,feb4 #bf #dh4fj #j4jd #d4ab #j4ad ,feb4 #bg #ec4bj #j4jd #d4jh #j4ae ,feb4 #bh #eb4hj #j4jd #d4ji #j4ae ---------------------------------------- -------- ,mar4 #a #ec4jj #j4jd #d4aj #j4af ,mar4 #b #ec4cj #j4jd #d4aa #j4af ,mar4 #c #ej4fj #j4je #d4aa #j4af ,mar4 #d #db4dj #j4je #d4ab #j4ag ,mar4 #e #db4gj #j4je #d4aa #j4ag ,mar4 #f #dh4fj #j4jg #d4ac #j4ag ,mar4 #g #ej4ej #j4jh #d4ab #j4ah ,mar4 #h #ea4hj #j4ji #d4ab #j4ah ,mar4 #i #ec4jj #j4aj #d4ab #j4ah ,mar4 #aj #ed4dj #j4ab #d4aa #j4ai ,mar4 #aa #ea4jj #j4ab #d4ab #j4ai ,mar4 #ab #ea4bj #j4ab #d4jg #j4ai ,mar4 #ac #ej4ej #j4ab #d4jj #j4ai ,mar4 #ad #df4ej #j4ab 444 #j4bj ,mar4 #ae #de4hj #j4ab #c4ih #j4bj ,mar4 #af #db4ej #j4ab #c4ig #j4ai ,mar4 #ag #di4cj #j4ad #c4ih #j4ai ,mar4 #ah #eb4fj #j4af #c4ih #j4bj ,mar4 #ai #ec4ej #j4ag #d4ja #j4ai ,mar4 #bj #eb4ij #j4ag #c4ii #j4ah ,mar4 #ba #dh4bj #j4af #d4jj #j4ai ,mar4 #bb #ea4hj #j4ah #d4ja #j4bj ,mar4 #bc #ea4fj #j4ai #d4ja #j4bj ,mar4 #bd #dh4bj #j4ag #d4ja #j4bj ,mar4 #be #dh4ej #j4ah #d4ja #j4bj ,mar4 #bf #de4ij #j4ah #c4ih #j4bj ,mar4 #bg #ej4ej #j4bj #d4jd #j4bj ,mar4 #bh #di4fj #j4bj #c4ib #j4ai ,mar4 #bi #db4bj #j4ag #c4ih #j4ai ,mar4 #cj #dh4jj #j4bb #d4ja #j4ai ,mar4 #ca #di4aj #j4bb #c4ii #j4bj ---------------------------------------- -------- ,apr4 #a #di4aj #j4bd #d4jj #j4bj ,apr4 #b #di4gj #j4be #d4jj #j4bj ,apr4 #c #ea4dj #j4bg #d4jj #j4ba ,apr4 #d #dh4gj #j4bg #d4jj #j4bb ,apr4 #e #dh4aj #j4bg #d4jj #j4bb ,apr4 #f ,shut down awaiting ,mr4 ,maiguen to apply bone-charcoal4 ,apr4 #g ,removed #a4jf in4 of sand4 ,apr4 #h #eb4bj #j4cc #d4je #j4bg ,apr4 #i #df4ij #j4bi #d4jb #j4bi ,apr4 #aj #dg4fj #j4ca #d4jc #j4bh ,apr4 #aa #df4jj #j4cj #d4jd #j4bh ,apr4 #ab #de4dj #j4ca #d4jc #j4bi ,apr4 #ac #de4aj #j4cb #c4ii #j4cb ,apr4 #ad #di4jj #j4cd #d4jj #j4cb ,apr4 #ae #dg4hj #j4ce #c4ii #j4cc ,apr4 #af #dg4dj #j4cf #c4ii #j4cd ,apr4 #ag #de4fj #j4cf #d4jj #j4cd ,apr4 #ah #de4gj #j4cf #d4jj #j4cd ,apr4 #ai #de4fj #j4cg #d4jj #j4cd ,apr4 #bj #de4cj #j4dj #d4jj #j4cf ,apr4 #ba #dg4bj #j4dd #c4ii #j4ch ,apr4 #bb #de4bj #j4db #c4ii #j4ch ,apr4 #bc #dd4ij #j4dd #d4je #j4dj ,apr4 #bd #dj4ej #j4da #d4jb #j4dd ,apr4 #be #ci4fj #j4da #d4jc #j4de ,apr4 #bf #dj4gj #j4dd #d4je #j4de ,apr4 #bg #ci4cj #j4dd #d4jj #j4dd ,apr4 #bh #cd4gj #j4dc #d4je #j4dd ,apr4 #bi #cg4bj #j4de #d4jj #j4db ,apr4 #cj #dc4jj #j4di #d4jj #j4da ---------------------------------------- -------- ,may #a #da4cj #j4di #d4jj #j4da ,may #b #db4dj #j4di #d4jj #j4da ,may #c #dj4gj #j4dh #d4jj #j4dj ,may #d #cc4hj #j4dg #d4jj #j4ci ,may #e #bf4bj #j4dc #d4jj #j4ci ,may #f #bi4jj #j4ch #c4ii #j4cg ,may #g #bg4fj #j4cf 444 #j4cg ,may #h #bd4gj #j4ca #c4ii #j4cg ,washed4 ,may #i #bd4dj #j4jc #c4ih #j4ci ,may #aj #bd4hj #j4jd #d4jj #j4db ,may #aa #ej4jj #j4jf #d4jj #j4dd ,may #ab #ej4jj #j4jh #d4jj #j4dh ,may #ac #ej4jj #j4ji #d4jj #j4dg ,may #ad #ej4jj #j4aj #d4jj #j4df ,may #ae #dh4ej #j4ae #d4jj #j4de ,may #af #dg4jj #j4af #d4jj #j4df ,may #ag #dg4jj #j4af #c4ii #j4dg ,may #ah #dg4jj #j4ai #d4jj #j4dh ,may #ai #dg4jj #j4ba #c4ii #j4ea ,may #bj #df4fj #j4bd #d4jj #j4ec ,may #ba #df4dj #j4bd #d4jj #j4ee ,may #bb #df4dj #j4bg #d4jj #j4eh ,may #bc #df4dj #j4bi #d4jj #j4fa ,may #bd #df4dj #j4cj #d4jj #j4fc ,may #be #df4dj #j4cb #d4jj #j4ff ,may #bf #df4dj #j4cd #c4ii #j4gj ,may #bg #df4dj #j4hf #c4ii #j4gd ,may #bh #df4dj #j4ch #c4ae #j4gf ,may #bi #df4jj #j4dd #c4hh #j4gh ,may #cj #de4fj #j4df #c4ii #j4hf ,may #ca #de4fj #j4df #d4jj #j4ib ---------------------------------------- -------- ,june #a #de4fj #j4df #d4jj #j4ih ,june #b #de4fj #j4dh #d4jj #a4ji ,june #c #de4fj #j4ea #d4jj #a4bj ,june #d #de4fj #j4ed #d4jj #a4cb ,june #e #de4fj #j4ee #d4jj #a4dh ,june #f #de4fj #j4ef #d4ja #c4ff ,june #g #de4jj #j4eg #d4jj #a4hj ,june #h #de4jj #j4eg #d4jj #a4ij ,june #i #de4jj #j4ee #d4ja #b4jj ,june #aj #de4jj #j4ef #d4jj #b4ji ,june #aa #de4jj #j4eh #d4jj #b4ag ,june #ab #de4jj #j4fj #d4ja #b4bg ,june #ac #de4jj #j4fb #d4jj #b4cf ,june #ad #de4jj #j4fc #c4ii #b4di ,june #ae #de4jj #j4fd #c4ii #b4ef ,june #af #dd4gj #j4fe #d4jj #b4fc ,june #ag #dd4dj #j4fd #d4jj #b4fg ,june #ah #de4jj #j4fc #c4ih #b4fi ,june #ai #de4jj #j4fc #d4jj #b4gc ,june #bj #de4jj #j4fb #d4ja #b4gb ,june #ba #de4jj #j4fa #d4ja #b4fh ,june #bb ,shut down to scrape and apply asbestos and coke2 removed #j4gi in4 of sand4 ,june #bc ,applied #h lb4 of asbestos and #aj lb4 of bone-charcoal4 ,june #be #ej4jj #j4ed #d4jj #j4bg ,june #bf #ej4jj #j4eg #d4ja #j4df ,june #bg #ej4jj #j4fc #d4ja #j4ee ,june #bh #ej4jj #j4fe #c4ii #j4fc ,june #bi #ej4jj #j4gj #d4jj #j4gc ,june #cj #ej4jj #j4gg #c4ii #j4hb ---------------------------------------- -------- ,july #a #ej4jj #j4hg #d4jj #j4hj ,july #b #ej4jj #j4ie #d4ja #j4gc ,july #c #ej4jj #a4ja #d4jj #j4ff ,july #d #ej4jj #a4jc #d4jj #j4eh ,july #e #ej4jj #a4jg #c4ii #j4ed ,july #f #ej4jj #a4aj #d4jj #j4eb ,july #g #ej4jj #a4ad #d4jj #j4ej ,july #h #ej4jj #a4af #d4jj #j4dh ,july #i #ej4jj #a4ah #d4jj #j4df ,july #aj #ej4jj #a4bj #c4ii #j4de ,july #aa #ej4jj #a4bj #c4ii #j4de ,july #ab #ej4jj #a4bj #d4ja #j4dd ,july #ac #ej4jj #a4ae #d4jj #j4dg ,july #ad #ej4jj #a4ae #d4jj #j4dh ,july #ae #ej4jj #a4ad #c4ii #j4dh ,july #af #ej4jj #a4ai #d4jj #j4dh ,july #ag #ej4jj #a4ba #d4jj #j4dh ,july #ah #ej4jj #a4ai #c4ii #j4ej ,july #ai #ej4jj #a4af #c4ii #j4eb ,july #bj #ej4jj #a4af #c4ii #j4ef ,july #ba #ej4jj #a4ai #c4ii #j4fc ,july #bb #ej4jj #a4bj #c4ii #j4gg ,july #bc #ej4jj #a4ba #c4ii #j4ic ,july #bd #ej4jj #a4ch #c4ii #a4jg ,july #be #ej4jj #a4ag #c4ii #a4bb ,july #bf #ej4jj #a4jg #d4jj #a4cg ,july #bg #ej4jj #a4aa #d4jj ,july #bh #ej4jj #a4bb #c4ih #a4fe ,july #bi #ej4jj #a4ba #d4jj #a4hb ,july #cj #ej4jj #a4bj #c4ii #a4ih ,july #ca #ej4jj #a4bj #c4ii #b4aa ---------------------------------------- -------- ,aug4 #a #ea4jj #a4ba #c4ii #b4bg ,aug4 #b #ea4jj #a4ba #c4ii #b4dc ,aug4 #c #ea4jj #a4ba #d4jj #b4ff ,aug4 #d #ej4jj #a4ba #c4ii #b4ie ,aug4 #e #ej4jj #a4ba #c4ih #c4bb ,aug4 #f #ej4jj #a4bb #c4ih #c4ej ,aug4 #g #ej4jj #a4ba #c4ii #c4gd ,aug4 #h #dh4bj #a4bj 444 #d4ji ,aug4 #i #ej4jj #a4ah 444 #d4de ,aug4 #aj #dg4cj #a4af 444 #d4fg ,aug4 #aa ,shut down to drain and scrape sand filter2 ,o4#i in4 depth over all4 ,aug4 #af,out of service all the rest of month washing sponge and asbestos4 ---------------------------------------- -------- ,sept4 #c #ej4jj #j4jb #d4jj #j4af ,sept4 #d #ej4jj #j4jb #c4ii #j4ad ,sept4 #e #ej4jj #j4jb #d4ja #j4ac ,sept4 #f #df4dj #j4jb #d4jj #j4ab ,sept4 #g #ej4jj #j4jc #d4jj #j4aa ,sept4 #h #df4dj #j4jd #c4ii #j4aa ,sept4 #i #ej4jj #j4je #d4ij #j4aa ,sept4 #aj #ej4jj #j4je #d4jj #j4aa ,sept4 #aa #ej4jj #j4jf #d4jj #j4aa ,sept4 #ab #ej4jj #j4jg #d4jj #j4ab ,sept4 #ac #ej4jj #j4jh #d4jj #j4ab ,sept4 #ad #ej4jj #j4ji #d4ja #j4ab ,sept4 #ae #dh4bj #j4aa #d4jj #j4ab ,sept4 #af #ea4jj #j4ac #d4jj #j4ab ,sept4 #ag #ej4jj #j4ad #d4jj #j4ab ,sept4 #ah #di4aj #j4ad #d4jj #j4ac ,sept4 #ai #ej4jj #j4ae #d4jj #j4ac ,sept4 #bj #di4aj #j4ag #d4jj #j4ac ,sept4 #ba #di4aj #j4ah #d4jj #j4ac ,sept4 #bb #dh4bj #j4bj #d4jj #j4ac ,sept4 #bc #di4aj #j4ai #d4jj #j4ac ,sept4 #bd #df4dj #j4ai #c4ii #j4ad ,sept4 #be #df4dj #j4bj #d4jj #j4ad ,sept4 #bf #de4fj #j4bd #d4jj #j4ae ,sept4 #bg #dd4hj #j4bg #d4jj #j4af ,sept4 #bh #df4dj #j4cj #c4ii #j4af ,sept4 #bi #df4dj #j4ca #c4ii #j4af ,sept4 #cj #df4dj #j4ca #d4jj #j4ag ---------------------------------------- -------- ,oct4 #a #dh4bj #j4cc #d4jj #j4ah ,oct4 #b #ej4jj #j4cc #d4ja #j4ai ,oct4 #c #dh4bj #j4cc #d4jj #j4ai ,oct4 #d #dh4bj #j4cd #d4jj #j4ai ,oct4 #e #ej4jj #j4ch #d4jj #j4ai ,oct4 #f #dh4bj #j4da #d4jj #j4ai ,oct4 #g #dh4bj #j4db #d4jj #j4ai ,oct4 #h #ej4jj #j4db #d4jj #j4ai ,oct4 #i #dd4hj #j4dj #d4jj #j4ai ,oct4 #aj #dh4bj #j4db #d4jj #j4ai ,oct4 #aa #dh4bj #j4dc #d4jj #j4bj ,washed4 ,oct4 #ab #ej4jj #j4ad #d4jj #j4bj ,oct4 #ac #dg4cj #j4ae #d4jj #j4ba ,oct4 #ad #ej4jj #j4ah #d4jj #j4bb ,oct4 #ae #ec4jj #j4bj #d4jj #j4bc ,oct4 #af #ej4jj #j4bj #d4jj #j4bd ,oct4 #ag #ej4jj #j4ba #d4jj #j4be ,oct4 #ah #ej4jj #j4ba #d4jj #j4be ,oct4 #ai #ej4jj #j4ba #d4jj #j4be ,oct4 #bj #ej4jj #j4bb #d4jj #j4be ,oct4 #ba #ej4jj #j4bc #d4jj #j4be ,oct4 #bb #ej4jj #j4bd #d4jj #j4bf ,oct4 #bc #ej4jj #j4be #d4jj #j4bf ,oct4 #bd #ej4jj #j4bf #d4jj #j4bf ,oct4 #be #ej4jj #j4bg #d4jj #j4bg ,oct4 #bf #ej4jj #j4bh #d4jj #j4bg ,oct4 #bg #ej4jj #j4bi #d4jj #j4bg ,oct4 #bh #ej4jj #j4cj #d4jj #j4bg ,oct4 #bi #ej4jj #j4ca #d4jj #j4bg ,oct4 #cj #ej4jj #j4cb #d4jj #j4bg ,oct4 #ca,out of commission4 #d-;in supply pipe stopped up4 ---------------------------------------- -------- ,nov4 #d #ej4jj #j4af #d4jj #j4bh ,nov4 #e #ej4jj #j4ag #d4jj #j4bh ,nov4 #f #ej4jj #j4ah #d4jj #j4bi ,nov4 #g #ej4jj #j4bj #d4jj #j4cj ,nov4 #h #ej4jj #j4ba #d4jj #j4cb ,nov4 #i #ej4jj #j4bb #d4jj #j4cd ,nov4 #aj #ej4jj #j4bc #d4jj #j4cf ,nov4 #aa #ej4jj #j4bd #c4df #j4ch ,nov4 #ab #ej4jj #j4bf #c4ii #j4dj ,nov4 #ac #ej4jj #j4bg #d4jj #j4dd ,nov4 #ad #ej4jj #j4bh #d4jj #j4di ,nov4 #ae #ej4jj #j4bi #d4jj #j4ee ,nov4 #af #ej4jj #j4cj #d4jj #j4fe ,nov4 #ag #ej4jj #j4ca #c4ih #j4hj ,nov4 #ah #ej4jj #j4cb #c4ii #j4ih ,nov4 #ai #ej4jj #j4cd #c4ii #a4bf ,nov4 #bj #ej4jj #j4ce #c4ih #a4fd ,nov4 #ba #ej4jj #j4cf #c4ii #b4jc ,nov4 #bb #ej4jj #j4cg #c4ih #b4cc ,nov4 #bc #ej4jj #j4ch #c4ii #b4fj ,nov4 #bd #ej4jj #j4dj #c4ih #b4he ,nov4 #be #dh4bj #j4de #c4ih #c4aj ,nov4 #bf #ej4jj #j4di #c4ih #c4fb ,nov4 #bg #ej4jj #j4ea #c4ii #d4ae ,nov4 #bh #ej4jj #j4ed #c4hd #d4dd ,nov4 #bi #ej4jj #j4ee #c4fg #d4ee ,nov4 #cj #ej4jj #j4ef #c4dd #d4fe ---------------------------------------- -------- ,dec4 #b ,shut down to scrape sand filter4 ,dec4 #f #ej4jj #j4fd #d4jj #j4df ,dec4 #g #ej4jj #j4fd #d4jj #j4ci ,dec4 #h #ej4jj #j4fd #d4ja #j4ce ,dec4 #i #ej4jj #j4fe #d4ja #j4cc ,dec4 #aj #ej4jj #j4fe #d4jj #j4cc ,dec4 #aa #dg4cj #j4fd #d4jj #j4ce ,dec4 #ab #df4dj #j4gj #c4ih #j4ci ,dec4 #ac #ej4jj #j4gi #c4ih #j4di ,dec4 #ad #eb4jj #j4hd #c4ig #j4fe ,dec4 #ae #di4aj #j4hd #c4ih #j4gg ,dec4 #af #di4aj #j4hf #c4ig #j4hd ,dec4 #ag #di4aj #j4hh #c4ih #j4ia ,dec4 #ah #dh4bj #j4hi #c4ih #j4id ,dec4 #ai #ej4jj #j4ia #c4ih #j4ig ,dec4 #bj #di4aj #j4ib #c4ih #a4jc ,dec4 #ba #ej4jj #j4id #c4ih #a4jh ,dec4 #bb #ej4jj #j4ig #c4ih #a4ac ,dec4 #bc #ej4jj #j4ie #c4ih #a4ai ,dec4 #bd #dg4cj #j4ic #c4ih #a4bh ,dec4 #be #dd4aj #j4ia #c4ig #a4dg ,dec4 #bf #df4dj #a4ja #c4ig #a4fc ,dec4 #bg #ej4jj #a4aa #c4ih #a4ha ,dec4 #bh #dh4bj #a4ab #c4ii #a4hg ,dec4 #bi #ej4jj #a4ad #c4ii #a4he ,dec4 #cj #di4aj #a4ae #c4ih #a4hf ,dec4 #ca #ej4jj #a4ag #d4jj #a4hg ---------------------------------------- -------- #aijh4 ---------------------------------------- -------- ,jan4 #a #ej4jj #a4ah #c4ih #a4ij ,jan4 #b #ej4jj #a4ah #c4ii #a4id ,jan4 #c #ej4jj #a4ai #c4ih #a4ih ,washed4 ,jan4 #d #ej4jj #j4ag #c4ig #b4ji ,jan4 #e #ej4jj #j4ah #c4ih #b4bb ,jan4 #f #ej4jj #j4ai #c4ih #b4bh ,jan4 #g #ej4jj #j4bj #c4ih #b4cg ,jan4 #h #ej4jj #j4ba #c4ii #b4dc ,jan4 #i #ej4jj #j4bc #c4ih #b4eb ,jan4 #aj #ej4jj #j4bd #c4ii #b4ff ,jan4 #aa #ej4jj #j4bg #c4ih #b4gd ,jan4 #ab #ej4jj #j4bh #c4ih #b4hc ,jan4 #ac #di4aj #j4cj #c4ih #b4ic ,jan4 #ad #dh4bj #j4cc #c4ii #c4jd ,jan4 #ae #df4dj #j4ce #c4ih #c4ba ,jan4 #af #ej4jj #j4dj #c4ih #c4di ,jan4 #ag #ej4jj #j4dc #c4ih #c4hf ,jan4 #ah #ej4jj #j4df #c4ia #c4ii ,jan4 #ai 444 444 444 444 ,jan4 #bj ,scraped4 ,jan4 #ba #ej4jj #j4dh #c4jj #j4gf ,jan4 #bb #ej4jj #j4dh #c4ja #j4fj ,jan4 #bc #ej4jj #j4di #c4jj #j4eg ,jan4 #bd #ej4jj #j4di #b4ii #j4fj ,jan4 #be #ej4jj #j4ej #b4ii #j4fe ,jan4 #bf #ej4jj #j4ej #b4ih #j4fi ,jan4 #bg #ej4jj #j4ea #b4ii #j4gf ,jan4 #bh #ej4jj #j4eb #b4ii #j4hb ,jan4 #bi #ej4jj #j4ee #b4ii #j4ij ,jan4 #cj #ej4jj #j4eg #b4ih #j4ih ,jan4 #ca #ej4jj #j4eh #b4ih #a4jh ---------------------------------------- -------- ,feb4 #a #ej4jj #j4ei #b4ii #a4af ,feb4 #b #di4aj #j4fj #b4ii #a4bb ,feb4 #c #di4aj #j4fa #b4ih #a4cj ,feb4 #d #ej4jj #j4fd #b4ii #a4dj ,feb4 #e #ej4jj #j4ff #b4ii #a4ej ,feb4 #f #ej4jj #j4fg #b4ii #a4ee ,feb4 #g #ej4jj #j4fh #c4jj #a4ef ,feb4 #h #ej4jj #j4fi #c4jj #a4ec ,feb4 #i #ej4jj #j4ga #c4jj #a4ed ,feb4 #aj #ej4jj #j4gb #b4ii #a4fj ,feb4 #aa #ej4jj #j4gd #b4ii #a4fb ,feb4 #ab #ej4jj #j4ge #b4ih #a4fh ,feb4 #ac #ej4jj #j4gf #b4ii #a4gd ,feb4 #ad #dh4bj #j4gf #b4ii #a4gg ,feb4 #ae #ea4hj #j4gi #b4ii #a4hi ,feb4 #af #dh4bj #j4gi #b4ii #b4jh ,feb4 #ag #dh4bj #j4ha #b4ii #b4bd ,feb4 #ah #dg4cj #j4hb #b4ii #b4ca ,feb4 #ai #ea4hj #j4ib #b4ii #b4de ,feb4 #bj #eb4gj #j4ii #b4ii #b4fa ,feb4 #ba #ea4hj #a4jc #b4ii #b4fh ,feb4 #bb #ej4ij #a4jg #b4ii #b4gb ,feb4 #bc #ej4jj #a4ji #b4ii #b4gf ,feb4 #bd #ea4hj #a4ab #b4ii #b4hj ,feb4 #be #ej4jj #a4ad #b4ii #b4hd ,feb4 #bf #ej4jj #a4ag #c4jj #b4hg ,feb4 #bg #dh4bj #a4ah #b4ii #b4ij ,feb4 #bh #dg4cj #a4ai #b4ii #b4id ,feb4 #bi #ea4hj #a4bc #b4ii #c4ja ---------------------------------------- -------- ,mar4 #a #dh4bj #a4bj #b4ih #b4ii ,mar4 #b #ej4jj #a4bh #b4ii #c4ab ,mar4 #c #ej4ij #a4cb #b4ih #c4bb ,mar4 #d #ej4jj #a4cc #b4ii #c4bh ,mar4 #e #ej4jj #a4ce #b4ii #c4cb ,mar4 #f ,discontinued2 sand filter being used for sedimentation experiments4 ,table #ah--7;,continued47 ,turbidity4 ,bacteria4 ---------------------------------------- ---------- ,date4 ,applied,effluent1,effluent1,applied,eff luent1,effluent1 water4 pre- final water4 pre- final liminary filter4 liminary filter4 filter filter4 ---------------------------------------- ------------------ #aijg4 ---------------------------------------- ------------------ ,feb4 #h 444 444 444 #a1ajj #b1ajj 444 ,feb4 #i 444 444 444 #bjj #eej #b1ajj ,feb4 #aj 444 444 444 444 444 444 ,feb4 #aa #ab #f #b #fjj #a1afj #a1ajj ,feb4 #ab #ab #e #b #fej #djj #gjj ,feb4 #ac #ae #e #b #ffj #ijj #gjj ,feb4 #ad #ae #f #b #fej #a1ajj #ijj ,feb4 #ae #ab #e #b #fjj #hjj #hej ,feb4 #af #ad #d #b #hej #iej #fjj ,feb4 #ag ,shut down for changes in meters and piping4 ,feb4 #ah 444 444 444 #a1bjj 444 #fjj ,feb4 #ba #bj #f #b #a1hjj #a1djj #hjj ,feb4 #bb #ae #d #b ,holiday4 ,feb4 #bc #bj #g #b #a1fjj #gej #chj ,feb4 #bd #bj #aj #c ,sunday4 ,feb4 #be #bj #aj #c #a1djj #a1jjj #dej ,feb4 #bf #bj #aj #c #gjj #hjj #bfj ,feb4 #bg #ag #h #c #gjj #gjj #bij ,feb4 #bh #ae #h #c #hjj #fej #ejj ---------------------------------------- ------------------ ,mar4 #a #ae #h #c #fej #eej #bjj ,mar4 #b #ae #g #c #a1jjj #hjj #cjj ,mar4 #c #ca #aa #c ,sunday4 ,mar4 #d #ce #ae #f #a1bjj #a1ejj #cfj ,mar4 #e #ace #eb #aj #ac1jjj #hej 444 ,mar4 #f #ace #ed #ab #ah1jjj #h1jjj 444 ,mar4 #g #ajb #df #h #bd1jjj #f1ejj #a1hjj ,mar4 #h #ajj #dj #f #bb1jjj #f1jjj #a1fjj ,mar4 #i #ij #dj #e #bd1jjj #f1jjj #hjj ,mar4 #aj #hb #ci #f ,sunday4 ,mar4 #aa #fh #cb #g #ah1jjj #d1cjj #bdj ,mar4 #ab #df #be #e #aa1jjj #d1fjj #baj ,mar4 #ac #dj #bj #e #i1jjj #a1ejj #bjj ,mar4 #ad #ci #bj #d #e1ejj #a1bjj #ij ,mar4 #ae #ce #ah #d #f1ejj #a1ajj #aej ,mar4 #af #fj #bd #d #e1jjj #hjj #afj ,mar4 #ag #ace #de #e ,sunday4 ,mar4 #ah #agj #ei #i #i1jjj #a1gjj #ajj ,mar4 #ai #abe #ea #h #g1jjj #a1jjj #abj ,mar4 #bj #ajb #dj #f #d1hjj #gjj #ge ,mar4 #ba #abe #db #e #h1ejj #a1ajj #ij ,mar4 #bb #aij #hb #e #g1ejj #a1ajj #ee ,mar4 #bc #ahj #ge #f #g1ejj #a1cjj #ij ,mar4 #bd #adj #fh #g ,sunday4 ,mar4 #be #hh #dj #e #d1djj #ijj #ge ,mar4 #bf #fb #cb #d #c1fjj #gej #ij ,mar4 #bg #dg #be #d #b1bjj #djj #fj ,mar4 #bh #ce #af #c #a1cjj #cej #ee ,mar4 #bi #bf #ab #c #gjj #ahj #bj ,mar4 #cj #be #g #c #caj #bbj #ci ,mar4 #ca #ba #f #b ,sunday4 ---------------------------------------- ------------------ ,apr4 #a #bj #f #b #fjj #aaj #ch ,apr4 #b #bd #f #b #bgj #aaj #bi ,apr4 #c #bd #f #b #dfj #he #ca ,apr4 #d #bj #f #b #bhj #fj #bb ,apr4 #e #bj #e #b #dej #gj #dj ,apr4 #f,shut down awaiting ,mr4 ,maiguen to apply bone-charcoal4 ,apr4 #g,removed #a4jf in4 of sand4 ,sunday4 ,apr4 #h #ah #d #c #ccj 444 444 ,apr4 #i #ah #d #b #adj #fj #cb ,apr4 #aj #cj #d #a #gej #abj #bh ,apr4 #aa #ff #g #b #d1jjj 444 #cb ,apr4 #ab #gb #bj #c #ad1jjj #b1ijj #he ,apr4 #ac #hj #cj #c #ac1jjj #b1ejj #ie ,apr4 #ad #gg #ce #d ,sunday4 ,apr4 #ae #fb #ca #d #g1jjj #a1ajj #fj ,apr4 #af #dg #bg #d #c1fjj #fej #ca ,apr4 #ag #ci #ba #c #a1fjj #afj #ch ,apr4 #ah #cj #ac #b #a1haj #baj #db ,apr4 #ai #be #i #b #gij #aij #cd ,apr4 #bj #bj #f #b #edj #hg #bc ,apr4 #ba #bj #d #b ,sunday4 ,apr4 #bb #ah #c #a #bce #ee #bb ,apr4 #bc #ae #c #a #agj #de #af ,apr4 #bd #ai #b #a #aej #ad #ad ,apr4 #be #cd #c #a #gjj #ab #bc ,apr4 #bf #df #d #a #a1bjj #hj #af ,apr4 #bg #eb #d #a #a1gjj #afj #bc ,apr4 #bh #de #e #a ,sunday4 ,apr4 #bi #dd #f #a #fjj #fj #aj ,apr4 #cj #ci #g #a #eej #ee #ae ---------------------------------------- ------------------ ,may #a #ca #f #a #ejj #hj #ag ,may #b #bd #e #a #ejj #hj #ai ,may #c #ai #d #a #bhj #ge #dh ,may #d #af #c #a #djj #hj #i ,may #e #ae #a #a ,sunday4 ,may #f #ac #b #a #cij #ajj #fe ,may #g #ab #b #a #aij #fj #ai ,may #h #aj #b #a 444 444 444 ,washed4 ,may #i #aj #b #a #cij #fe #aj ,may #aj #aj #b #a #cjj #hj #ah ,may #aa #ab #b #a #cij #aaj #ab ,may #ab #ag #b #a ,sunday4 ,may #ac #ce #c #a #fjj #ajj #ah ,may #ad #ci #d #a #ejj #fe #ae ,may #ae #ag #c #a #ejj #gj #af ,may #af #bd #c #a #bij #gj #af ,may #ag #ah #c #a #bfj #dj #i ,may #ah #ae #b #a #aij 444 #ag ,may #ai #ab #b #a ,sunday4 ,may #bj #ab #b #a #bfj #dj #ac ,may #ba #af #b #a #bfj #fe #i ,may #bb #bj #b #a #bhj #ce #ab ,may #bc #ae #b #a #acj #ce #aj ,may #bd #ae #b #a #agj #bf #f ,may #be #ae #b #a #cdj #hj #ac ,may #bf #ah #b #a ,sunday4 ,may #bg #ac #b #a #baj #hj #g ,may #bh #af #b #a #bfj #gj #aj ,may #bi #af #b #a #ejj #ee #ab ,may #cj #ad #b #a ,holiday4 ,may #ca #ag #b #a #chj #fe #aa ---------------------------------------- ------------------ ,june #a #ae #b #a #ijj #dh #aj ,june #b #ag #b #a ,sunday4 ,june #c #bd #b #a #eej #ge #af ,june #d #cg #c #a #f1ejj 444 #bb ,june #e #fe #e #a #c1bjj #adj #ai ,june #f #gg #af #a #a1ejj #baj #ad ,june #g #fd #bg #a #b1ajj #bcj #bj ,june #h #df #bb #a #fjj #bdj #cc ,june #i #dd #ah #a ,sunday4 ,june #aj #cf #ab #a #bdj #aaj #dc ,june #aa #cj #h #a #bhj #acj #fj ,june #ab #cd #h #a #ccj #aej #fj ,june #ac #ce #aj #a #dhj 444 #abj ,june #ad #ca #i #a #ddj 444 #fe ,june #ae #cb #h #a #dbj 444 #di ,june #af #bf #g #a ,sunday4 ,june #ag #bf #f #a #cdj #bgj #ee ,june #ah #ca #g #a #ddj #adj #fe ,june #ai #cg #aj #a #ejj #aaj #bd ,june #bj #cj #i #a #ccj #gj #cd ,june #ba #be #g #a #agj #acj #fj ,june #bb ,shut down to scrape and apply asbestos and coke2 removed #j4gi in4 of sand4 ,june #bc;,applied #h lb4 of asbestos and #aj lb4 of bone-charcoal4 ,june #be #acj #de #a #djj 444 444 ,june #bf #hb #cg #a #gej #eej #ce ,june #bg #fe #bf #a 444 #a1bjj #adj ,june #bh #dg #ba #a 444 #a1bjj #bf ,june #bi #cg #i #a #bbj #hjj #bb ,june #cj #cj #h #a ,sunday4 ---------------------------------------- ------------------ ,july #a #cj #h #a #djj #ij #cg ,july #b #cb #i #a #ahj #bcj #be ,july #c #cf #aj #a #cej #hj #eh ,july #d #dd #ab #a ,holiday4 ,july #e #bd #ad #a #eej #acj #dg ,july #f #ci #ab #a #bej #aaj #cc ,july #g #cd #aj #a ,sunday4 ,july #h #be #g #a #bbj #aij #ad ,july #i #bb #e #a #ej #cj #c ,july #aj #dg #aa #a ,lost4 ,lost4 ,lost4 ,july #aa #ij #cj #a #aej #adj #ab ,july #ab #ig #ce #a #cjj #aaj #bj ,july #ac #ij #ci #a #bbj #abj #ad ,july #ad #ij #dj #a ,sunday4 ,july #ae #ie #dj #a #cge #cbj #ai ,july #af #abj #de #a ,lost4 #aej #ab ,july #ag #he #db #a #bgj #fj #e ,july #ah #ef #cb #a #a1fge #bc #ci ,july #ai #da #bj #a #dej #bjj #ac ,july #bj #fb #bi #a #cjj #bbj #h ,july #ba #fb #ca #a ,sunday4 ,july #bb #hj #cf #a #a1djj #gjj #i ,july #bc #aje #dj #a #c1gjj #cgj #be ,july #bd #ie #dj #a #ggj #bfj #ca ,july #be #gg #cb #a #bej #bcj #c ,july #bf #fg #bi #a #adj #ij #ab ,july #bg #ed #be #a #cjj #ahj #f ,july #bh #df #ai #a ,sunday4 ,july #bi #cf #af #a #dgj #bcj #ah ,july #cj #bi #aa #a ,plates lost4 ,july #ca #ba #i #a ,july ---------------------------------------- ------------------ ,aug4 #a #af #f #a ,plates lost4 ,aug4 #b #ae #d #a #acj #acj #d ,aug4 #c #af #c #a #abj #hj #d ,aug4 #d #ba #c #a ,sunday4 ,aug4 #e #bi #c #a #bcj #baj #d ,aug4 #f #cd #d #a #he #cbj #ai ,aug4 #g #ba #d #a #bjj ,lost4 #ai ,aug4 #h #ai #d #a #ajj #aej #ag ,aug4 #i #af #c #a #ge #bbj #i ,aug4 #aj #bd #c #a #fj #bej #aj ,aug4 #aa ,shut down to drain and scrape sand filter2 ,o4#i in4 depth over all4 ,aug4 #af ,out of service all the rest of month washing sponge and asbestos4 ---------------------------------------- ------------------ ,sept4 #c #ab #e #a #cjj 444 444 ,sept4 #d #af #f #a #fjj #bfj #cgj ,sept4 #e #cd #f #a #cfj #ga #afe ,sept4 #f #afj #eb #a #ae1jjj #a1ijj #abj ,sept4 #g #fd #bf #a #b1jjj #agj #fb ,sept4 #h #ef #be #a ,sunday4 ,sept4 #i #ei #be #a #bbj #ac #ai ,sept4 #aj #eg #ba #a #ah1jjj #ajj #bd ,sept4 #aa #fe #be #a #b1gjj #aej #be ,sept4 #ab #gb #bf #a #a1jjj #aij #cf ,sept4 #ac #hg #cj #a #b1cjj 444 #ce ,sept4 #ad #gb #bg #a #b1djj #acj #bcj ,sept4 #ae #fe #be #a ,sunday4 ,sept4 #af #fe #be #a ,lost4 ,lost4 #bg ,sept4 #ag #eb #ba #a #dbj #fj #bi ,sept4 #ah #fj #ah #a #ijj #hj #da ,sept4 #ai #he #bb #a #b1jjj 444 #ai ,sept4 #bj #ajj #bi #a #d1bjj #cjj #bh ,sept4 #ba #abj #cd #a #a1ajj #afj #cj ,sept4 #bb #acg #da #a ,sunday4 ,sept4 #bc #aab #cg #a #b1djj #ij #cd ,sept4 #bd #ajj #ce #a #d1jjj #baj #ab ,sept4 #be #dcb #hj #a #ef1jjj #eaj #bg ,sept4 #bf #che #hj #d #a1cjj #dej #ee ,sept4 #bg #bde #gj #c #d1jjj #bdj #da ,sept4 #bh #abg #df #b #ae1jjj #dcj #cg ,sept4 #bi #aje #da #b ,sunday4 ,sept4 #cj #aae #db #a ,lost4 #a1fjj #aaj ---------------------------------------- ------------------ ,oct4 #a #hb #cf #a #fjj #fjj #abj ,oct4 #b #fe #bg #a #d1djj #agj #dg ,oct4 #c #ei #cd #a #ijj #baj #dd ,oct4 #d #ee #bj #a #hej #bjj #cg ,oct4 #e #i #ba #a #b1jjj #aej #cd ,oct4 #f #ei #bd #a ,sunday4 ,oct4 #g #eeb #ag #a #a1bej #bjj #bh ,oct4 #h #ed #af #a #aa1jjj #baj #bh ,oct4 #i #ea #af #a #b1jjj #caj #bi ,oct4 #aj #ej #ae #a #hjj #bbj #af ,oct4 #aa #dg #ac #a #b1jjj #caj #df ,washed4 ,oct4 #ab #cf #aa #a #a1bjj #cgj #be ,oct4 #ac #dj #ae #a ,sunday4 ,oct4 #ad #dg #ai #a #a1bjj #cij #bb ,oct4 #ae #da #af #a #ijj #adj #af ,oct4 #af #ce #ab #a ,lost4 #caj #ah ,oct4 #ag #cj #h #a #eej #ahj #g ,oct4 #ah #be #f #a #bfj #ajj #cc ,oct4 #ai #be #f #a #gej #bbj #ae ,oct4 #bj #bj #e #a ,sunday4 ,oct4 #ba #ai #e #a #dhj #abj #aa ,oct4 #bb #ah #d #a #bcj #gj #g ,oct4 #bc #ae #c #a #bej #abj #ab ,oct4 #bd #ae #c #a #cjj #hj #ab ,oct4 #be #ae #b #a #dej #fj #ae ,oct4 #bf #ae #b #a #dej ,lost4 #ad ,oct4 #bg #ac #b #j ,sunday4 ,oct4 #bh #ac #b #j #aij #aaj #i ,oct4 #bi #be #b #j #chj 444 444 ,oct4 #cj #ba #c #j 444 444 444 ,oct4 #ca ,out of commission4 #d-;in4 supply pipe stopped up4 ---------------------------------------- ------------------ ,nov4 #d #abe #aa #a 444 444 444 ,nov4 #e #ahe #fa #a #f1jjj #c1jjj #bbj ,nov4 #f #agj #ff #a #e1jjj #a1ajj #aej ,nov4 #g #ajj #de #a #ad1jjj #a1fjj #abj ,nov4 #h #ie #db #a #a1ijj #b1jjj #bi ,nov4 #i #hj #cf #a #d1jjj #b1jjj #aaj ,nov4 #aj #fg #bi #a ,sunday4 ,nov4 #aa #eb #bj #a #a1ijj #dfj #afj ,nov4 #ab #dj #ac #a #g1ejj #a1ajj #aaj ,nov4 #ac #cf #aj #a #a1fjj #eej #ej ,nov4 #ad #db #ac #a #b1gjj #iej #dh ,nov4 #ae #ce #aa #a #a1hjj #ijj #di ,nov4 #af #bf #g #a #a1ajj #cfj #ce ,nov4 #ag #bj #e #a ,sunday4 ,nov4 #ah #ag #d #a #a1fjj #bjj #ce ,nov4 #ai #af #c #a #a1cjj #djj #ee ,nov4 #bj #de #d #a #f1ejj #c1ejj #bjj ,nov4 #ba #eb #ab #a #i1ijj #d1ejj #acj ,nov4 #bb #fe #bd #a #aj1jjj #e1ejj #bbj ,nov4 #bc #di #ai #a #ah1jjj #c1ejj #ajj ,nov4 #bd #acd #cb #a ,sunday4 ,nov4 #be #bbe #hg #b #ej1jjj #ai1jjj #cdj ,nov4 #bf #bcg #ij #b #dj1jjj #aa1jjj #bbj ,nov4 #bg #ahe #gg #b #af1jjj #g1ejj #caj ,nov4 #bh #acj #eg #b ,holiday4 ,nov4 #bi #hj #cf #a #aj1jjj #b1bjj #hj ,nov4 #cj #ed #be #a #c1hjj #b1bjj #ee ---------------------------------------- ------------------ ,dec4 #b,shut down to scrape sand filter4 ,dec4 #f #af #c #a ,dec4 #g #ad #c #a #b1djj #a1bjj #dij ,dec4 #h #ab #b #a ,sunday4 ,dec4 #i #aa #b #a #a1bjj #dbj #fj ,dec4 #aj #ab #b #a #hjj #iej #ff ,dec4 #aa #bee #hd #c #f1ejj #a1fjj #adj ,dec4 #ab #bab #ajj #f #dh1jjj #ae1jjj #a1hjj ,dec4 #ac #die #bag #i #db1jjj #bj1jjj #a1fjj ,dec4 #ad #ceg #afg #i #di1jjj #i1ejj #a1bjj ,dec4 #ae #aeg #gf #f ,sunday4 ,dec4 #af #ij #db #d #ai1jjj #hjj #gjj ,dec4 #ag #gj #ca #b #ba1jjj #ah1jjj #a1fjj ,dec4 #ah #di #ba #b #f1ejj #g1jjj #fjj ,dec4 #ai #ci #ac #a ,lost4 ,lost4 ,lost4 ,dec4 #bj #db #af #a ,dec4 ,dec4 ,dec4 #ba #bf #g #a ,dec4 ,dec4 ,dec4 #bb #bj #e #a ,sunday4 ,dec4 #bc #cd #i #a #a1djj #ejj #afj ,dec4 #bd #aie #ge #b #i1jjj #a1gjj #acj ,dec4 #be #dde #baj #i ,holiday4 ,dec4 #bf #cgj #agb #g #ea1jjj #h1jjj #bej ,dec4 #bg #bde #aaj #e #ee1jjj #e1fjj #baj ,dec4 #bh #ajb #df #c #aj1jjj #d1ejj #adj ,dec4 #bi #ge #cb #b ,sunday4 ,dec4 #cj #ef #bd #b #d1djj #a1ijj #aij ,dec4 #ca #ci #ae #a #ad1jjj #a1cjj #fj ---------------------------------------- ------------------ #aijh4 ---------------------------------------- ------------------ ,jan4 #a #ca #h #a 444 444 444 ,jan4 #b #ci #aa #a #d1djj #gej #de ,jan4 #c #cf #aa #a #c1ajj #a1fjj #gj ,washed4 ,jan4 #d #cb #i #a #b1djj #a1bjj #dc ,jan4 #e #bf #f #a ,sunday4 ,jan4 #f #bj #e #a #fjj #fjj #di ,jan4 #g #bj #e #a #a1ajj #ccj #di ,jan4 #h #bb #e #a #a1ijj #ijj #dc ,jan4 #i #de #ac #a #ac1jjj #c1djj #ej ,jan4 #aj #gj #cj #a #aj1jjj #h1jjj #ej ,jan4 #aa #ef #bb #a #af1jjj #bbj #bjj ,jan4 #ab #dj #ab #a ,sunday4 ,jan4 #ac #aaj #ea #b #h1ejj #a1bjj #dc ,jan4 #ad #baj #aac #d #af1jjj #f1jjj #bhj ,jan4 #ae #cbe #bbb #ae #bd1jjj #i1ejj #gjj ,jan4 #af #cfj #bdg #db #bh1jjj #ad1jjj #ijj ,jan4 #ag #bdb #adg #bf #fe1jjj #bj1jjj #a1bjj ,jan4 #ah #acg #gc #g #g1jjj #f1ejj #djj ,jan4 #ai 444 444 444 ,sunday4 ,jan4 #bj,scraped4 ,jan4 #ba #ee #be #d 444 444 444 ,jan4 #bb #di #ba #d #c1fjj #a1ijj #aej ,jan4 #bc #dj #ae #c #a1hjj #gjj #agj ,jan4 #bd #dj #ac #c #b1cjj #iej #ij ,jan4 #be #ci #ab #c #a1ajj #hjj #ie ,jan4 #bf #cb #i #b ,sunday4 ,jan4 #bg #cb #i #b #cjj #gjj #gj ,jan4 #bh #de #ae #b #a1bjj #ijj #gj ,jan4 #bi #fj #bf #b #a1jjj #a1djj #ie ,jan4 #cj #eg #bg #b #a1djj #baj #cc ,jan4 #ca #db #ah #b #a1ajj #gej #de ---------------------------------------- ------------------ ,feb4 #a #ci #ad #b #gej #a1jjj #gj ,feb4 #b #bg #i #b ,sunday4 ,feb4 #c #bi #h #b #a1cjj #gej #bj ,feb4 #d #be #f #b #fjj #ijj #fj ,feb4 #e #bd #f #b #gej #bjj #ge ,feb4 #f #bj #e #b #b1jjj #hjj #fj ,feb4 #g #ag #d #a 444 #fjj #cd ,feb4 #h #ae #d #a #ijj #bbj #ce ,feb4 #i #ad #d #a ,sunday4 ,feb4 #aj #aa #d #a #hej #ejj #bh ,feb4 #aa #aj #d #a #a1jjj #ejj #bc ,feb4 #ab #h #d #a #gej #bij #ah ,feb4 #ac #i #d #a #gjj #bfj #aj ,feb4 #ad #i #d #a #a1bjj #bej #bg ,feb4 #ae #fa #ah #a #e1ejj #d1hjj #ac ,feb4 #af #hj #dj #b ,sunday4 ,feb4 #ag #hj #dj #c #cc1jjj #a1cjj #fj ,feb4 #ah #acj #fe #c 444 #iej #abj ,feb4 #ai #cbj #bjj #g #bh1jjj #bb1jjj #cfj ,feb4 #bj #agg #ig #i #bb1jjj #af1cjj #cej ,feb4 #ba #aje #eb #f #aj1fjj #c1hjj #bgj ,feb4 #bb #he #db #e ,holiday4 ,feb4 #bc #fj #cj #d ,sunday4 ,feb4 #bd #df #ai #c #c1fjj #a1gjj #abj ,feb4 #be #ca #i #b #b1cjj #a1cjj #fj ,feb4 #bf #cj #h #b #c1hjj #a1cjj #dc ,feb4 #bg #cj #g #a #a1cjj #ijj #db ,feb4 #bh #cg #g #a #a1djj #hjj #ca ,feb4 #bi #abc #di #b #ac1ejj #gej #ce ---------------------------------------- ------------------ ,mar4 #a #ig #dd #e ,sunday4 ,mar4 #b #hb #ce #d #h1jjj #b1ejj #gj ,mar4 #c #hg #ch #d #aa1jjj #f1jjj #ee ,mar4 #d #fg #bi #c #f1jjj #a1djj #ch ,mar4 #e #ei #bc #c #d1djj #b1ejj #cg ,mar4 #f ,discontinued2 sand filter being used for sedimentation experiments4 ,illustration3 ,figure #i--;,detail of ,strainer ,system4 ,table #ai--,record of ,experimental ,filter ,plant4 ,no4 #c4 ,sand ,filter4 ,turbidity4 ---------------------------------------- - ,date4 ,rate4 ,loss of,applied ,effluent1,effluent1 head4 water4coagulant4 sand4 ---------------------------------------- -------- #aijg4 ---------------------------------------- -------- ,feb4 #ab #b4ii #j4ah #ad 444 #b ,feb4 #ac #c4jj #j4ag #ae 444 #b ,feb4 #ad #c4ai #j4ah #ae 444 #b ,feb4 #ae #c4hf #j4bb #ab 444 #b ,feb4 #af #c4hd #j4bi #ad 444 #b ,feb4 #ag 444 444 444 444 444 ,feb4 #ah 444 444 444 444 444 ,feb4 #ba #c4ia #j4cb #bj 444 #b ,feb4 #bb #c4ie #j4ci #ae 444 #b ,feb4 #bc #c4id #j4dc #bj 444 #c ,feb4 #bd #c4hi #j4dg #bj 444 #c ,feb4 #be #d4ai #j4eb #bj 444 #c ,feb4 #bf #d4ac #j4eg #bj 444 #c ,feb4 #bg #c4cb #j4fb #ag 444 #c ,feb4 #bh #d4da #j4fg #ae 444 #c ---------------------------------------- -------- ,mar4 #a #c4ia #j4gb #ae 444 #c ,mar4 #b #c4ic #j4gi #ae 444 #c ,mar4 #c #c4ij #j4hb #ca 444 #c ,mar4 #d #c4ib #j4hj #ce 444 #c ,mar4 #e #c4if #j4ih #ace 444 #d ,mar4 #f #d4je #a4be #ace #bi #b ,mar4 #g #c4ie #a4eb #ajb #ae #a ,mar4 #h #c4ij #a4fg #ajj #ae #a ,mar4 #i #c4ic #a4hj #ij #ae #a ,mar4 #aj #c4ie #a4ia #hb #af #a ,mar4 #aa #c4if #b4jh #fh #ah #a ,mar4 #ab #d4jb #b4ai #df #ah #a ,mar4 #ac #d4jb #b4ca #dj #ae #a ,mar4 #ad #c4if #b4dd #ci #af #a ,mar4 #ae #d4jg #b4db #ce #bj #a ,mar4 #af #c4he #b4bj #fj #bi #a ,mar4 #ag #c4ie #b4ba #ace #be #a ,mar4 #ah #c4hh #b4hf #agj #be #a ,mar4 #ai #c4hb #c4ca #abe #ba #a ,mar4 #bj #c4gh #c4dg #ajb #bj #a ,mar4 #ba #c4ga #c4gj #abe #bj #a ,mar4 #bb #c4fd #c4ha #aij #be #a ,mar4 #bc #c4eh #c4ie #ahj #bf #a ,mar4 #bd #c4df #d4ah #adj #ai #a ,mar4 #be,scraped1 #a4jc in4 of sand removed4 ,mar4 #bg #d4jf #j4bb #dg #h #a ,mar4 #bh #d4jb #j4cg #ce 444 #j ,mar4 #bi #d4jb #j4df #bf 444 444 ,mar4 #cj,shut down to fill coagulant basin4 444 444 #be 444 444 ,mar4 #ca #d4jj #j4de #ba #ae #a ---------------------------------------- -------- ,apr4 #a #c4ci #j4db #bj #ae #a ,apr4 #b #c4jf #j4df #bd #ag #a ,apr4 #c #c4ja #j4di #bd #ag #a ,apr4 #d #b4ie #j4ej #bj #ae #a ,apr4 #e #b4ie #j4ea #bj #ac #a ,apr4 #f #b4if #j4di #bj #ab #a ,apr4 #g #b4ii #j4dh #bj #ab #a ,apr4 #h #c4ja #j4di #ah #ab #a ,apr4 #i #c4ja #j4ee #ah #ab #a ,apr4 #aj #c4jb #j4eg #cj #ae #j ,apr4 #aa #c4jd #j4fa #ff #af #j ,apr4 #ab #c4ji #j4gb #gb #ac #j ,apr4 #ac #c4jg #j4hh #hj #ai #j ,apr4 #ad #b4ih #a4jd #gg #ah #a ,apr4 #ae #b4ig #a4bj #fb #ah #a ,apr4 #af #c4ja #a4cb #dg #ag #a ,apr4 #ag #c4je #a4dd #ci #ai #j ,apr4 #ah #c4jd #a4da #cj #bj #a ,apr4 #ai #c4jd #a4ce #be #ah #a ,apr4 #bj #c4jg #a4cj #bj #ae #a ,apr4 #ba #c4jg #a4bf #bj #ae #a ,apr4 #bb #c4jd #a4ba #ah #ab #j ,apr4 #bc #c4jf #a4bb #ae #aj #j ,apr4 #bd #b4ii #a4bf #ai #aj #j ,apr4 #be #c4jd #a4bg #cd #ab #j ,apr4 #bf #c4jg #a4bh #df #ab #j ,apr4 #bg #b4id #a4di #eb 444 #j ,apr4 #bh #b4if #a4hh #de 444 #a ,apr4 #bi #b4ii #b4dj #dd #cc #a ,apr4 #cj #c4jj #b4hc #ci #bi #a ---------------------------------------- -------- ,may #a #c4ja #b4ga #ca #ba #a ,may #b #c4ja #b4ea #bd #ae #a ,may #c #c4jj #b4cf #ai #ab #a ,may #d #c4ja #b4bi #af #aj #j ,may #e #c4ja #b4be #ae #i #j ,may #f #c4jf #b4cb #ac #h #j ,may #g #b4if #b4df #ab #g #j ,may #h #c4jj #b4ea #aj #e #j ,may #i #c4jj #b4gg #aj #e #j ,may #aj #c4ja #b4hg #aj #e #j ,may #aa #b4ii #c4af #ab #f #j ,may #ab #c4jj #c4cd #ag #g #j ,may #ac #c4jj #c4dd #ce #i #j ,may #ad #c4ja #c4df #ci #ab #j ,may #ae #c4ja #c4ef #ag 444 #j ,may #af #b4ic #d4jg #bd 444 #j ,may #ag #c4ja #d4cd #ah 444 #j ,may #ah #b4ic #d4be #ae #h #j ,may #ai #b4ig #d4cf #ab #h #j ,may #bj #c4ja #d4fd #ab #h #j ,may #ba #b4ii #d4ee #af #h #j ,may #bb #c4ja #d4eg #bj #h #j ,may #bc #c4jj #d4ea #ae #h #j ,may #bd #b4ih #d4dd #ae #h #j ,may #be #c4jj #d4ch #ae #h #j ,may #bf #c4jj #d4ch #ah #h #j ,may #bg ,shut down to scrape sand filter2 #a4ji in4 of sand removed4 ,may #bh ,cleaning coagulant basin and treating coagulant basin with #a3b1jjj1jjj solution of copper sulphate4 ,may #bi #af 444 444 ,may #cj #c4jj #j4aa #ad #h #a ,may #ca #c4ja #j4aj #ag #h #a ---------------------------------------- -------- ,june #a #c4ja #j4ji #ae #h #a ,june #b #c4ja #j4aj #ag #h #a ,june #c #c4ja #j4aj #bd #aj #a ,june #d #c4jd #j4aa #cg #ac #a ,june #e #c4jj #j4aa #fe #bi #a ,june #f #c4jj #j4aa #gg #df #a ,june #g #b4ii #j4ab #fd #ba #a ,june #h #b4ih #j4ag #df #bb #a ,june #i #c4jj #j4ah #dd #cj #a ,june #aj #c4ja #j4ah #cf #bf #a ,june #aa #c4jj #j4ag #cj #bj #a ,june #ab #c4jj #j4ag #cd #bb #a ,june #ac #b4ii #j4ag #ce #be #a ,june #ad #b4ih #j4ag #ca #bb #a ,june #ae #b4ii #j4ai #cb #bb #a ,june #af #c4jb #j4ba #bf #ah #a ,june #ag #b4ii #j4bc #bf #af #a ,june #ah #c4jb #j4be #ca #bj #a ,june #ai #c4jb #j4bi #cg #bg #a ,june #bj #c4jj #j4cb #cj #ba #a ,june #ba #c4ja #j4cf #be #af #a ,june #bb #c4jj #j4dj #bj #ab #a ,june #bc #b4ig #j4dc #bf #aa #a ,june #bd #b4ig #j4dd #adj #cf #a ,june #be #c4jb #j4de #acj #bg #a ,june #bf ,interrupted1 defective meter4 ,june #bg #c4jj #j4dc #fe #ae #j ,june #bh #c4jj #j4dd #dg #ai #j ,june #bi #b4ii #j4dd #cg #bj #j ,june #cj #b4ig #j4db #cj #ai #j ---------------------------------------- -------- ,july #a #b4ii #j4cg #cj #ah #j ,july #b #c4ja #j4cc #cb #ai #j ,july #c #c4jj #j4ca #cf #ba #j ,july #d #c4jj #j4cj #dd #cj #j ,july #e #c4jj #j4bi #dd #ce #j ,july #f #c4jj #j4bh #ci #cj #j ,july #g #c4jj #j4bh #cd #bd #j ,july #h #c4jj #j4bh #be #af #j ,july #i #c4jj #j4bg #bb #ac #j ,july #aj #b4ih #j4bg #dg #bg #a ,july #aa #c4jj #j4bg #ij #da #a ,july #ab #c4jj #j4bi #ig #ba #a ,july #ac #c4jj #j4cd #ij #bj #j ,july #ad #c4jj #j4dj #ij #ai #j ,july #ae #c4jj #j4ed #ie #ah #j ,july #af #c4jj #j4ei #abj #bj #j ,july #ag #c4jj #j4eh #he #af #j ,july #ah #b4ii #j4fa #ef #ac #j ,july #ai #c4ja #j4fa #da #ah #j ,july #bj #b4ii #j4ea #fb #bg #j ,july #ba #c4jj #j4dg #fb #cb #j ,july #bb #c4jj #j4dg #hj #cd #j ,july #bc #c4ja #j4di #aje #ba #j ,july #bd #c4ja #j4fj #ie #ai #j ,july #be #c4jj #j4fh #gg #af #j ,july #bf #b4ii #j4fh #fg #ag #j ,july #bg #c4jj #j4fi #ed #bj #j ,july #bh #c4jj #j4gb #df #bg #j ,july #bi #c4jj #j4gd #cf #bf #j ,july #cj #b4ii #j4gf #bi #ai #j ,july #ca #b4ii #j4gg #ba #ab #j ---------------------------------------- -------- ,aug4 #a #c4jj #j4ge #af #i #j ,aug4 #b #c4jj #j4gd #ae #h #j ,aug4 #c #c4jj #j4gd #af #g #j ,aug4 #d #c4jj #j4ge #ba #f #j ,aug4 #e #c4jj #j4gf #bi #h #j ,aug4 #f #c4jj #j4gi #cd #ab #j ,aug4 #g #b4ii #a4ja #ba #ab #j ,aug4 #h #c4jj #a4ca #ai #aa #j ,aug4 #i #b4ih #a4dd #af #i #j ,aug4 #aj #c4jj #a4dd #bd #i #j ,aug4 #aa #c4jj #a4di #fb #bb #j ,aug4 #ab #c4jj #a4fb #abj #ci #j ,aug4 #ac #b4ig #b4jf #ajg #bb #j ,aug4 #ad #b4ig #c4jf #hb #ai #j ,aug4 #ae #b4ha #c4ia #fe #ae #j ,aug4 #af #c4jj #d4bi #de #ah #j ,aug4 #ag #c4jj #c4hf #ce #bb #j ,aug4 #ah #c4jj #c4dg #ba #ac #j ,aug4 #ai #c4jj #c4di #ah #aj #j ,aug4 #bj #c4jj #c4ef #bj #h #j ,aug4 #ba #c4jj #c4eh #bj #aj #j ,aug4 #bb #b4ii #c4gc #bg #ac #j ,aug4 #bc #c4jj #d4jj #di #cd #j ,aug4 #bd #c4jj #d4je #cf #bf #j ,aug4 #be #b4ih #d4jf #cd #bd #j ,aug4 #bf #c4jj #d4bj #ba #ac #j ,aug4 #bg #c4jj #d4ca #ai #aa #j ,aug4 #bh #b4ii #d4dj #ah #aj #j ,aug4 #bi #c4ja #d4da #ag #i #j ,aug4 #cj #b4ih #d4df #ae #h #j ,aug4 #ca ,scraped4 #ac 444 444 #a4hh in4 of sand removed4 ---------------------------------------- -------- ,sept4 #e #c4jj #j4aj #cd #d #j ,sept4 #f #c4jj #j4aj #afj #c #j ,sept4 #g #c4jj #j4ji #fd #c #j ,sept4 #h #c4jj #j4jh #ef #d #j ,sept4 #i #c4jj #j4jh #ei #c #j ,sept4 #aj #b4ig #j4jg #eg #c #j ,sept4 #aa #b4ih #j4jg #fe #b #j ,sept4 #ab #b4ih #j4jh #gb #b #j ,sept4 #ac #c4jj #j4jh #hg #c #j ,sept4 #ad #c4jj #j4jh #gb #c #j ,sept4 #ae #c4jj #j4jh #fe #c #j ,sept4 #af #c4jj #j4jh #fe #b #j ,sept4 #ag #c4jj #j4jh #eb #b #j ,sept4 #ah #c4jj #j4jh #fj #b #j ,sept4 #ai #b4ih #j4jh #he #b #j ,sept4 #bj #b4ih #j4ji #ajj #b #j ,sept4 #ba #b4ii #j4ji #abj #c #j ,sept4 #bb #c4jj #j4ji #acg #c #j ,sept4 #bc #c4jb #j4ji #aab #d #j ,sept4 #bd #c4jj #j4aj #ajj #d #j ,sept4 #be #c4jj #j4aa #dcb #c #j ,sept4 #bf #b4ii #j4aa #che #b #j ,sept4 #bg #c4jj #j4ab #bde #d #j ,sept4 #bh #b4ih #j4ac #abg #d #j ,sept4 #bi #b4ih #j4ad #aje #d #j ,sept4 #cj #b4ii #j4ae #aae #c #j ---------------------------------------- -------- ,oct4 #a #c4jj #j4ae #hb #c #j ,oct4 #b #b4ih #j4af #fe #c #j ,oct4 #c #c4jj #j4ag #ei #b #j ,oct4 #d #b4ii #j4ag #ee #b #j ,oct4 #e #b4ii #j4ai #ei #b #j ,oct4 #f #b4ih #j4bj #ei #b #j ,oct4 #g #b4ih #j4ba #eb #b #j ,oct4 #h #b4ig #j4ba #ed #b #j ,oct4 #i #b4ih #j4bb #ea #b #j ,oct4 #aj #b4ih #j4bd #ej #b #j ,oct4 #aa #b4ih #j4be #dg #b #j ,oct4 #ab #b4ig #j4bf #cf #c #j ,oct4 #ac #b4ih #j4bg #dj #d #j ,oct4 #ad #b4ih #j4bi #dg #e #j ,oct4 #ae #b4ii #j4ca #da #e #j ,oct4 #af #b4ii #j4cb #ce #d #j ,oct4 #ag #b4ih #j4cd #cj #d #j ,oct4 #ah #c4jj #j4ce #be #d #j ,oct4 #ai #c4jj #j4ce #be #d #j ,oct4 #bj #c4jj #j4ce #bj #c #j ,oct4 #ba #c4jj #j4ce #ai #c #j ,oct4 #bb #b4ii #j4cf #ah #c #j ,oct4 #bc #b4ii #j4cg #ae #c #j ,oct4 #bd #b4ih #j4ch #ae #c #j ,oct4 #be #b4ii #j4ci #ae #c #j ,oct4 #bf #b4ii #j4dj #ae #c #j ,oct4 #bg #b4ii #j4da #ac #b #j ,oct4 #bh #b4ii #j4dc #ac #b #j ,oct4 #bi #b4ih #j4dd #be #b #j ,oct4 #cj #b4ii #j4df #ba #b #j ,oct4 #ca #b4if #j4dh #be #c #j ---------------------------------------- -------- ,nov4 #d #c4jj #j4ea #abe #b #j ,nov4 #e #c4jj #j4ec #ahe #b #j ,nov4 #f #b4ii #j4ef #agj #b #j ,nov4 #g #b4ii #j4fj #ajj #c #j ,nov4 #h #b4ii #j4fd #ie #c #j ,nov4 #i #b4ii #j4gj #hj #d #j ,nov4 #aj #b4ii #j4gi #fg #d #j ,nov4 #aa #b4ii #a4jj #eb #f #j ,nov4 #ab #b4ii #a4df #dj #i #j ,nov4 #ac #b4ih #b4ji #cf #aj #j ,nov4 #ad #b4ii #b4gd #db #i #j ,nov4 #ae #b4ii #b4ih #ce #h #j ,nov4 #af #b4ii #c4jc #bf #h #j ,nov4 #ag #c4jj #c4jg #bj #f #j ,nov4 #ah #c4jj #c4ji #ag #e #j ,nov4 #bj #b4ii #c4ag #de #c #j ,nov4 #ba #b4ii #c4bb #eb #c #j ,nov4 #bb #b4ii #c4bg #fe #e #j ,nov4 #bc #b4ii #c4cc #di #h #j ,nov4 #bd #b4ii #c4da #acd #aa #j ,nov4 #be #b4ih #c4ed #bbe #ab #a ,nov4 #bf #b4ih #c4fh #bcg #ac #a ,nov4 #bg #b4ii #c4if #ahe #af #a ,nov4 #bh #b4ih #d4bi #acj #ah #a ,nov4 #bi #b4ig #d4dh #hj #ai #a ,nov4 #cj #b4ig #d4ed #ed #ae #a ---------------------------------------- -------- ,dec4 #f ,scraped1 #a4fb in4 of sand removed4 ,dec4 #h #b4ig #j4af #ab #c #j ,dec4 #i #b4ih #j4af #aa #c #j ,dec4 #aj #b4ih #j4ae #ab #c #j ,dec4 #aa #b4ii #j4ae #bee #c #j ,dec4 #ab #c4jj #j4ac #bab #b #j ,dec4 #ac #b4ih #j4ac #die #d #j ,dec4 #ad #b4ii #j4ad #ceg #e #j ,dec4 #ae #b4ii #j4ae #aeg #f #j ,dec4 #af #b4ih #j4af #ij #i #j ,dec4 #ag #b4ih #j4bj #gj #ab #j ,dec4 #ah #b4ih #j4bd #di #ab #a ,dec4 #ai #b4ih #j4bi #ci #i #a ,dec4 #bj #b4ih #j4cf #db #g #a ,dec4 #ba #b4ig #j4de #bf #e #j ,dec4 #bb #b4ih #j4eg #bj #d #j ,dec4 #bc #b4ih #j4ga #cd #c #j ,dec4 #bd #b4ih #j4hc #aie #b #j ,dec4 #be #b4ih #j4ig #dde #b #j ,dec4 #bf #b4ih #a4aa #cgj #b #j ,dec4 #bg #b4ih #a4bg #bde #c #j ,dec4 #bh #b4ih #a4dj #ajb #d #j ,dec4 #bi #b4ih #a4fj #ge #c #j ,dec4 #cj #b4ig #a4he #ef #c #j ,dec4 #ca #b4ih #b4jg #ci #b #j ---------------------------------------- -------- #aijh4 ---------------------------------------- -------- ,jan4 #a #b4ii #b4aa #ca #b #j ,jan4 #b #b4ih #b4ag #ci #b #j ,jan4 #c #b4ih #b4bf #cf #b #j ,jan4 #d #b4ih #b4cd #cb #b #j ,jan4 #e #b4ih #b4da #bf #b #j ,jan4 #f #b4ih #b4di #bj #b #j ,jan4 #g #b4ih #b4eh #bj #b #j ,jan4 #h #b4ii #b4fa #bb #b #j ,jan4 #i #b4ii #b4fc #de #b #j ,jan4 #aj #b4ih #b4fg #gj #b #j ,jan4 #aa #b4ih #b4gb #ef #b #j ,jan4 #ab #b4ih #b4gh #dj #b #j ,jan4 #ac #b4ih #b4hd #aaj #b #j ,jan4 #ad #b4ih #b4ie #baj #b #j ,jan4 #ae #b4ih #c4jg #cbe #c #j ,jan4 #af #b4ih #c4bc #cfj #e #f ,jan4 #ag #b4ig #c4gc #bdb #f #j ,jan4 #ah #b4ih #d4db #acg #f #j ,jan4 #ai #b4ii #d4ge #aag #e #j ,jan4 #ba ,scrape1 #a4de in4 of sand removed4 ,jan4 #bc #c4jj #j4ad #dj #c #j ,jan4 #bd #c4jj #j4ad #dj #c #j ,jan4 #be #c4jj #j4ac #ci #c #j ,jan4 #bf #c4jj #j4ac #cb #c #j ,jan4 #bg #c4jj #j4ac #cb #b #j ,jan4 #bh #b4ii #j4ae #de #c #j ,jan4 #bi #b4ii #j4bj #fi #f #a ,jan4 #cj #b4ii #j4bd #eg #h #a ,jan4 #ca #b4ii #j4cj #db #f #a ---------------------------------------- -------- ,feb4 #a #b4ii #j4cd #ci #e #a ,feb4 #b #b4ii #j4da #bg #d #a ,feb4 #c #b4ii #j4ea #bi #c #j ,feb4 #d #b4ii #j4ef #be #c #j ,feb4 #e #b4ii #j4eh #bd #d #j ,feb4 #f #b4ii #j4fa #bj #f #j ,feb4 #g #c4jj #j4fd #ag #h #a ,feb4 #h #b4ii #j4ff #ae #h #a ,feb4 #i #c4jj #j4fg #ad #h #a ,feb4 #aj #b4ii #j4fg #aa #h #a ,feb4 #aa #c4jj #j4ff #aj #g #a ,feb4 #ab #c4ja #j4fd #h #f #a ,feb4 #ac #c4jj #j4fb #i #e #a ,feb4 #ad #c4jj #j4fa #i #e #a ,feb4 #ae #c4jj #j4fj #fa #e #a ,feb4 #af #c4jj #j4fj #hj #f #a ,feb4 #ag #c4jj #j4fb #hj #ad #a ,feb4 #ah #b4ii #j4fg #acj #bj #a ,feb4 #ai #b4ii #j4gf #cbj #ah #b ,feb4 #bj #b4ii #j4hc #agg #ae #b ,feb4 #bi #c4jj #j4he #abc #h #a ---------------------------------------- -------- ,mar4 #a #c4jj #j4hg #ig #i #a ,mar4 #b #b4ii #j4ib #hb #ac #a ,mar4 #c #b4ih #j4if #hg #ai #a ,mar4 #d #b4ii #a4jb #fg #ba #a ,mar4 #e #b4ii #a4jh #ei #be #a ,mar4 #f #b4ii #a4ae #gb #be #b ,mar4 #g #b4ih #a4ba #hb #be #b ,mar4 #h #b4ii #a4be #ib #bi #b ,mar4 #i #b4ii #a4cj #abe #cd #b ,mar4 #aj #b4ii #a4ce #adb #ci #b ,mar4 #aa #b4ii #a4ci #aee #ce #b ,mar4 #ab #b4ii #a4db #ace #bi #b ,mar4 #ac #b4ii #a4df #abb #ai #b ,mar4 #ad #b4ii #a4dg #ig #ab #a ,mar4 #ae #b4ii #a4dh #gg #h #a ,mar4 #af #c4jj #a4eb #fe #i #j ,mar4 #ag #b4ii #a4ff #ei #g #j ,mar4 #ah #b4ii #a4gb #fg #aa #a ,mar4 #ai #b4ii #a4ge #fj #bd #a ,mar4 #bj #b4ii #a4ha #eg #be #a ,mar4 #ba #b4ii #a4hi #fg #bb #a ,mar4 #bb #b4ii #a4ie #hj #ba #a ,mar4 #bc #c4jj #b4jj #ij #bf #a ,mar4 #bd #b4ih #b4jf #hb #cb #a ,mar4 #be #b4ii #b4ag #fg #ci #a ,mar4 #bf #b4ii #b4bd #fj #cf #a ,mar4 #bg #b4ii #b4bi #ei #cj #a ,mar4 #bh #c4jj #b4cb #ea #ba #a ,mar4 #bi #b4ii #b4ce #ca #ah #a ,mar4 #cj #c4jj #b4ch #cj #ad #a ,mar4 #ca #b4ii #b4dc #ci #i #a ---------------------------------------- -------- ,apr4 #a #b4ii #b4ej #dd #g #a ,apr4 #b #b4ii #b4eh #db #h #a ,apr4 #c #b4ii #b4fe #da #aa #a ,apr4 #d #b4ii #b4gd #ed #ab #a ,apr4 #e #c4jj #b4hb #ej #ab #a ,apr4 #f #b4ii #b4hh #da #ad #a ,apr4 #g #b4ii #b4ih #ce #ac #a ,apr4 #h #b4ih #c4ae #ci #aa #a ,apr4 #i #b4ii #c4ce #dj #h #a ,apr4 #aj #b4ih #c4ej #dj #h #a ,apr4 #aa #b4ii #c4fe #de #g #j ,apr4 #ab #b4ii #c4gi #eb #e #j ,apr4 #ac #b4ii #c4ib #ej #d #j ,apr4 #ad #b4ii #d4je #de #d #j ,apr4 #ae #b4ii #d4af #de #c #j ,apr4 #af 444 #d4bd #de #c #j ,apr4 #ba ,scraped1 #j4ab in4 of sand removed4 ,apr4 #bc 444 #j4ac #be #b #j ,apr4 #bd #c4jj #j4ab #ba #b #j ,apr4 #be #c4jj #j4aj #bj #b #j ,apr4 #bf #c4jj #j4aj #ba #c #j ,apr4 #bg #c4jj #j4aj #ah #c #j ,apr4 #bh #c4jj #j4aj #bj #c #j ,apr4 #bi #c4jj #j4ji #bd #c #j ,apr4 #cj #c4jj #j4ji #ba #c #j ---------------------------------------- -------- ,may #a #c4jj #j4ji #cb #c #j ,may #b #c4jj #j4ji #bf #c #j ,may #c #c4jj #j4aa #bb #e #j ,may #d #c4jj #j4aa #ai #d #j ,may #e #c4jj #j4aa #ah #d #j ,may #f #b4ii #j4ab #ah #c #j ,may #g #c4jj #j4ac #ai #c #j ,may #h #c4jj #j4ad #ai #c #j ,may #i #b4ii #j4ad #ah #c #j ,may #aj #c4jj #j4ad #cj #c #j ,may #aa #c4jj #j4ac #fj #c #j ,may #ab #c4jj #j4ac #gj #c #j ,may #ac #c4jj #j4ac #ff #g #j ,may #ad #c4jj #j4ad #de #i #j ,may #ae #b4ii #j4ad #ci #g #j ,may #af #b4ii #j4bb #di #f #j ,may #ag #b4ii #j4cc #df #d #j ,may #ah #b4ii #j4dd #ca #c #j ,may #ai #b4ih #j4fb #cf #c #j ,may #bj #b4ii #j4ge #da #c #j ,may #ba #b4ii #j4hi #ca #d #j ,may #bb #b4ii #a4ja #ej #e #j ,may #bc #b4ii #a4ab #abg #e #j ,may #bd #b4ii #a4bj #aaj #f #j ,may #be #b4ii #a4bd #ij #i #j ,may #bf #b4ih #a4ca #ace #aa #j ,may #bg #b4ig #a4ed #aaj #ab #j ,may #bh #b4ig #a4ha #ij #aj #j ,may #bi #b4ig #b4jh #gj #g #j ,may #cj #b4ig #b4cf #ej #e #j ,may #ca #b4ih #b4fc #cd #d #j ---------------------------------------- -------- ,june #a #b4ih #b4gg #ce #b #j ,june #b #b4ih #b4hd #ci #b #j ,june #c #b4ih #c4jb #ce #c #j ,june #d #c4jj #c4ja #cj #d #j ,june #e #c4jj #b4ig #cj #e #j ,june #f #c4ja #b4ha #bg #e #j ,june #g #c4ja #b4fb #bb #e #j ,june #h #c4ja #b4ch #bj #d #j ,june #i #c4jj #b4ai #bj #c #j ,june #aj #c4ja #b4jb #ag #c #j ,june #aa #b4ii #a4hi #ab #c #j ,june #ab #b4ih #a4ib #aa #b #j ,june #ac #b4ih #a4ii #cf #b #j ,june #ad #b4ih #b4jh #ci #b #j ,june #ae #b4ih #b4be #be #d #j ,june #af #b4ih #b4ed #cd #e #j ,june #ag #b4ig #b4he #fd #e #j ,june #ah #b4ig #c4bj #eg #e #j ,june #ai #b4ih #c4dg #df #g #j ,june #bj #b4ii #c4gc #cg #h #j ,june #ba #b4ii #d4aj #bi #h #j ,june #bb #b4ii #d4dd #be #f #j ,june #bc #b4ii #d4fa #be #e #j ,june #bf #c4ja #j4ji #ae #b #j ,june #bg #c4jj #j4ji #ab #b #j ,june #bh #c4jj #j4ji #i #b #j ,june #bi #c4jj #j4jh #h #b #j ,june #cj #c4jj #j4jg #aj #b #j ---------------------------------------- -------- ,july #a #c4jj #j4jg #f #b #j ,july #b #c4jj #j4jg #h #b #j ,july #c #c4jj #j4jg #h #b #j ,july #d #c4jj #j4jg #i #b #j ,july #e #c4jj #j4jg #aj #b #j ,july #f #c4jj #j4jg #i #b #j ,july #g #c4jj #j4jg #h #b #j ,july #h #c4jj #j4jg #i #b #j ,july #i #c4jj #j4jg #h #b #j ,july #aj 444 444 444 444 444 ,july #aa #c4jj #j4jh #ab #b #j ,july #ab #c4jj #j4jh #aa #b #j ,july #ac #c4jj #j4jh #aj #b #j ,july #ad #c4jj #j4ji #af #b #j ,july #ae #c4jj #j4ji #ag #b #j ,july #af #c4jj #j4aj #ad #b #f ,july #ag #c4jj #j4aj #aj #b #j ,july #ah #c4jj #j4aa #aa #b #j ,july #ai #c4jj #j4aa #ab #b #j ,july #bj #c4jj #j4ab #aj #b #j ,july #ba #c4jj #j4ab #aj #b #j ,july #bb #c4jj #j4ac #ac #b #j ,july #bc #b4ii #j4ac #ed #b #j ,july #bd #b4ii #j4ad #cje #b #j ,july #be #c4jj #j4ae #ccj #d #j ,july #bf #c4jj #j4ae #bij #i #j ,july #bg #c4jj #j4af #cce #aa #j ,july #bh #b4ii #j4ag #agj #aj #j ,july #bi #c4jj #j4ag #ahj #h #j ,july #cj #b4ii #j4ah #bcg #g #j ,july #ca #c4jj #j4ai #bej #f #j ,table #ai--7;,continued47 ,bacteria4 ,coagulant4 ---------------------------------------- ,date4 ,applied ,effluent1,effluent1,grains1 per water4 coagulant4 sand4 gallon4 ---------------------------------------- -------- #aijg4 ---------------------------------------- -------- ,feb4 #ab 444 444 444 444 ,feb4 #ac #fjj 444 444 444 ,feb4 #ad #fej 444 444 444 ,feb4 #ae #fjj 444 #b1ejj 444 ,feb4 #af #hej 444 #a1fjj 444 ,feb4 #ag 444 444 444 444 ,feb4 #ah #a1bjj 444 #cjj 444 ,feb4 #ba #a1hjj 444 #eej 444 ,feb4 #bb #b ,holiday4 ,feb4 #bc #a1fjj 444 #a1ajj 444 ,feb4 #bd #c ,sunday4 ,feb4 #be #a1djj 444 #fjj 444 ,feb4 #bf #gjj 444 #fej 444 ,feb4 #bg #gjj 444 #b1cjj 444 ,feb4 #bh #hjj 444 #eej 444 ---------------------------------------- -------- ,mar4 #a #fej 444 #cjj 444 ,mar4 #b #a1jjj 444 #bgj 444 ,mar4 #c ,sunday4 ,mar4 #d #a1bjj 444 #adj #a4de ,mar4 #e #ac1jjj 444 #aij #a4id ,mar4 #f #ah1jjj #b1ajj #afj #b4jc ,mar4 #g #bd1jjj #c1ejj #afj #a4ej ,mar4 #h #bb1jjj #a1hjj #acj #a4ch ,mar4 #i #bd1jjj #c1ejj #acj #a4cg ,mar4 #aj ,sunday4 #a4bf ,mar4 #aa #ah1jjj #f1jjj #abj #a4bd ,mar4 #ab #aa1jjj #i1jjj #adj #a4jh ,mar4 #ac #i1jjj #e1jjj #abj #j4id ,mar4 #ad #e1ejj #c1fjj #ij #j ,mar4 #ae #f1ejj #c1hjj #he #j ,mar4 #af #e1jjj #c1ejj #ajj #a4bf ,mar4 #ag ,sunday4 #a4eb ,mar4 #ah #i1jjj #a1ijj #he #a4ge ,mar4 #ai #g1jjj #gjj #fe #a4eg ,mar4 #bj #d1hjj #a1ejj #fj #a4ca ,mar4 #ba #h1ejj #a1ejj #gj #a4ch ,mar4 #bb #g1ejj #a1ajj #ce #a4eg ,mar4 #bc #g1ejj #dgj #ee #a4fh ,mar4 #bd ,sunday4 #a4eb ,mar4 #be,scraped1 #a4jc in4 of sand removed4 ,mar4 #bg #b1bjj #dhj #fj #a4jh ,mar4 #bh #a1cjj #bej #hj #a4jj ,mar4 #bi #gjj #bdj #fe #j ,mar4 #cj,shut down to fill coagulant basin4 #caj 444 444 #j ,mar4 #ca ,sunday4 #j ---------------------------------------- -------- ,apr4 #a #fjj #a1jjj #dc #j ,apr4 #b #bgj ,lost4 #ce #j ,apr4 #c #dfj ,apr4 #da #j ,apr4 #d #bhj #eej #bg #j ,apr4 #e #dej #a1jjj #fj #j ,apr4 #f #cbj #ej #ce #j ,apr4 #g ,sunday4 #j ,apr4 #h #ccj #fej #bb #j ,apr4 #i #adj #gej #ba #j ,apr4 #aj #gej #e1jjj #bi #j ,apr4 #aa #d1jjj #eej #be #a4aa ,apr4 #ab #ad1jjj #b1bjj #ag #a4ae ,apr4 #ac #ac1jjj #c1ijj #be #a4ad ,apr4 #ad ,sunday4 #a4ag ,apr4 #ae #g1jfj #b1bjj #ai #a4ji ,apr4 #af #c1fjj #ijj #bb #a4jh ,apr4 #ag #a1fjj #a1ajj #ab #j ,apr4 #ah #a1haj #a1hgj #ad #j ,apr4 #ai #gij #iaj #ad #j ,apr4 #bj #edj #dhj #ae #j ,apr4 #ba ,sunday4 444 ,apr4 #bb #bce #dbj #ba #j ,apr4 #bc #agj #dbj #h #j ,apr4 #bd #aej #bej #ag #j ,apr4 #be #gjj #bfj #ai #j ,apr4 #bf #a1bjj #cbj #hj #j ,apr4 #bg #a1gjj #a1ejj #gj #j ,apr4 #bh ,sunday4 #j ,apr4 #bi #fjj #a1djj #ai #j ,apr4 #cj #eej #a1bjj #ad #j ---------------------------------------- -------- ,may #a #ejj #a1cjj #bj #j ,may #b #ejj #hej #af #j ,may #c #bhj #fej #cd #j ,may #d #djj #eej #bd #j ,may #e ,sunday4 #j ,may #f #cij #dfj #hj #j ,may #g #aij 444 #ah #j ,may #h 444 444 444 #j ,may #i #cij #a1ajj #ad #j ,may #aj #cjj #ejj #ba #j ,may #aa #cij #fej #af #j ,may #ab ,sunday4 #j ,may #ac #fjj #dgj #bg #j ,may #ad #ejj #eej #be #j ,may #ae #ejj #ijj #bc #j ,may #af #bij #b1ejj #be #j ,may #ag #bfj #b1jjj #af #j ,may #ah #aij #fjj #ai #j ,may #ai ,sunday4 #j ,may #bj #bfj #dej #ae #j ,may #ba #bfj #ccj #ad #j ,may #bb #bhj #cij #bb #j ,may #bc #acj #bdj #ai #j ,may #bd #agj #bdj #cj #j ,may #be #cdj #djj #da #j ,may #bf ,sunday4 #j ,may #bg ,shut down to scrape sand filter2 #a4ji in4 of sand removed4 ,cleaning ,may #bh coagulant basin and treating coagulant basin with #a3b1jjj1jjj ,may #bi solution of copper sulphate4 ,may #cj ,holiday4 #j ,may #ca #chj #ah1jjj #aej #j ---------------------------------------- -------- ,june #a #ijj #g1jjj #aej #j ,june #b ,sunday4 #j ,june #c #eej #h1jjj #acj #j ,june #d #f1ejj #g1ejj #adj #j ,june #e #c1bjj #c1fjj #aaj #j ,june #f #a1ejj #hjj #fj #a4ag ,june #g #b1ajj #a1ejj #ij #a4ah ,june #h #ffj #a1jjj #fj #j ,june #i ,sunday4 #j ,june #aj #bdj #djj #cb #j ,june #aa #bhj #cjj #ca #j ,june #ab #ccj 444 #bh #j ,june #ac #dhj #dhj #ci #j ,june #ad #ddj #eej #cb #j ,june #ae #dbj #dej #bg #j ,june #af ,sunday4 #j ,june #ag #cdj #gej #ad #j ,june #ah #ddj #gej #ba #j ,june #ai #ejj #dfj #ce #j ,june #bj #ccj #ddj #hh #j ,june #ba #agj #cgj #bc #j ,june #bb #ajj #cjj #ag #j ,june #bc ,sunday4 #j ,june #bd #a1gjj #cej #bb #a4ei ,june #be #djj #bej #af #a4ee ,june #bf #gej #ccj 444 #j ,june #bg 444 #a1djj 444 #j ,june #bh 444 #a1djj #abj #j ,june #bi #bbj #cjj 444 #j ,june #cj ,sunday4 #j ---------------------------------------- -------- ,july #a #djj #fjj #he #j ,july #b #ahj #a1jjj #ej #j ,july #c #cej #caj #ba #j ,july #d ,holiday4 ,july #e #eej #djj #da #j ,july #f #bej #bhj #bb #j ,july #g ,sunday4 #j ,july #h #bbj #bfj #bg #j ,july #i #ej #dj #ai #j ,july #aj ,lost4 ,lost4 ,lost4 #j ,july #aa #aej #ej #h #a4bg ,july #ab #cjj #bjj #ac #a4bg ,july #ac #bbj #afj #ag #a4bg ,july #ad ,sunday4 #a4bg ,july #ae #cge #aej #a4bg ,july #af ,lost4 #ej ,lost4 #a4cf ,july #ag #bgj #fj #c #a4bf ,july #ah #a1fge #gj #a4ag ,july #ai #dej #gjj #aa #j ,july #bj #cjj #gbj #h #j ,july #ba ,sunday4 #j ,july #bb #a1djj #efj #ad #a4ag ,july #bc #c1gjj #dij #dj #a4be ,july #bd #ggj #aaj #hj #a4bg ,july #be #bej #hj #e #a4bb ,july #bf #adj #dj #d #j ,july #bg #cjj #acj #ba #j ,july #bh ,sunday4 #j ,july #bi #dgj #bij #ajj #j ,july #cj ,lost4 ,lost4 ,lost4 #j ,july #ca ,july ,july ,july #j ---------------------------------------- -------- ,aug4 #a ,lost4 ,lost4 ,lost4 #j ,aug4 #b #acj #adj #d #j ,aug4 #c #abj #ahj #f #j ,aug4 #d ,sunday4 ,aug4 #e #bcj #ajj #dd #j ,aug4 #f #he #dgj 444 #j ,aug4 #g #bjj #dej 444 #j ,aug4 #h #ajj #ahj #de #j ,aug4 #i #ge #hj #af #j ,aug4 #aj #fj #ij #aa #j ,aug4 #aa ,sunday4 ,aug4 #ab #fbj #bfj #af #a4de ,aug4 #ac #hbj #ebj #aj #a4ch ,aug4 #ad #hej #abj #bf #a4bb ,aug4 #ae #aej #bfj #f #a4ag ,aug4 #af #bgj #cdj #ag #j ,aug4 #ag #cdj #bjj #ac #j ,aug4 #ah ,sunday4 ,aug4 #ai #ahj #bbj #ag #j ,aug4 #bj #baj #ahj #af #j ,aug4 #ba #a1cjj #fej #h #j ,aug4 #bb #c1hjj #cfj #f #j ,aug4 #bc #b1ejj #gjj #aj #j ,aug4 #bd #c1ijj #fcj #ab #j ,aug4 #be ,sunday4 ,aug4 #bf #gjj #caj #af #j ,aug4 #bg #dgj #bej #ab #j ,aug4 #bh #ejj #afj #ah #j ,aug4 #bi #cfj #aaj #i #j ,aug4 #cj #cbj #caj #ad #j ,aug4 #ca #bjj #ajj 444 #j ---------------------------------------- -------- ,sept4 #e #cfj #iej 444 #a4jd ,sept4 #f #ae1jjj #a1ejj #aij #a4ce ,sept4 #g #b1jjj #bfj #ajj #a4bj ,sept4 #h ,sunday4 444 #a4jd ,sept4 #i #bbj #ahj #ch #a4jd ,sept4 #aj #ah1jjj #aej #bi #a4jf ,sept4 #aa #b1gjj #bjj #cg #a4jd ,sept4 #ab #a1jjj #abe #ai #a4jd ,sept4 #ac #b1cjj #bjj #gb #a4bj ,sept4 #ad #b1djj #cfj #cf #a4ab ,sept4 #ae ,sunday4 #a4jd ,sept4 #af ,lost4 ,lost4 #ch #a4jd ,sept4 #ag #dbj #bjj #ch #a4jg ,sept4 #ah #ijj #bjj #ag #a4jg ,sept4 #ai #b1jjj #bbj #be #a4ab ,sept4 #bj #d1bjj #cbj #ca #a4bd ,sept4 #ba #a1ajj #afj #ai #a4cc ,sept4 #bb ,sunday4 #a4de ,sept4 #bc #b1ajj #aij #ae #a4da ,sept4 #bd #d1jjj #fbj #ac #a4cc ,sept4 #be #ef1jjj #bij #g #a4hc ,sept4 #bf #a1cjj #iej #ai #b4cd ,sept4 #bg #d1jjj ,lost4 #bj #a4ia ,sept4 #bh #ae1jjj #a1jjj #h #a4ed ,sept4 #bi ,sunday4 #a4cd ,sept4 #cj ,lost4 ,lost4 #df #a4ce ---------------------------------------- -------- ,oct4 #a #fjj #a1gjj #bb #a4bd ,oct4 #b #d1djj #eej #h #a4ji ,oct4 #c #ijj #ccj #ae #a4jd ,oct4 #d #hej #bej #aa #a4jc ,oct4 #e #b1jjj #dej #be #a4jd ,oct4 #f ,sunday4 #a4jd ,oct4 #g #a1bej #b1cjj #db #a4jd ,oct4 #h #aa1jjj #ajj #ae #a4jd ,oct4 #i #b1jjj #a1fjj #g #a4jd ,oct4 #aj #hjj ,lost4 #bd #a4jd ,oct4 #aa #b1jjj #a1bjj #ba #j ,oct4 #ab #a1bjj #a1bjj #ai #j ,oct4 #ac ,sunday4 #j ,oct4 #ad #a1bjj #hcj #be #j ,oct4 #ae #ijj ,lost4 #aje #j ,oct4 #af ,lost4 #eej #ai #j ,oct4 #ag #eej #hjj #ba #j ,oct4 #ah #bfj #cej #i #j ,oct4 #ai #gej #caj #ce #j ,oct4 #bj ,sunday4 #j ,oct4 #ba #dhj #edj #ce #j ,oct4 #bb #bcj #ddj #ag #j ,oct4 #bc #bej #ddj #ci #j ,oct4 #bd #cjj #ejj #fj #j ,oct4 #be #dej #daj #fe #j ,oct4 #bf #dej #ejj #dd #j ,oct4 #bg ,sunday4 #j ,oct4 #bh #aij #ejj #ej #j ,oct4 #bi #chj #fj #ge #j ,oct4 #cj #dej #ahj #c #j ,oct4 #ca #b1cjj #cij #ge #j ---------------------------------------- -------- ,nov4 #d 444 444 444 #j ,nov4 #e #f1jjj #a1fjj #ij #a4gj ,nov4 #f #e1jjj #c1ijj #f #a4gj ,nov4 #g #ad1jjj #cjj #i #a4dh ,nov4 #h #a1ijj #bcj #b #a4bg ,nov4 #i #d1jjj #b1gjj #bjj #j ,nov4 #aj ,sunday4 #j ,nov4 #aa #a1ijj #b1jjj #bjj #j ,nov4 #ab #g1ejj #b1cjj #afj #j ,nov4 #ac #a1fjj #a1ajj #agj #j ,nov4 #ad #b1gjj #iej #acj #j ,nov4 #ae #a1hjj #hjj #aa #j ,nov4 #af #a1ajj #hjj #ij #j ,nov4 #ag ,sunday4 #j ,nov4 #ah #a1fjj #gjj #ajj #j ,nov4 #bj #f1ejj #abj #abj #j ,nov4 #ba #i1ijj #a1jjj #hj #j ,nov4 #bb #aj1jjj #c1 #bjj #ij #j ,nov4 #bc #ah1jjj #b1 #djj #ajj #j ,nov4 #bd ,sunday4 #j ,nov4 #be #ej1jjj #b1 #ajj #fe #a4fh ,nov4 #bf #dj1jjj #b1 #djj #ie #a4gf ,nov4 #bg #af1jjj #b1 #fjj #fj #a4gd ,nov4 #bh ,holiday4 #a4eg ,nov4 #bi #aj1jjj #b1 #ejj #fe #a4ej ,nov4 #cj #c1hjj #a1 #ijj #he #j ---------------------------------------- -------- ,dec4 #f ,scraped1 #a4fb in4 of sand removed4 ,dec4 #h ,sunday4 #a4ag ,dec4 #i #a1bjj #daj #aj #a4ag ,dec4 #aj #hjj #eej #aej #a4ag ,dec4 #aa #f1ejj #fjj #acj #a4eb ,dec4 #ab #dh1jjj #ejj #acj #a4ii ,dec4 #ac #db1jjj #ejj #abj #b4jf ,dec4 #ad #di1jjj #gej #aej #b4ab ,dec4 #ae ,sunday4 #a4fi ,dec4 #af #ai1jjj #ijj #bj #a4bh ,dec4 #ag #ba1jjj #djj #agj #a4ag ,dec4 #ah #f1ejj #g1jjj #cej #a4ag ,dec4 #ai ,lost4 ,lost4 ,lost4 #a4ag ,dec4 #bj ,dec4 ,dec4 ,dec4 #a4ag ,dec4 #ba ,dec4 ,dec4 ,dec4 #a4ag ,dec4 #bb ,sunday4 #a4ag ,dec4 #bc #a1djj #a1cjj #bbj #a4ag ,dec4 #bd #i1jjj #a1jjj #adj #a4di ,dec4 #be ,holiday4 #b4dc ,dec4 #bf #ea1jjj #a1jjj #ci #b4ae ,dec4 #bg #ee1jjj #a1fjj #gj #a4ia ,dec4 #bh #aj1jjj #a1jjj #hj #a4ej ,dec4 #bi ,sunday4 #a4ba ,dec4 #cj #d1djj #gjj #hj #a4ag ,dec4 #ca #ad1jjj #a1bjj #fe #a4ag ---------------------------------------- -------- #aijh4 ---------------------------------------- -------- ,jan4 #a ,holiday4 #a4ag ,jan4 #b #d1djj #gjj #ai #a4ag ,jan4 #c #c1ajj #a1jjj #ac #a4ag ,jan4 #d #b1djj #eej #ai #a4ag ,jan4 #e ,sunday4 #a4ag ,jan4 #f #fjj #bcj #ah #a4ag ,jan4 #g #a1ajj #cgj #ab #a4ag ,jan4 #h #a1ijj #a1ajj #bj #a4ag ,jan4 #i #ac1jjj #a1bjj #bb #a4ba ,jan4 #aj #aj1jjj #gjj #af #a4ag ,jan4 #aa #af1jjj #a1bjj #aa #a4ag ,jan4 #ab ,sunday4 #a4ag ,jan4 #ac #h1ejj #ij #f #a4bg ,jan4 #ad #af1jjj #aej #bc #a4ef ,jan4 #ae #bd1jjj #a1ajj #ai #a4ib ,jan4 #af #bh1jjj #a1jjj #ad #b4aj ,jan4 #ag #fe1jjj #dij #bc #a4ia ,jan4 #ah #g1jjj #a1fjj #ad #a4ff ,jan4 #ai ,sunday4 #a4ej ,jan4 #ba ,scrape1 #a4de in4 of sand removed4 ,jan4 #bc 444 444 444 #a4ag ,jan4 #bd #b1cjj #eej #ee #a4ag ,jan4 #be #a1ajj #hej #ie #j ,jan4 #bf ,sunday4 #j ,jan4 #bg #cjj #bhj #fj #j ,jan4 #bh #a1bjj #gjj #gj #j ,jan4 #bi #a1jjj #ijj #ge #j ,jan4 #cj #a1djj #fej #ej #j ,jan4 #ca #a1ajj #fjj #cf #j ---------------------------------------- -------- ,feb4 #a #gej #ej #be #j ,feb4 #b ,sunday4 #j ,feb4 #c #a1cjj #bbj #af #j ,feb4 #d #fjj #cgj #aj #j ,feb4 #e #gej #gjj #ba #j ,feb4 #f #b1jjj #fej #d #j ,feb4 #g 444 #daj #bf #j ,feb4 #h #ijj #afj #db #j ,feb4 #i ,sunday4 #j ,feb4 #aj #hej #dej #ah #j ,feb4 #aa #a1jjj #fjj #bf #j ,feb4 #ab #gej #cej #af #j ,feb4 #ac #gjj #abj #aj #j ,feb4 #ad #a1bjj #iej #dc #j ,feb4 #ae #e1ejj #a1jjj #bc #j ,feb4 #af ,sunday4 #j ,feb4 #ag #cc1jjj #f1ajj #cf #j ,feb4 #ah 444 #b1jjj #aa #j ,feb4 #ai #bh1jjj #i1jjj #abj #j ,feb4 #bj #bb1jjj #h1ejj #aij #j ,feb4 #bi 444 444 444 #j ---------------------------------------- -------- ,mar4 #a ,sunday4 #j ,mar4 #b #h1jjj #d1djj #ej #j ,mar4 #c #aa1jjj #b1ajj #bf #j ,mar4 #d #f1jjj #d1gjj #g #j ,mar4 #e #d1djj #aj1jjj #cf #j ,mar4 #f #g1jjj #g1djj #ej #j ,mar4 #g #i1ejj #f1ejj #bh #j ,mar4 #h ,sunday4 #j ,mar4 #i #aa1jjj #d1hjj #be #j ,mar4 #aj #h1ejj #a1bjj #bc #j ,mar4 #aa #f1ejj #b1djj #bj #j ,mar4 #ab #e1ijj #a1ejj #aa #j ,mar4 #ac #a1ijj #a1ajj #ab #j ,mar4 #ad #a1hjj #gjj #f #j ,mar4 #ae ,sunday4 #j ,mar4 #af #a1djj #gjj #h #j ,mar4 #ag #ijj #hjj #aa #j ,mar4 #ah #a1jjj #fej #h #j ,mar4 #ai 444 #fjj #ah #j ,mar4 #bj #a1cjj #gej #bj #j ,mar4 #ba #hjj #dhj #ah #j ,mar4 #bb ,sunday4 #j ,mar4 #bc #d1fjj #ddj #ai #j ,mar4 #bd #b1ejj #a1bjj #aj #j ,mar4 #be #a1fjj #fej #bj #j ,mar4 #bf #eej #daj #g #j ,mar4 #bg #ijj #ijj #bi #j ,mar4 #bh #fej #bej #db #j ,mar4 #bi ,sunday4 #j ,mar4 #cj #ejj #fej #bh #j ,mar4 #ca #gej #bij #cj #j ---------------------------------------- -------- ,apr4 #a #gej #cij #cb #j ,apr4 #b #a1ajj #bhj #dg #j ,apr4 #c #a1ejj #eej #gj #j ,apr4 #d #gjj #chj #d #j ,apr4 #e ,sunday4 #j ,apr4 #f #ddj #aej #d #j ,apr4 #g #fej #bgj #db #j ,apr4 #h #eej #baj #fe #j ,apr4 #i #cij #afj #ie #j ,apr4 #aj #ejj #acj #acj #j ,apr4 #aa #dcj #ade #ajj #j ,apr4 #ab ,sunday4 #j ,apr4 #ac #dij #afj #hj #j ,apr4 #ad #eej #agj #ij #j ,apr4 #ae #dbj #afj #ab #j ,apr4 #af #cfj #acj #ij #j ,apr4 #ba ,scraped1 #j4ab in4 of sand removed4 ,apr4 #bc #adj #adj 444 #j ,apr4 #bd #bjj ,lost4 #aej #j ,apr4 #be #he #eej #de #j ,apr4 #bf ,sunday4 #j ,apr4 #bg #ie #hej #ej #j ,apr4 #bh #gj #bbj #dh #j ,apr4 #bi #aaj #baj #ie #j ,apr4 #cj #gj #adj #bi #j ---------------------------------------- -------- ,may #a #acj #baj #fe #j ,may #b #adj #adj #ee #j ,may #c ,sunday4 #j ,may #d #he #baj #ge #j ,may #e #acj #aej #dh #j ,may #f #bcj #dcj #ej #j ,may #g #afj #ij #dj #j ,may #h #cge #dbe #g #j ,may #i #a1bji #ahj #f #j ,may #aj ,sunday4 #j ,may #aa #b1hjj #aej #ab #j ,may #ab #b1ijj #bbe #bf #j ,may #ac #a1hjj #dej #ec #j ,may #ad #b1gjj #eej #aj #j ,may #ae #iej #cjj #fe #j ,may #af #hjj #bej #di #j ,may #ag ,sunday4 #j ,may #ah #gjj #a1gjj #hj #j ,may #ai #cge #iej #ec #j ,may #bj #dbe #gjj #df #j ,may #ba #cjj #fjj #f #j ,may #bb #iej #bcj #ag #j ,may #bc #b1djj #cb #bh #j ,may #bd ,sunday4 #j ,may #be #a1ajj #hej #i #j ,may #bf #c1bjj #aej #ag #j ,may #bg #a1dej #age #h #j ,may #bh #a1jjj #acb #g #j ,may #bi #a1ajj #bcj #h #j ,may #cj ,holiday4 #j ,may #ca ,sunday4 #j ---------------------------------------- -------- ,june #a 444 444 444 #j ,june #b 444 444 444 #j ,june #c 444 444 444 #j ,june #d 444 444 444 #j ,june #e 444 444 444 #j ,june #f 444 444 444 #j ,june #g 444 444 444 #j ,june #h 444 444 444 #j ,june #i 444 444 444 #j ,june #aj 444 444 444 #j ,june #aa 444 444 444 #j ,june #ab 444 444 444 #j ,june #ac 444 444 444 #j ,june #ad 444 444 444 #j ,june #ae 444 444 444 #j ,june #af 444 444 444 #j ,june #ag 444 444 444 #j ,june #ah 444 444 444 #j ,june #ai 444 444 444 #j ,june #bj 444 444 444 #j ,june #ba 444 444 444 #j ,june #bb 444 444 444 #j ,june #bc 444 444 444 #j ,june #bf 444 444 444 #j ,june #bg 444 444 444 #j ,june #bh 444 444 444 #j ,june #bi 444 444 444 #j ,june #cj 444 444 444 #j ---------------------------------------- -------- ,july #a #hj #ge #c #j ,july #b #bij #bj #c #j ,july #c #cej #adj #d #j ,july #d ,holiday4 #j ,july #e ,sunday4 #j ,july #f #cjj #eb #d #j ,july #g #aaj #ce #b #j ,july #h #he #aje #b #j ,july #i #he #hj #c #j ,july #aj #cjj #fe #a #j ,july #aa #ade #ie #aa #j ,july #ab ,sunday4 #j ,july #ac #aae #aje #g #j ,july #ad #hjj #cd #a #j ,july #ae #ahj #afe #c #j ,july #af #ajj #ie #b #j ,july #ag #fe #fe #a #j ,july #ah #ch #bjj #bd #j ,july #ai ,sunday4 #j ,july #bj #ie #ca #a #j ,july #ba #gj #ajj #b #j ,july #bb #dej #ac #d #j ,july #bc #fej #cbe #d #j ,july #bd #a1fej #cbe 444 #j ,july #be #b1fjj #ee #b #j ,july #bf ,sunday4 #j ,july #bg #ce1jjj #a1bjj #f #j ,july #bh #a1bjj #fge #f #j ,july #bi #b1jjj #bgj #aa #j ,july #cj #hjj #aij #b #j ,july #ca #a1jjj #caj #f #j ,table #bj--,summary of ,results of ,experimental ,filters4 ,filter number44444 #a #b #c #d #e #f ,number of runs4444 #c #f #aa #ab #be #bh ---------------------------------------- ---------------------------- ,rate1 million gallons per acre per day3 ,maximum4444444 #a4ce #c4ie #g4if #ab4fj #cg4e #aah4i ,minimum4444444 #j4fb #b4cj #c4gc #e4gg #f4fh #g4a ,average4444444 #a4jf #c4bf #f4fi #aj4ag #bf4a #ch4ed ---------------------------------------- ---------------------------- ,length of run1 in days3 ,maximum4444444 #bcc4e #aej4e #ge4b #ij4i #dh4ga #ci4hc ,minimum4444444 #aha4g #db4j #ad4e #aj4a #j4fg #j4fb ,average4444444 #bjf4d #aji4f #dh4hi #dj4e #ad4da #ab4fa ---------------------------------------- ---------------------------- ,million gallons filtered per acre per run3 ,maximum4444444 #bdb4fa #dhd4df #ecd4fg #ifj4gb #a1dfc4ce #a1jbb4bg ,minimum4444444 #bjb4fj #ace4ff #ic4gi #ib4eg #ai4ec #ec4cb ,average4444444 #bah4eh #cjb4hb #cbf4gf #dag4bc #cgd4ad #cfa4ib ---------------------------------------- ---------------------------- ,cubic yards of sand removed per acre at end of each run3 ,maximum4444444 #bfi #bfi #fgb #a1fab #b1dbj #c1cfj ,minimum4444444 #bfi #acd #aja #acd #acd #aja ,average4444444 #bfi #bac #bgb #cib #ehc #fce ---------------------------------------- ---------------------------- ,cubic yards of sand removed per acre per million gallons filtered44444444 #a4bc #j4gj #j4hc #j4id #a4ee #a4gb ---------------------------------------- ---------------------------- ,average initial loss of head4444 #j4jg #j4ai #j4ea #j4gh #c4hh #e4ch ---------------------------------------- ---------------------------- ,turbidity1 influent3 ,maximum4444444 #abj #abj #abj #abj #ij #ajj ,minimum4444444 #b #b #b #b #b #b ,average4444444 #bj #bj #ba #bb #ah #ai ---------------------------------------- ---------------------------- ,turbidity1 effluent3 ,maximum4444444 #aa #ac #ag #ah #cj #cj ,minimum4444444 #j #j #j #j #j #j ,average4444444 #a #a #b #b #d #c ---------------------------------------- ---------------------------- ,percentage reduction #ie4j #ie4j #ij4e #ij4i #gg4h #hd4c ---------------------------------------- ---------------------------- ,bacteria1 influent3 ,maximum4444444#ahj1jjj #ahj1jjj #ahj1jjj #aaj1jjj #ahj1jjj #cg1ejj ,minimum4444444 #bb #bj #bb #bj #be #bd ,average4444444 #d1hjj #e1ajj #d1ejj #d1bjj #f1ijj #e1ijj ---------------------------------------- ---------------------------- ,bacteria1 effluent3 ,maximum4444444 #d1jjj #a1cjj #c1bjj #e1djj #ab1hjj #b1djj ,minimum4444444 #b #c #a #a #b #b ,average4444444 #afj #he #aaj #abj #aij #ahj ---------------------------------------- ---------------------------- ,percentage1 ,reduction4444444 #if4g #ih4c #ig4f #ig4c #ig4c #ig4j ---------------------------------------- ---------------------------- ,number of samples examined for bacillus coli in influent3 #aj c4c44444444 #edi #dgh #dgf #dcf #cbe #ccf #a c4c44444444 #efj #dib #dhf #dde #cce #cdb #j4a c4c444444 #ebe #dei #deb #dac #cah #cag #j4ja c4c44444 #eaa #ddc #dci #dje #cjh #cjd #j4jja c4c4444 #ejj #dcd #dbi #cid #bii #bid ---------------------------------------- ---------------------------- ,number of samples examined for bacillus coli in effluent3 #aj c4c44444444 #eab #deb #ded #djd #bif #cji #a c4c44444444 #eac #ded #deg #djf #bii #caa #j4a c4c444444 #dhj #dai #dbf #chc #bga #bhf #j4ja c4c44444 #dgh #djf #daj #cfg #bfa #bgf #j4jja c4c4444 #dgh #djf #daj #cfg #bfa #bgf ---------------------------------------- ---------------------------- ,number samples positive1 influent3 #aj c4c44444444 #bbf #baa #bja #beh #acf #aeb #a c4c44444444 #abg #abc #aaf #ajh #ha #ic #j4a c4c444444 #ee #ei #ed #ea #dc #db #j4ja c4c44444 #bf #cd #cc #cc #bg #be #j4jja c4c4444 #f #f #e #f #c #c ---------------------------------------- ---------------------------- ,number samples positive1 effluent3 #aj c4c44444444 #ajj #aji #acd #ih #id #ajf #a c4c44444444 #ea #fa #ee #ef #df #ej #j4a c4c444444 #i #ac #af #af #d #ac #j4ja c4c44444 #j #j #j #j #j #j #j4jja c4c4444 #j #j #j #j #j #j ---------------------------------------- ---------------------------- ,percentage of samples showing bacillus coli in influent3 #aj c4c44444444 #da4b #dd4b #db4b #ei4b #da4i #de4b #a c4c44444444 #bb4g #be4j #bc4i #bd4c #bd4b #bg4b #j4a c4c444444 #aj4e #ab4h #aa4i #ab4c #ac4e #ac4b #j4ja c4c44444 #e4a #g4g #g4e #h4b #h4h #h4b #j4jja c4c4444 #a4b #a4d #a4b #a4e #a4j #a4j ---------------------------------------- ---------------------------- ,percentage of samples showing bacillus coli in effluent3 #aj c4c44444444 #ai4e #bd4a #bi4e #bd4b #ca4g #cd4c #a c4c44444444 #aj4j #ac4d #ab4j #ac4h #ae4d #af4a #j4a c4c444444 #a4i #c4a #c4h #d4b #a4e #d4e #j4ja c4c44444 #j #j #j #j #j #j #j4jja c4c4444 #j #j #j #j #j #j ---------------------------------------- ---------------------------- ,cost per million gallons for sand handling44444 #j4dc #j4be #j4bi #j4cc #j4ed #j4fj ---------------------------------------- ---------------------------- ,interest charges at #c44444444444 #f4he #b4be #a4ab #j4gc #j4cb #j4bb ---------------------------------------- ---------------------------- ,total444444444 #g4bh #b4ej #a4da #a4jf #j4hf 4#hb ,coli tests presumptive4 ,,discussion ,allen ,hazen1 ,m4 ,am4 ,soc4 ,c4 ,e4 7by letter74--,this paper contains a most interesting and instructive record of the actual operation of a large filter plant1 and also a record of a number of experiments4 ,the author has described some useful arrangements for improving the efficiency or reducing the cost4 ,the utility of raking1 as an intermediate treatment between scrapings1 seems to have been clearly demonstrated4 ,its practical effect is to allow a greater quantity of water to be passed between scrapings1 thereby saturating--if the term may be used--the surface layer with clay and other fine matter before removing it1 instead of taking it off when only a thin surface layer of it has been thus saturated4 ,the large proportion of the total purification that takes place in passing through three reservoirs successively1 holding in the aggregate a quantity of water equal to about #g days' use1 is very striking4 ,taking all the records1 the percentage remaining after passing through these reservoirs1 is as follows3 ,sediment for the year1 #aiji-aiaj1 ,table #b44444444444444444444ag ,turbidities1 #e-year average1 ,table #c4444444444444444444444444be ,bacteria1 #e-year average1 ,table #d4444444444444444444444444444bd ,bacteria1 selected winter months with high numbers in the raw water44444444444444444444444444444444444 #bj ,bacteria1 selected summer months with high numbers in the raw water44444444444444444444444444444444444 #b4e ,there is considerable seasonal fluctuation in the results of settling and filtering1 as is shown in ,table #ba4 ,table #ba--;,average ,removal of ,turbidity and ,bacteria by ,washington ,filters for ,whole ,period1 ,arranged by ,seasons4 ,winter4 ,spring4 ,summer4 ,fall4 ,year4 ---------------------------------------- -------------------------- ,turbidity1 in raw #ace #if #add #db #aje parts per settled #cc #bh #bg #ae #bf million3 filtered #d #c #a #j4e #b ---------------------------------------- -------------------------- ,percentage settling #bd #bi #ai #cf #be left from3 filtering #ab #aj #d #c #h both #c #a #j4c #a #b ---------------------------------------- -------------------------- ,bacteria per raw #af1fjj #d1aej #d1ajj #a1ifj #f1gjj cubic settled #f1cjj #ihj #afj #bgj #a1idj centimeter3 filtered #adi #bi #ah #bb #ed ---------------------------------------- -------------------------- ,percentage settling #ch #bd #d #ad #bi left from3 filtering #b4d #c4j #aa4b #h4b #b4h both #j4ij #j4gi #j4dd #a4ab #j4ha ,the fluctuation in the efficiency of the plant as a whole by seasons is greater with the turbidity than with the bacteria4 ,during the winter the effluent contains #c of the turbidity of the raw water1 and in summer only #j4c per cent4 ,most of this difference is represented by the increased efficiency of the filters in summer1 and only a little of it by the increased efficiency of settling4 ,with bacteria1 on the other hand1 the seasonal fluctuation of the plant as a whole is comparatively small1 but the settling and storage processes are much more efficient in summer than in winter1 the filters being apparently less efficient4 ,the writer believes that they are only apparently less efficient1 and not really so1 the explanation being that some bacteria always grow in the under-drains and lower parts of the filter1 and are washed away by the effluent4 ,the average number of bacteria in summer in the settled water is #afj per cu4 cm4 and in the filtered water #ah4 ,these are very low numbers4 ,it is the writer's view that nearly all of these #ah represent under-drain bacteria1 and practically bear no relation to those in the applied water1 and1 if this view is correct1 the number of bacteria actually passing through the various processes is at all times less than the figures indicate4 ,in the warmer part of the year the difference is a wide one1 and the hygienic efficiency of the process is much greater than is indicated by the gross numbers of bacteria4 ,the reduction of the typhoid death rate has not been as great with the change in water supply as was the case at ,lawrence1 ,albany1 and other cities1 apparently because the ,potomac water before it was filtered was not the cause of a large part of the typhoid fever4 ,the sewage pollution of the ,potomac is much less than that of the ,merrimac and the ,hudson1 and it is perhaps not surprising that this relatively small amount of pollution was less potent in causing typhoid fever than the greater pollution of rivers draining more densely populated areas4 ,the method of replacing the washed sand hydraulically seems to have worked better than could have been reasonably anticipated1 and the writer believes that this was due1 in part1 to the excellent method of manipulation described in the paper4 ,it is his feeling1 however1 that part of the success is attributable to the very low uniformity coefficient of the sand4 ,in other words1 the sand grains are nearly all of the same size1 due to the character of the stock from which the filter sand was prepared2 and1 therefore1 there is much less opportunity for separation of the sand according to grain sizes than there would be with the filter sand which has been available in most other cases4 ,filter sand with a uniformity coefficient as low as that obtained at ,washington has been rarely available for the construction of sand filters1 and while the method of hydraulic return should certainly be considered1 it will not be safe to assume that equally favorable results may be obtained with it with sands of high uniformity coefficients until actual favorable experience is obtained4 ,the writer believes that in calculating the cost of the water used in the plant itself the price chosen by the author1 covering only the actual operating expenses of pumping and filtering1 is too low4 ,the capacity of the whole ,washington ,aqueduct system is reduced by whatever quantity is used in this way1 and1 in calculating the cost of sand handling1 the value of the water used should be calculated on a basis which will cover the whole cost of the water1 including all capital charges1 depreciation1 operating expenses1 and all costs of every description4 ,on this basis the water used in the sand-handling operations would probably be worth five or more times the sum mentioned by the author4 ,the cost of operation of the plant has come within the estimates made in advance1 and has certainly been most reasonable4 ,the cost of filter operations has averaged only about #ej cents per million gallons1 and is so low that it is obvious that the savings which may be made by introducing further labor-saving appliances would be relatively small4 ,it will be remembered that ten or fifteen years ago the cost of operating such filters under ,american conditions was commonly from #b to #e per million gallons4 ,the experiments represented by ,tables #ag to #ai1 inclusive1 serve to show that preliminary filtration1 or multiple filtration1 or any system of mechanical separation is incapable of entirely removing the finer clay particles which cause the residual turbidity in the effluent4 ,they also show that this turbidity may be easily and certainly removed by the application of coagulant to the raw water during the occasional periods when its character is such as to require it4 ,these general propositions were understood by those responsible for the original design of the plant1 as is shown by the author's quotations4 ,these experiments1 however1 were necessary in order to demonstrate and bring home the conditions to those who thought differently1 and who believed that full purification could be obtained by filtration alone1 or by double filtration1 without recourse to the occasional use of coagulant4 ,the experiments briefly summarized in ,table #bj are of the greatest interest and importance4 ,six small filters1 otherwise alike and like the large filters1 all received the same raw water and were operated at different rates to determine the effect of rate on efficiency4 ,that the experimental results from the filter operating at the same rate as the large filters were on the whole somewhat inferior to those from the large filters for approximately the same period1 may be attributed to the fact that the experimental filter was new while the large filters had been in service for some time and had thereby gained in efficiency4 ,the greatest difference was in the coli results in ,table #bj1 where it is shown that #bd of the #aj-;cu4 cm4 effluent samples from the experimental filter contained coli1 in comparison with only from #a to #c of such samples from the main filters4 ,the results from the experimental filter operating at a rate of #a1jjj1jjj gal4 per acre daily may fairly be excluded1 as the effluent probably contained more under-drain bacteria in proportion than filters operated at higher rates4 ,the number of bacteria in the filter operating at a #c1jjj1jjj-;gal4 rate were #a4g of those in the applied water2 for the filter operating twice as fast1 the percentage was #b4d2 and1 for the one operating more than ten times as fast1 was only #c4j2 thus indicating a surprisingly small increase in the number of bacteria with increase in rate4 ,further and more detailed study by the writer of the unpublished individual results1 briefly summarized in ,table #bj1 confirms the substantial accuracy of the comparison based on the average figures as stated in that table4 ,it must be kept in mind1 in considering these results1 that the number of bacteria in each case is made up of two parts1 namely1 those coming through the filter--which number is presumably greater as the rate is greater--and1 second1 those coming from harmless growths in the under-drains and lower parts of the filter--the numbers of which per cubic centimeter are presumably less as the rate is greater--and these two parts1 varying in opposite directions1 may balance each other1 as they seem to do in this case1 through a considerable range4 ,it may thus be that the number of bacteria really passing the filter varies much more with the rate than is indicated by the gross results4 ,it is also of interest to note that the sand filter 7called a preliminary filter7 in ,table #ah1 filled with the same kind of sand1 when operated at an average rate of #ej1jjj1jjj gal4 per acre daily for a year1 allowed #ah of the applied bacteria to pass1 in comparison with #c found in ,filter ,no4 #f of ,table #bj1 operated at an average rate of #ch1jjj1jjj gal4 per acre daily4 ,there was one point of difference in the manipulation3 the preliminary filter was washed by a reversed current of water1 as mechanical filters are washed1 while ,filter ,no4 #f was cleaned by scraping off the surface layer1 as is usual with sand filters4 ,whether the great difference in bacterial results with a relatively small difference in rate is to be attributed to this difference in manipulation the writer will not undertake to state4 ,if the experimental results of ,table #bj indicate correctly the conditions which obtain in filtering ,potomac water1 then increasing the rate of filtration so as to double it1 or more than double it1 would make but little difference in the quality of the effluent as measured by the usual bacterial methods4 ,if the increase in rate were accompanied by the preliminary filtration of the water1 then1 presumably1 there would be little change in the quality of the effluent1 and the maintenance of excellent results might be incorrectly attributed to the influence of the preliminary filter4 ,it would also seem that the apparatus which is sometimes used for determining and controlling the rate with more than the ordinary degree of precision is hardly justified by such experimental results as those presented by the author4 ,in contrast to these results may be mentioned those obtained by ,mr4 ,h4 ,w4 ,clark1#a for experimental filters operated with ,merrimac ,river water1 at rates ranging from #c1jjj1jjj to #af1jjj1jjj gal4 per acre daily4 ,the results are the average of nearly two years of experimental work1 the period having been nearly coincident with that covered by the author's experiments1 and of many hundreds of bacterial analyses of each effluent1 and form1 with the author's experiments1 the most thorough-going studies of the effect of rate on efficiency that have come to the writer's attention4 ,mr4 ,clark's results are given in ,table #bb4 ,table #bb4 ,b4 ,coli in #a cu4cm4 ,effective ,rate ,bacteria per 7percentage size of in gallons cubic ,bacterial of positive sand4 ,filter ,no4 acre daily4centimeter inefficiency4 tests74 ---------------------------------------- ------------------------------ #j4bh ,a #c1jjj1jjj #dh #ii4a #e4j #j4be ,b #e1jjj1jjj #he #ih4d #bd4j #j4bb ,c #g1ejj1jjj #aje #ih4a #be4j #j4bb ,d #aj1jjj1jjj #aaj #ih4j #be4j #j4bb ,e #af1jjj1jjj #bhj #ie4j #ch4j ,it will be seen that the number of bacteria passing increases rapidly with the rate1 and whether the total number of bacteria is considered or the ,b4 coli results1 the number passing is approximately in proportion to the rate4 ,in other words1 doubling the rate substantially doubles the number of bacteria in the effluent4 ,this is entirely in harmony with all the ,lawrence experimental results extending over a period of #bj years4 ,there have been occasional apparent exceptions1 but1 on the whole1 experience with ,merrimac ,river water has uniformly been that more bacteria pass as the rates are higher4 ,the theory sometimes advanced1 that the efficiency of filtration is controlled to a certain extent by gelatinous films1 and that1 as far as thus controlled1 is less dependent on rate1 would not seem to be borne out by these results4 ,the ,merrimac ,river water1 carrying large amounts of organic matter1 would certainly seem better adapted to the formation of such films than the clay-bearing ,potomac water1 comparatively free from organic matter2 but it is the ,potomac water which seems to show the least influence of rate on efficiency4 ,footnote #a3 ,journal1 ,new ,england ,water-,works ,association1 ,vol4 #bd1 p4 #ehi4 ,the experiments show that turbidity passes more freely at the higher rates with the ,potomac water1 as has also been found to be the case with other clay-bearing waters4 ,in the last lines of ,table #bj are given cost per million gallons for filtering at various rates4 ,there is no discussion of these figures1 and as they differ considerably from those which the writer has been accustomed to use1 the calculation in ,table #bc1 made three years ago for a particular case1 may be of interest4 ,table #bc--,relative ,cost of ,filtering at ,different ,rates4 ,nominal rate1 in millions of gallons per acre daily3 ---------------------------------------- -------- #c #e #aj #bj ---------------------------------------- ------------------------------ ,percentage which average yield is of nominal rate4444444444 #he #hj #ge #fe ---------------------------------------- ------------------------------ ,average output per acre1 in millions of gallons per day4444444 #b4ee #d4jj #g4e #ac4j ---------------------------------------- ------------------------------ ,cost of that part of filters per acre dependent on rate44444 #ab1jjj #bj1jjj #dj1jjj #hj1jjj ---------------------------------------- ------------------------------ ,cost of that part of filters per acre not dependent on rate44444 #ej1jjj #ej1jjj #ej1jjj #ej1jjj ---------------------------------------- ------------------------------ ,total cost of filters per acre44444444444444 #fj1jjj #gj1jjj #ij1jjj #acj1jjj ---------------------------------------- ------------------------------ ,cost per million gallons of capacity444 #bj1fjj #ad1jjj #i1jjj #f1ejj ---------------------------------------- ------------------------------ ,cost per million gallons of average daily output4444444444 #bd1djj #ag1ejj #ab1jjj #aj1jjj ---------------------------------------- ------------------------------ ,capital charges and depreciation at #f on cost per million gallons444444444444444 #d4jj #b4hg #a4ig #a4fd ---------------------------------------- ------------------------------ ,operating expenses1 the same at all rates44444444444444444 #a4jj #a4jj #a4jj #a4jj ---------------------------------------- ------------------------------ ,total cost of filtering1 excluding pumping1 storage1 and all auxiliaries4444444 #e4jj #c4hg #b4ig #b4fd ---------------------------------------- ------------------------------ ,relative cost444444444 #a4bi #a4jj #j4gg #j4fh ,when the costs of pumping1 pure-water reservoirs usually necessary1 etc41 are taken into account 7which add equally to the cost at all rates71 the cost of filtering will vary less with the rate than is indicated4 ,the effect of rate on cost1 as calculated in ,table #bc1 and also the percentages of the bacteria of the raw water found in the effluents by the author and by ,mr4 ,clark1 are shown on ,figure #aj4 ,considering all these results together1 and also all the other evidence known to the writer bearing on this point1 it seems clear that filters are not as sensitive to changes in rate1 within reasonable limits1 as has been frequently assumed2 but1 on the other hand1 there is usually a substantial increase in the percentage of bacteria passing through a filter with increased rate4 ,filters furnish relative1 not absolute1 protection against infectious matter in the raw water4 ,the higher the bacterial efficiency1 the more complete is this relative protection4 ,the cost of filtering does not decrease in inverse ratio to the rate1 but at a much slower rate4 ,this is especially true with rates of more than #e1jjj1jjj or #f1jjj1jjj gal4 per acre daily4 ,in general1 a rate of filtration may rationally be selected at which the value of the possible danger resulting from an increase in rate is equal to the saving that may be made in cost by its use4 ,this point must be a matter of individual judgment4 ,the tendency of the last few years has been to use higher rates1 or1 in other words1 to cheapen the process and to tolerate a larger proportion of bacteria in the effluent4 ,the use of auxiliary processes has been favorable to this1 especially the use of chloride of lime1 in connection with either the raw water or the effluent4 ,illustration3 ,figure #aj--,rate ,million ,gallons ,per ,acre ,daily4 ,by the judicious use of this substance1 efficiency may be maintained while using higher rates than would otherwise have been desirable4 ,the writer believes that there will be many cases where the added risk of using too high a rate is not worth the relatively small saving in cost that accompanies it4 ,george ,a4 ,johnson1 ,assoc4 ,m4 ,am4 ,soc4 ,c4 ,e4--,this paper contains information of an exceedingly interesting nature4 ,there is comparatively little difficulty in obtaining accurate figures on the cost of construction of water purification works1 but1 with costs of operation of such works1 it is different4 ,the data available in published reports and papers are usually more or less fragmentary1 and unexplained local conditions with reference to the character of the raw water1 the cost of labor and supplies1 and methods of apportioning these costs1 introduce variables so wide as frequently to render the published figures almost useless for purposes of comparison4 ,mr4 ,hardy's paper is noteworthy in that it presents certain relatively new features of slow sand filter operation which have been only lightly touched on in water purification literature up to the present time4 ,these refer particularly to means whereby a filter may be continued in service without removing a portion of the surface layer of the filter surface itself when the available head has become exhausted1 and to methods whereby washed sand may be expeditiously and more economically restored to the filter than has been the case hitherto4 ,sand handling is the most important item of expense in the operation of a slow sand filter4 ,quite recently a charge of #a4ej per cu4 yd4 for sand scraping1 transportation to sand washers1 washing1 and restoring to the filter1 was not considered exorbitant1 but the improved methods developed during recent years at ,washington1 ,philadelphia1 ,albany1 and more recently at ,pittsburg 7at all of which places hydraulic ejection plays an important part71 have shown the feasibility of reducing this figure by nearly1 if not quite1 two-thirds4 ,the practice observed at ,washington of raking over the surface of the sand layer when the available head becomes exhausted1 in order to avoid the cost and loss of time necessitated by shutting down the filter and scraping off the surface layer1 is unquestionably one of the most striking advances in slow sand filter operation in recent years4 ,in rapid sand filter operation1 to prolong the period of service between washings1 agitation of the filter surface has been used to advantage for many years4 ,the full value of surface raking may not be generally appreciated1 but the results which have followed a trial of this procedure at ,washington1 ,philadelphia1 and ,pittsburg have shown that the output of filtered water between scrapings may be doubled or trebled thereby1 with no injury to the filter itself or to the quality of the filtered water4 ,the cost of raking over the surface of a #a-;acre slow sand filter unit is less than #aj at all the above-mentioned places1 which fact in itself shows the great saving in money and time effected by periodically substituting surface raking for scraping4 ,under ordinary conditions it has been found that a filter can be raked to advantage at least twice between scrapings4 ,in the case of filters thus raked1 a deeper penetration of suspended matter into the sand layer is inevitable1 but at ,pittsburg1 as at ,washington1 such penetration does not extend more than about #b in4 below the filter surface4 ,when the filter is finally scraped1 a deeper layer is removed1 of course1 but it is clearly more economical to remove a deep layer at one operation than to remove separately several thinner layers of an equal total thickness4 ,the lost-time element is an important one1 and at ,washington this was the main reason for trying surface raking4 ,it became necessary to increase the output of the filters1 and the ordinary scraping consumed so much time that the sand-handling force was increased1 working day and night4 ,the raking expedient introduced at this time overcame this1 and ,mr4 ,hardy states that it is still followed when the work is at all pressing4 ,the speaker has found at ,pittsburg1 as ,mr4 ,hardy has found at ,washington1 that raking is nearly if not quite as effective as scraping in restoring the filter capacity4 ,eleven years ago the speaker was connected with the preliminary investigations into the best methods of purifying the ,potomac ,river water for ,washington4 ,it then appeared that while for the greater part of the time during an average year the ,potomac ,river could be classed among the clear waters of the ,east1 there were periods when excessive turbidity made it necessary to consider carefully methods of preparatory treatment before this water could be filtered effectively and economically4 ,as ,mr4 ,hardy has said1 considerable prejudice existed against the use of a coagulating chemical1 and the expedient was therefore adopted of giving the water a long period of sedimentation in order to remove enough of the suspended matter to allow the clarified water to be treated on slow sand filters4 ,the expert commission1 consisting of ,messrs4 ,hering1 ,fuller1 and ,hazen1 recommended the occasional use of a coagulating chemical1 but this recommendation was not carried out4 ,the ,potomac ,river is somewhat peculiar1 in that the turbidity of its waters1 as shown by the results presented in ,mr4 ,hardy's paper1 ranges from #c1jjj to practically nothing4 ,the bacterial content also varies widely1 and ,mr4 ,hardy's tables show this variation to be from #gf1jjj to #cbe per cu4 cm4 ,such a water as this requires particularly careful preparatory treatment4 ,the ,dalecarlia ,reservoir has a capacity of something like #b days' storage1 the ,georgetown ,reservoir the same1 and the ,mc,millan ,park ,reservoir nearly #c days1 making a total sedimentation of more than #g days4 ,without the use of a coagulant1 it is significant that during a period of five years1 even with #g days' sedimentation1 the average maximum turbidity of the water delivered to the filters was #ajf parts per million1 and the maximum average turbidity in one month was #bej parts per million4 ,the water filtration engineer can readily understand that waters as turbid as this cannot be treated economically and efficiently in slow sand filters4 ,it would appear that coagulating works might advantageously have been installed at the entrance to the ,dalecarlia ,reservoir4 ,if this had been done1 and coagulant had been added to the water at times when it was excessively turbid1 a considerably shorter period of subsequent sedimentation than now exists would in all probability have rendered the water at all times amenable to efficient and economical slow sand filter treatment4 ,the prejudice in ,washington against the use of coagulants has also manifested itself in other localities1 but the results which have been obtained during the past twenty years from rapid sand filters and from slow sand filters1 treating waters previously coagulated with salts of iron or alumina1 have shown how thoroughly unreasonable were these objections4 ,in this connection it is interesting to note that there are in the ,united ,states more than #cej rapid sand filter plants1 and that nearly #ab of the urban population of ,continental ,united ,states is being supplied with water filtered through rapid sand filters1 in connection with all of which a coagulating chemical is used in the preparatory treatment4 ,table #bd--,typhoid ,fever ,death ,rates in ,cities of the ,united ,states with ,populations in #aiaj of #ajj1jjj1 or ,more4 ,statistics gathered by correspondence and from ,reports of the ,bureau of the ,census1 ,department of ,commerce and ,labor1 ,mortality ,statistics4 ,note4--,statistics from ,birmingham1 ,ala41 ,dayton1 ,ohio1 ,fall ,river1 ,mass41 ,louisville1 ,ky41 ,memphis1 ,tenn41 ,oakland1 ,cal41 and ,providence1 ,r4 ,i41 are not included1 as they are incomplete4 ,columns3 ,a - ,average for six years1 #aijj-je1 inclusive4 ,b - ,average for five years1 #aijf-aj1 inclusive4 ,c - ,average for #aa years1 #aijj-aa1 inclusive4 ,typhoid ,fever ,death ,rate ,city4 per #ajj1jjj ,population4 ---------------------------------------- #aijf #aijg #aijh #aiji #aiaj ,a ,b ,c ---------------------------------------- -------------------- ,albany1 ,n4 ,y4 #bj #bj #aa #ai #ae #be #ag #ba ,atlanta1 ,ga4 #ej #fd #dg #dd #dc #fe #ej #eh ,baltimore1 ,md4 #cd #da #ca #bc #da #cf #cd #ce ,boston1 ,mass4 #bb #aj #bf #ad #aa #bc #af #bj ,bridgeport1 ,conn4 #aj #ac #ac #ac #i #ae #ab #ad ,buffalo1 ,n4 ,y4 #bd #bi #ba #bc #bj #bi #bc #bf ,cambridge1 ,mass4 #ah #aj #aj #i #ab #ah #ab #ae ,chicago1 ,ill4 #ah #ah #ae #ab #ad #bg #af #bb ,cincinnati1 ,ohio #ga #df #ai #ac #f #ed #ca #dd ,cleveland1 ,ohio #bj #ai #ac #ab #ai #ea #ag #cf ,columbus1 ,ohio #de #ch #aaj #ag #ac #fa #de #ed ,denver1 ,colo4 #fh #fg #eh #bd #cj #cg #di #db ,detroit1 ,mich4 #bb #bh #bb #ai #af #ag #bb #ai ,grand ,rapids1 ,mich4 #ci #cj #cj #ag #bg #cd #bh #ca ,indianapolis1 ,ind4 #ci #bi #bf #bb #ca #gf #cj #ee ,jersey ,city1 ,n4 ,j4 #bj #ad #aj #h #aj #ai #ab #af ,kansas ,city1 ,mo4 #ch #dj #ce #bc #ch #dh #ce #db ,los ,angeles1 ,cal4 #ah #bc #ai #ah #ab #ce #ah #bg ,lowell1 ,mass4 #g #i #bd #aa #ba #ai #ad #ag ,milwaukee1 ,wis4 #ca #bf #ag #ba #de #ai #bh #bc ,minneapolis1 ,minn4 #cc #bf #ah #bj #eh #ch #bi #cd ,nashville1 ,tenn4 #ff #he #fb #ec #dh #ed #eh #ef ,newark1 ,n4 ,j4 #ah #bd #ab #aa #ac #ag #af #ag ,new ,haven1 ,conn4 #ed #cj #cd #bj #ag #dd #ca #ch ,new ,york1 ,n4 ,y4 #ae #ag #ab #ab #ab #ai #ad #ag ,new ,orleans1 ,la4 #cj #ef #ca #be #bh #dj #cd #cg ,omaha1 ,nebr4 #bh #bd #bb #ca #ge #bj #cf #bg ,paterson1 ,n4 ,j4 #d #aa #aj #e #g #be #g #ag ,philadelphia1 ,pa4 #gd #fj #cf #bb #ag #dg #db #de ,pittsburg1 ,pa4 #ada #ace #ecaacaaba #acb #ga #ajd ,richmond1 ,va4 #dd #da #ej #bd #bb #ff #cf #ec ,rochester1 ,n4 ,y4 #ag #af #ab #i #ac #ae #ac #ad ,st ,louis1 ,mo4 #ah #af #ae #ae #ad #cc #af #be ,st ,paul1 ,minn4 #ba #ag #ab #bj #bj #ad #ah #af ,san ,francisco1 ,cal4 444 #eg #bg #ag #ae #bj #bi #bd ,scranton1 ,pa4 #aa #gf #aa #aa #ad #ah #ce #bf ,syracuse1 ,n4 ,y4 #aj #af #ae #ab #cj #ad #ag #ae ,toledo1 ,ohio #de #cf #dj #ca #cb #cf #cg #cf ,worcester1 ,mass4 #ab #ad #aj #h #af #ag #ab #ae ,washington1 ,d4 ,c4 #eb #cf #ci #cc #bc #ei #cg #di ,footnote #a3 ,filtered water section4 ,allegheny ,district not included4 ,attention has repeatedly been called to the fact that the relatively high typhoid death rate in ,washington1 since the filter plant was installed1 was a possible indication that the filters were inefficient4 ,it is true that there has not been the marked reduction in the typhoid death rate in ,washington1 following the installation of the water filtration works1 that has been observed in other cities in ,america4 ,for the six years prior to the date on which filtered water was supplied to the citizens of ,washington1 the average typhoid fever death rate was #ei per #ajj1jjj population1 as against #cg per #ajj1jjj for the five years following1 a reduction of #cg per cent4 ,at ,albany1 ,n4 ,y41 where the first modern slow sand filter was built in #ahii1 the typhoid death rate has been reduced by #ge per cent4 ,at ,cincinnati1 ,ohio1 the average death rate from typhoid ranged around #ej per #ajj1jjj for years1 but since the installation of the filtration plant it has been reduced to a point which places that city1 with respect to freedom from typhoid fever1 at the head of all the large cities in ,america2 in #aiaj the death rate from typhoid in ,cincinnati was #f per #ajj1jjj4 ,similarly1 at ,columbus1 ,ohio1 where the typhoid death rate before the installation of the filtration plant in #aijf was even higher than at ,cincinnati1 it was reduced to less than #ac per #ajj1jjj in #aiaj1 whereas1 for the previous five years1 it was #fa per #ajj1jjj4 ,philadelphia1 before the installation of the filtration works1 had a typhoid death rate of #fj or more per #ajj1jjj1 and in #aiaj the death rate from this disease was #ag4 ,pittsburg1 at least that part of it now supplied with filtered water1 for years had a typhoid death rate of more than #acj per #ajj1jjj1 but the present rate is about #ab per #ajj1jjj4 ,table #be--;,average ,monthly ,results for the ,period1 #aije-aiaj4 ,columns3 ,a - ,period of sedimentation in days4 ,b - ,turbidity in parts per million4 ,c - ,bacteria per cubic centimeter4 ,percentage ,removed ,reservoirs4 ,a ,b ,c -------------------- ,turbidity ,bacteria ---------------------------------------- --------- ,river 444 #ajf #f1djj 444 444 ,dalecarlia #b4b #ej #e1jjj #ec #bb ,georgetown #b4b #ch #c1djj #bd #cb ,mc,millan #b4h #bf #b1jjj #ca #da ---------------------------------------- --------- ,totals and averages #g4b 444 444 #ge #fi ,while it may perhaps seem unreasonable to single out ,washington as a particular sufferer in this respect1 it is highly probable that a large share of the typhoid is still caused by secondary infection1 flies1 impure milk1 and private and public wells4 ,the speaker remembers distinctly that ten years ago1 when he made an investigation into the purity of the water of about #ajj public wells in that city1 a large number of them showed unmistakable evidence of being polluted with sewagic matter4 ,conclusive evidence would be secured to dispel any doubt as to the sanitary quality of the filtered product if hypochlorite of lime were added to the filtered water throughout one year or throughout the typhoid months4 ,it seems strange to the speaker1 that for this1 if for no other reason1 this safe and non-injurious germicide has not as yet been used at ,washington1 in view of the fact that at the present time it is being used continuously or intermittently in the treatment of the water supplies of scores of the most important cities of this country1 among which may be mentioned ,new ,york1 ,philadelphia1 ,cincinnati1 ,pittsburg1 ,st4 ,louis1 and ,minneapolis4 ,morris ,knowles1 ,m4 ,am4 ,soc4 ,c4 ,e4 7by letter74--,this description of the operation of the ,washington ,filtration ,works is timely and of great interest4 ,it is ten years since the writer1 in collaboration with ,charles ,gilman ,hyde1 ,m4 ,am4 ,soc4 ,c4 ,e41 presented a similar record for the ,lawrence1 ,mass41 filter4 ,that paper was the first complete1 detailed1 and continuous history of the actions and results obtained for a long period of time with such a purification works4#a ,since then1 the art of filtration has advanced in many ways1 particularly in regard to the methods of cleaning slow sand filters and in the accompanying processes4 ,it is well1 therefore1 again to take account of stock and see really what progress has been made4 ,therefore1 ,mr4 ,hardy's paper1 giving a description of the operations of a system thoughtfully designed1 after long consideration of the problem1 and of operations carried on under efficient and economical administration1 with thorough record of all details1 should furnish a groundwork for the careful consideration of the question stated above4 ,the writer1 using as a text some of the ideas given in the paper1 but more particularly some of those becoming prevalent elsewhere1 desires to discuss methods and costs of operation1 especially in relation to sand handling2 and to offer suggestions looking toward greater efficiency1 as well as economy1 in carrying out the standard and well-tried methods4 ,theory of ,slow ,sand ,filtration4--,first1 what is the process of slow sand filtration8 ,the answer to this question involves many factors1 some of which are even yet but imperfectly understood4 ,in the early history of filtration1 at the time of the construction of the ,london filters1 only the straining capacity of the sand bed1 to remove gross particles1 was known4 ,later1 when the organic contents of water had become better understood1 the chemical or oxidizing powers of the process were recognized as performing an important part4 ,finally1 co-existent with the discovery of the so-called germ theory of disease1 a study of the bacterial action of filters resulted in the recognition of its importance4 ,it is now universally thought that each of these factors performs its useful function2 that the size of the sand1 the amount of organic matter remaining on the surface of the bed1 the turbidity of the applied water1 and the bacterial content of the influent1 are some of the things on which depends the determination of the relative importance of each4 ,footnote #a3 ,transactions1 ,am4 ,soc4 ,c4 ,e41 ,vol4 ,,xlvi1 p4 #beh4 ,engineers have been taught to believe1 by the ,german school of thought1 that the film of organic matter on the surface of the sand plays a very important role in filtration4 ,this ,schmutzdecke1 as it is called1 has been considered so precious that stress has been placed on treating it with great care4 ,it was not to be wholly removed at the time of cleaning1 and it was not to be walked on1 or indented1 or in any other way consolidated or destroyed4 ,in fact1 in some cases1 the wasting of the first water after cleaning has been advocated1 for the reason that not a sufficient amount of this organic film would be left on top of the sand to begin the filtration process properly immediately after the cleaning4 ,in late years1 however1 there has been a tendency to depart from this fundamental doctrine of slow sand filtration4 ,various new processes for cleaning the sand surface have been advocated2 some of these partly destroy and others completely exterminate any semblance of a bacterial film on the sand bed4 ,these ideas1 advanced without any real and serious discussion of their intrinsic merits1 or their effects on the public health1 are not founded on long continuous records of such results as are necessary to establish confidence in the final value of any of these methods4 ,rapid advances along this line have been made more recently1 notwithstanding the occurrence of notable instances of trouble and the resultant need of complete repair of filtration beds4 ,because of the rough treatment of the sand surface1 a penetration of organic matter and filth into the bed had taken place4 ,this caused deep clogging1 prevented the usual yield of water1 and brought about a lessened bacterial efficiency1 due to the attempt to force water through the filters1 and because some organic matter and growths in the lower part of the bed had furnished a breeding place for more bacteria4 ,all these endeavors to reduce the work of cleaning have been commendable1 because scraping and sand handling are the items of greatest expense in slow sand filter maintenance4 ,every one has been desirous of minimizing this cost4 ,however1 as the writer will endeavor to show1 it seems that attempts along this line should be with the idea of doing more economically1 as well as efficiently1 the things which one knows will accomplish the proper results1 rather than unwisely to adopt new methods which have not been tried for a long enough period to determine their effect on the public health4 ,pittsburg ,methods4--,when first taking up the problem of design in ,pittsburg1 in #aijb1 the writer had presented to him for consideration and adoption1 a suggestion that a certain method of cleaning sand filters1 which would involve the washing of the sand in place 7similar to that recently tried at the ,jerome ,park ,experiment ,station1 ,new ,york ,city71 would be advisable and economical4 ,the decision then made has never been regretted4 ,as this plan involved such a complete departure from those principles which had been well tried and had proven successful1 it was believed that it was not safe to adopt such a method on the municipal filtration works1 from which the people were to derive their drinking water4 ,there is more to be considered in such a problem than mere economy of operation2 the economy of human life1 the effect on which requires far longer than a few months of trial to determine1 is a much more important factor4 ,believing that no one should depart1 until after a long period of conclusive experimentation1 from that principle which is known to be safe 7viz41 to take off a small portion of the clogging surface71 the writer studied to determine more efficient and economical methods of accomplishing this end4 ,a device for scraping the material1 in just the same way as with shovels1 but more efficiently and more exactly1 was developed by ,george ,p4 ,baldwin1 ,m4 ,am4 ,soc4 ,c4 ,e41 under the general supervision of the ,bureau of ,filtration1 of which the writer was in charge4 ,however1 on account of the unfortunate and earlier arrangement of other constructive matters1 which the ,city's ,legal ,department advised could not be changed without upsetting the contract1 the entrance doors to the original forty-six filters were not built large enough to permit the rapid and economical transfer of these machines1 and1 as this act takes so large a proportion of the total time of operation1 it has not been found economical to use them4 ,the additional ten filters1 recently constructed1 with doors especially designed and large enough to pass the machines1 have not yet been placed in operation4 ,this is said to be on account of lack of funds and of employees4 ,therefore1 there has been no opportunity to demonstrate what the scraping machines can do1 under the conditions for which they were designed to operate4 ,the restoring machine1 a complementary device in mechanical operation1 which simply replaces the sand in the same condition that it would be if wheeled back1 but1 with a small percentage of moisture1 has accomplished its purpose well and economically4 ,the sand is placed in the filters so that there is no further settling2 with a smooth surface1 needing no additional adjustment2 with absolutely no possibility of sub-surface clogging2 and with the filters starting off exceedingly well in operative results4 ,washington ,methods4--,in ,washington1 it is stated that the filters are still cleaned by the old-fashioned method of scraping with shovels1 throwing the sand into piles1 and afterward removing it with a movable ejector4 ,between scrapings there is also an occasional mid-period action of raking the unwatered sand surface1 for the purpose of stirring up the dirty film4 ,this process does not remove any of the clogging material from the bed1 but it is said that no injurious effects are produced1 and that it is economical4 ,it is stated that the so-called ,brooklyn method1 of stirring the surface of the sand while the water is on the bed1 has been tried at ,washington1 but with unsatisfactory results4 ,it seems to have been advocated with greater fervor in some other places4 ,the method of dry raking does not remove the dirty material1 but loosens up the pores of the surface1 and through this porosity permits clogging to penetrate deeper into the filter4 ,the method of raking with water on the bed1 although it removes some of the organic dirt1 also permits deeper penetration of the remainder4 ,the latest devised system of washing the sand in place1 by upward spraying with water1 called the ,blaisdell method1 thoroughly destroys the ,schmutzdecke above1 and1 at the same time1 must permit the formation of a subsidiary one below4 ,in the ,nichols method1 the material removed by shovel scraping is conveyed by an ejector to a portable separator1 where it receives a single washing2 the dirty water overflows to the sewer1 while the washed sand is discharged through a hose and deposited on the recently scraped surface4 ,as the latter is partly impregnated with impurities1 there is1 by this process1 a tendency toward sub-surface clogging4 ,all these processes are marked and serious departures from the well-tried method of cleaning slow sand filters1 which1 it is well known1 will operate successfully to purify polluted river waters and make them safe to drink4 ,in all there is the danger that they have not been sufficiently and carefully tried1 under scientific observation1 as to results and possible effects on the public health1 to be sure that the bacterial efficiency can long continue to be satisfactory1 with the application of specifically infected waters4 ,it is dangerous1 and may even jeopardize the safety of human lives1 to experiment on water which is furnished for drinking purposes4 ,there is also the added danger1 well known from past experience1 that in a few years 7it may be more or less1 depending on the extent and intensity of the new workings7 the filters will need renovation1 partly1 if not wholly1 throughout the entire bed4 ,thus1 considering the total cost during a long term of years1 the apparently cheaper method may become the most expensive4 ,there is also an interesting query in regard to the ,washington method of replacing sand in the filters1 and it is worthy of most careful thought and attention4 ,if the process described can be carried on with success and safety1 it will prove to be a long and progressive step in the methods of operation4 ,the difficulty1 however1 is in determining from any short-term runs whether such a process can be continued permanently without impairing the efficiency of the sand bed4 ,apparently good conditions may change1 after a few years' trial1 and be followed by unsafe results and predicaments4 ,this replacing of sand with whatever dirt and detritus may travel with it in the carrying water is certainly not equivalent to the care with which it has been understood that sand should be deposited in filters4 ,it is not comparable with the care with which it is placed1 when wheeled from a washer1 where dirty water overflows the lip1 or where it is placed by a machine restorer in the filter1 where the transporting water also overflows the weir and is carried to the sewer4 ,these cheap and rapid methods of doing the work1 advanced in the interests of economy1 and the idea that sand filters1 receiving polluting waters1 can operate at higher rates than those which we have demonstrated1 and1 therefore1 have been led to believe are safe1 is a speeding up of the whole organization and of operating conditions4 ,it is like speeding up a machine for the purpose of getting a greater output1 with the usual result that fast running means quicker wearing out of both man and machine4 ,quicker operations generally mean carelessness in doing the work1 especially in municipal service4 ,carelessness is engendered by the thought that such work can be handled in a rough and rapid way1 and1 further1 by the ridicule of all these things1 which we have learned to be careful about1 as old-fogyish1 out-of-fashion1 and archaic4 ,carelessness in operation breeds contempt for the art4 ,some of the less efficient filter plants1 from the standpoint of effect on the public health1 may reflect such ill-considered methods ,economy with ,efficiency in ,operation4--,it is particularly important to find out whether one can secure the desired economy1 and1 at the same time1 the required efficiency4 ,the development of efficiency in every line of human endeavor is receiving much attention at present1 and not the least cause for this is the growing recognition of the demand for a high standard of service for the expense caused4 ,one of the first requirements is to have well-defined ideals and standards4 ,when one knows how to secure a good and safe result1 it is unwise to depart therefrom for a mere whim1 or to secure a supposedly lessened expense1 unless other facts be also determined favorably4 ,the desire for economy must be tempered by good sense1 which means that one should be willing to change a method only when the wisdom of such has been clearly demonstrated4 ,efficient service can only be secured by strict discipline1 accompanied by fair dealing4 ,this means employing no more men than are actually necessary1 paying them on the basis of the standard of service and output produced1 taking an interest in the working conditions1 and providing for their health and welfare4 ,about twelve years ago1 the writer made some investigations of the efficiency of laboring gangs in scraping and handling sand at filter beds1#a and found that ten men was the most economical number to use in scraping the surface of the ,lawrence filter1 as then built and operated4 ,this result was determined by numerous studies of the output per man per minute1 with different numbers of men working under different conditions4 ,this same sort of study has been carried further by adepts in the art1 in reference to shop and similar management1 but one fails to find corresponding development along this line in municipal organization except by a few of the scattered ,bureaus of ,municipal ,research4 ,these results1 also1 have related to a few of the more common and general factors1 such as determining the cost per mile1 or per square yard1 of street cleaned1 or per million gallons of water pumped4 ,footnote #a3 ,transactions1 ,am4 ,soc4 ,c4 ,e41 ,vol4 ,,xlvi1 p4 #bia4 ,the cost of the management of water-works1 one of the largest factors of public enterprise1 has never been investigated extensively and thoroughly4 ,there is much possibility in planning for greater efficiency and in determining what can be accomplished under economical administration4 ,every one is aware of the multiplicity of men in municipal service4 ,some of these are entirely incompetent1 others partly so2 the recent appointees may be more efficient1 but the majority of them gradually deteriorate under the subtle influence of the prevailing atmosphere1 and each new incoming administration places more and more men on the work1 without reason or necessity4 ,all these tendencies have made the cost and maintenance of public work greater and greater1 and1 at the same time1 have resulted in frequently and steadily decreasing the output and efficiency per employee4 ,the ,washington situation1 however1 presents an admirable contrast to this1 because of the methods of administration of the public works of the ,district of ,columbia and their freedom from petty political influence4 ,the limited number of employees has tended toward economy1 and rendered this plant the envy of all who have desired to obtain good management4 ,its cost items have been looked on as a result long hoped for1 but seldom obtained4 ,it is to be regretted1 therefore1 that such an abrupt change in methods of removing clogging material and replacing sand has taken place without years of experimental trial on filters not furnishing drinking water to the public1 and without an attempt1 under such excellent conditions1 to maintain the efficiency by a better labor output and by improved working and machine methods in the performance of the older and established order of doing things4 ,in preparing water for the use of the people1 the realms of the unknown are so much larger than those which have been investigated and developed that there may be many undiscovered factors affecting the public health1 and many ways in which it is dangerous to depart from well-known and surely safe methods4 ,who can say that in some subtle and1 at present1 unknown manner1 the failure in some places1 where filtration is practiced1 to reduce the death rate from typhoid fever may not be due to the introduction of radical departures from the older1 slower1 safer1 and more efficient methods which have produced such excellent results1 both in ,america and in ,europe8 ,further1 in cases where there has been a falling off in the typhoid death rate1 the failure to secure an accompanying improvement in general health conditions1 which follows so closely in communities supplied by water filtered in accordance with the more conservative principles1 may be due to the introduction of some of these not thoroughly tried processes4 ,some day full information may be available as to the influence of these methods of plant operation on the health of the community4 ,until that time1 is it not a much better policy to follow the principles which have been proven by many years of experience to produce safe results1 and to make the foremost object the improvement of the methods of operation in accordance with these established truths8 ,there is opportunity for the upbuilding of greater efficiency in the conduct of employees and in securing the maximum output1 by establishing more comfortable and healthful conditions than usually exist4 ,the elimination of political influence from municipal service is also a task which challenges the people of to-day1 and the operating and managing engineer is in a position to perform an important part in accomplishing this end4 ,the number of employees can be reduced to those actually needed1 and the way opened for the employment of men who thoroughly understand the necessities of honesty and efficiency in the conduct of public affairs4 ,it should be remembered that to design and construct well is only half the job2 to operate economically and efficiently is even more of a problem than to build1 and requires just as good talent1 just as keen appreciation of the various problems1 and is even more essential to public welfare4 ,it seems to the writer that the logical development of the art of obtaining economy as well as efficiency should be along these lines1 rather than to revolutionize methods1 without having a long-period test of their value1 and at the same time allow political influences to control1 to a large extent1 the labor item4 ,preliminary ,treatment4--,the decision as to the preliminary treatment of the ,potomac ,river water before filtration is of interest1 particularly because various other conclusions have been reached in different sections of the country4 ,however1 in the main1 these decisions have been due to differences in the character of the waters1 but it must be evident that they have sometimes been the result of ill-considered action1 or the desire to promote some special interest4 ,the use of preliminary filters1 which involves a large investment1 is not always to be commended1 particularly because at times of reasonably good water the removal of some of the organic matter is really injurious and lessens the effect of the final filters4 ,for a long time1 the writer has believed that1 where other things are equal1 and where there is no important reason for double or preliminary filtration1 long periods of storage1 accompanied by the use of coagulant at times of severe and extreme muddiness1 as planned at ,washington1 solves the problem in the most practical and economical way4 ,it is true that the investment for a large storage basin may equal1 or even exceed1 that required for preliminary filters2 but the influence of storage on the quality of raw water is never injurious1 and1 by ripening the condition of the water1 may be greatly beneficial in the process of filtration4 ,the storage available in such a basin makes it possible to shut off the supply from the river during the worst conditions of the water4 ,the duration of the most troublesome spells ordinarily does not exceed a few days1 and it is usually possible to secure sufficient capacity in the basin to tide over these periods4 ,then again1 long periods of storage1 in addition to assisting in breaking up organic matter1 permit the dying out of bacteria1 particularly many of the pathogenic kind1 and1 therefore1 the water is rendered much safer from this standpoint4 ,in other words1 there is additional insurance in long storage against the faulty and careless operation of incompetent filter employees4 ,the addition of coagulant1 especially the fact that only a very small investment of capital is required for the necessary apparatus for dosing the water1 and that the cost of the coagulating materials has to be met only when used1 seems to give the process1 in a most satisfactory manner1 the requirement for economical management and thoroughness in preparing the water for final filtration4 ,parking ,public ,works4--,it is disappointing that the author has not mentioned some of the steps contemplated in reference to the landscape treatment of the ,washington filtration area4 ,probably every one has been impressed by the barren aspect of the works as they are approached1 and as one looks over them4 ,recently1 however1 it is stated that some steps have been taken to lay out the grounds1 treat the surface in an attractive manner1 and make a park of the area4 ,the writer has a firm opinion that when an investment is made for public works1 it costs but little in addition to construct buildings along appropriate architectural lines1 to treat the grounds in a pleasing manner1 and to make the entire works a credit to the municipality from an artistic standpoint4 ,when treated on broad lines1 such areas become public parks1 and afford open breathing places for the residents1 and1 if near centers of population1 may well be equipped with playground facilities for the children4 ,when thus developed they should have care1 that the planting and equipment should not deteriorate and the last state become worse than the first4 ,the influence which these ever-present examples of attractiveness have on the community is becoming better recognized by students of social progress1 and there seems to be no doubt that spending money on such features is not only desirable from the artistic standpoint1 but is justified on practical grounds as well4 ,it is cheaper than to create parks1 when necessity and demand can no longer be resisted1 by buying property and occasionally tearing down buildings and constructing de novo4 ,that this work is now being done in ,washington1 even after construction1 is certainly a recognition of the advisability of original efforts in this direction4 ,george ,c4 ,whipple1 ,m4 ,am4 ,soc4 ,c4 ,e4 7by letter74--,mr4 ,hardy's paper is an excellent presentation of the results of the operation of the ,washington water filtration plant from the time of its construction in #aije until ,june1 #aiaj4 ,papers of this character are altogether too infrequent1 and the actual results from the filters now in use are not readily accessible in detailed form4 ,yet it is only by studying the results obtained by filters in actual use that improvements can be made and the art advanced4 ,among the many important facts brought out by ,mr4 ,hardy1 only a few can be selected for discussion4 ,one of these is the operation of filters under winter conditions4 ,it is well known that the efficiency of sedimentation basins and filters is lower during winter than at other times1 yet it is just at this season of the year that there is the greatest danger of typhoid fever and similar water-borne diseases being transmitted by water4 ,most of the great typhoid epidemics have occurred during cold weather1 and the very use of the term winter cholera is of significance4 ,apparently1 typhoid bacilli and similar bacteria are capable of living and retaining their vitality longest during that season of the year4 ,just why this is so1 bacteriologists have not satisfactorily explained4 ,doubtless many factors are involved4 ,because of the increased viscosity of the water1 sedimentation takes place less readily at lower temperatures1 and inasmuch as sand filtration is partly dependent on sedimentation1 the efficiency tends to fall off in cold weather4 ,during winter some of the external destroying agencies are less potent1 such as the sterilizing effect of sunlight1 and the presence and activity of some of the larger forms of microscopic organisms which prey on the bacteria4 ,another factor may be the greater amount of dissolved oxygen normally present in water during cold weather1 as experiments have shown that dissolved oxygen favors longevity4 ,still another reason for the larger numbers of bacteria that pass through a water filter during cold weather may be the effect that the low temperature has on the size of the bacteria themselves4 ,a few experiments made recently by the writer appear to indicate that at low temperatures the gelatinous membrane which surrounds the bacterial cells tends to become somewhat contracted1 thus decreasing the apparent size of the bacteria as seen under the microscope4 ,either this contraction occurs1 or the cells themselves are smaller when they develop in the cold4 ,it is possible also that low temperature affects the flagella of the organisms in the same way4 ,it is not unreasonable to suppose that the effect of low temperature is to form what may be1 in effect1 a protective coating around the cells1 which tends to make them smaller1 less sticky1 and less subject to outside influences4 ,this would tend to make them pass through a filter more readily4 ,in line with this idea also is the well-known fact that disinfection is less efficient in cold water than in warm water4 ,another way of viewing the matter is that cold retards the growth of bacteria on the filter1 thus reducing the effect of the ,schmutzdecke4 ,still another view of the greater danger from bacterial contamination in winter is the theory that cold prolongs the life of the bacteria by merely preventing them from living through their life cycle and reaching natural old age and death as rapidly as in warm weather4 ,another topic in ,mr4 ,hardy's paper which has interested the writer is that of preliminary filters4 ,the experiments described at length indicate clearly that such devices would prove of little or no benefit under the conditions existing in ,washington1 and that when the river contains considerable amounts of suspended clay nothing less than chemical coagulation will suffice to treat the water so that the effluent will be perfectly clear4 ,preliminary filters have been used for a number of years at various places and with varying success4 ,in few instances have they been operated for a sufficient length of time or been studied with sufficient care to determine fully their economy and efficiency as compared with other possible methods of preliminary treatment4 ,among other experiments on this matter are those made at ,albany1 ,n4 ,y41 and published by ,wallace ,greenalch1 ,assoc4 ,m4 ,am4 ,soc4 ,c4 ,e41 in the ,fifty-ninth ,annual ,report of the ,bureau of ,water for the year ending ,september #cjth1 #aiji4 ,the ,hudson ,river water used at ,albany is quite different in character from the ,potomac ,river water used at ,washington1 as it is less turbid and contains rather more organic matter4 ,the results obtained in these experiments showed that during the summer the number of bacteria in the effluent from the experimental sand filter used in connection with a preliminary filter did not differ widely from the number found in the effluent of the city filter where there was no other preliminary treatment than sedimentation4 ,in the winter1 however1 the numbers of bacteria did not increase in the effluent from the experimental filter as they did in the effluent from the city filter4 ,this is shown by ,table #bf1 taken from the report mentioned4 ,apparently1 therefore1 at ,albany the benefits of the preliminary filter1 as far as bacterial efficiency is concerned1 would be confined to a short period of three or four months in each year4 ,under such circumstances it may well be questioned whether the advantages of preliminary filtration justify its cost4 ,table #bf--,results of ,experiments with ,preliminary ,filter at ,albany1 ,n4 ,y4 ,month1 ,bacteria ,bacteria ,bacteria in,bacteria in #aijf4 in raw in pre- effluent effluent water4 liminary from from filter experimentalcity filter4 effluent4sand filter4 ---------------------------------------- --------------- ,march #acc1dhj #cf1jjj #aea #gjf ,april #gg1dbj #d1haj #gb #aee ,may #ae1hjj #b1bej #dh #cg ,june #d1ebj #ceh #ch #cd ,july #b1jij #afc #be #bb ,august #b1gdj #aba #cf #bb ,september #h1bhj #dde #bj #bd ,october #ch1cej #d1bce #fg #bbg ,november #fg1iaj #ae1egj #ccg #cda ,december #fde1ejj #be1ddj #add #b1ghc ---------------------------------------- --------------- #aijg4 ,january #abg1efj #d1ffj #dh #ddc ,february #bh1jjj #a1hjj #ac #aaf ,on the diagram1 ,figure #aa1 will be found various data taken from the published records of the ,albany filter1 from #ahii to #aiji4 ,these data include3 ,the numbers of bacteria before and after filtration2 the percentage of bacteria remaining in the effluent2 the average quantity of water filtered1 in millions of gallons per day2 the quantities of water filtered between scrapings2 the turbidity of the raw water2 the cost of filtration1 including capital charges and cost of operation2 and the typhoid death rates of the city per month4 ,several points are brought out conspicuously by this diagram4 ,one is the uniformly low death rate from typhoid throughout the entire period4 ,the filter was operated from #ahii until the fall of #aijg with raw water taken from what is known as the ,back ,channel4 ,since then it has been taken from a new intake which extends into the ,hudson ,river itself4 ,until the fall of #aijh the preliminary treatment consisted merely of sedimentation1 but since then the water has received an additional preliminary treatment in mechanical filters operated without coagulant1 along the lines of the experiments just mentioned4 ,during this time the average rate of filtration of the sand filter has not changed materially1 although it is said that the maximum rate has been increased since the preliminary filters were put in service4 ,the study of the bacteriological analyses shows that the best results were obtained during #aijb1 #aijc1 and #aijd4 ,since then the numbers of bacteria in both the raw and filtered water have increased4 ,this was especially noticeable during the winters of #aijg and #aijh when the water was taken from the new intake4 ,it will be interesting to compare the results after the preliminary filters have been operated for a long period to ascertain their normal effect on efficiency and on the increased yield4 ,illustration3 ,figure #aa--;,filters at ,albany1 ,n4 ,y4 ,results of ,operation4 #ahii-aiji4 ,compiled from data in ,annual ,reports4 ,another fact to be drawn from the plotted ,albany data is the increase in the cost of filtration1 both in capital charges and in operation4 ,from #ahii until #aijf the cost of operation1 including the cost of low-lift pumping1 was approximately #e per million gallons of water filtered2 and the total cost of filtration1 including capital charges1 was about #aj per million gallons4 ,during the year ending ,september #cjth1 #aiji1 the cost of operation had increased to #g4fc per million gallons1 and the total cost of filtration to #ae4ib per million gallons1 or approximately #ej in three years4 ,table #bg--,results of ,bacteriological ,analyses of ,samples of ,water at ,peekskill1 ,n4 ,y41 ,before and ,after ,filtration4 ,bacteria per cubic centimeter4 ,raw ,clear ,effluent,effluent,effluent,effluent ,tap in ,date4 water4 reser- ,no4 #a4 ,no4 #b4 ,no4 #c4 ,no4 #d4 city4 voir4 ---------------------------------------- ---------------------------- #aiji4 ---------------------------------------- ---------------------------- ,december #bith #aij #ajj 444 444 444 444 444 ---------------------------------------- ---------------------------- #aiaj4 ---------------------------------------- ---------------------------- ,february #aeth #ace #aj #aj #cj #bj 444 #bfe ,march #cast #bbe #ej #be #de #fj 444 #ce ,may #ahth #cjj #bi #bb #bf #ce #dc #cf ,july #fth #cjj #dd #i #c #da #aj #ca ,august #afth #fj #e #j #d #a #ac #ae ,october #c;d #eej #ad #ab #ad #ch 444 444 ,november #bast #cae #bb #bf #ag #f 444 444 ---------------------------------------- ---------------------------- #aiaa4 ---------------------------------------- ---------------------------- ,january #beth #dae #g #h #d #f 444 #g ---------------------------------------- ---------------------------- ,average #bgg #cj #ad #af #bf #bb #fe ,table #ag--7;,continued47 ,tests for ,b4 ,coli4 ,percentage of ,samples ,quantity of water ,containing ,b4 ,coli4 tested4 --------------------- ,raw4 ,filtered4 --------------------------------------- #j4a cu4 cm4 #j #j #a4j cu4 cm4 #bj #j #aj4j cu4 cm4 #dj #j ,as a matter of record1 the results of a series of analyses made at ,peekskill1 ,n4 ,y41 during #aiaj are presented in ,table #bg4 ,a sand filter was constructed for the water supply of this city in #aiji1 and put in operation in ,december4 ,the filter has a capacity of #d1jjj1jjj gal4 per day4 ,the supply is taken from ,peekskill ,creek1 and the water receives about one week's nominal storage before flowing to the filters4 ,an aerator is used before filtration during the summer1 when algae are likely to develop in the reservoir4 ,the filter was installed after an epidemic of typhoid which was apparently caused by an infection of the water supply4 ,normally1 the water has been little contaminated1 but the supply is subject to accidental contamination at any time1 among other possible sources of infection being the camps of workmen now engaged in constructing the ,catskill ,aqueduct for ,new ,york ,city4 ,table #bh--;,average ,results of ,chemical ,analysis at ,peekskill1 ,n4 ,y41 ,made at ,intervals of ,six ,weeks ,during #aiaj4 ,parts per ,parts per ,million4 ,million4 ---------------- ---------------- ,raw ,filtered ,raw ,filtered water4 water4 water4 water4 ---------------------------------------- ----------------------------- ,turbidity #b4 #j ,total residue #gj4 #gf4jj ,color #be4 #bj4 ,loss on ignition #ai4jj #ag4jj ,nitrogen as albumi- ,fixed residue #ej4jj #ei4jj noid ammonia #j4aab #j4jgf ,iron #j4ag #j4ac ,nitrogen as free ,total hardness #ch4gj #de4aj ammonia #j4jbd #j4jjf ,alkalinity #cc4ij #db4fj ,nitrogen as nitrites #j4jja #j4jja ,incrustants #d4fj #d4ej ,nitrogen as nitrates #j4jf #j4jf ,chlorine #b4fj #b4gj ,f4 ,f4 ,longley1 ,assoc4 ,m4 ,am4 ,soc4 ,c4 ,e4 7by letter74--,in this paper the author has presented a mass of data which will be welcomed by engineers engaged in water purification work1 because complete operating records form a substantial basis for improvement in the art1 and are often the inspiration for interesting discussions and the exchange of experiences of different observers whose views are mutually appreciated4 ,recent tendencies in filtration engineering have been largely in the direction of reducing the cost of operation4 ,a comparison of the operating costs of the earlier ,american plants of about a decade ago1 with those here presented of the ,washington plant1 is very gratifying to those who have been intimately connected with the latter work4 ,through perfection in design and reasonable care in operation1 the cost of filter cleaning1 which is a very considerable part of the total cost1 has been reduced to an unusually low figure1 without any sacrifice in efficiency1 and in the interests of the public health4 ,table #ad shows that1 from the first year1 there has been a progressive increase in the total cost of operation per million gallons filtered1 but this has not meant an increase in the annual total expenditure4 ,the largest percentage of increase in any item has been in ,care of ,grounds and ,parking1 and covers much-desired landscape improvements4 ,aside from this1 the principal factor affecting the table of costs has been the reduction in water consumption in the ,district of ,columbia4 ,nothing pertaining to this reduction has produced any corresponding reduction in the force required for the maintenance and operation of the filtration plant1 office and laboratory1 and pumping station1 though probably there has been some reduction in filter cleaning4 ,obviously1 then1 the total cost per million gallons would increase4 ,this decrease in consumption has been brought about by the elimination of waste in the distribution system1 which is not in the same department as the filtration plant1 but with regard to which a word may not be amiss in connection with this discussion4 ,the ,washington ,aqueduct was built half a century ago on lines which at that time were considered extraordinarily generous4 ,until recently1 therefore1 there has been no occasion for concern over the high rate of consumption4 ,during recent years1 however1 the use and waste of water have increased1 reaching a climax under unusual conditions in the winter of #aijd-je4 ,the maximum capacity of the aqueduct system is about #ij1jjj1jjj gal4 ,the maximum daily consumption at the time mentioned arose almost to #ajj1jjj1jjj gal41 with the result that1 before normal conditions were restored1 the reservoirs of the system were almost depleted4 ,this had a beneficial effect1 as provision was made for an active campaign for reducing the waste of water1 which was known to be very large4 ,these investigations1 using the pitometer1 were begun in ,july1 #aijf1 and have been pursued continuously since that time1 with most excellent results4 ,up to ,january1 #aiji1 leaks aggregating about #ab1jjj1jjj gal4 per day were detected and eliminated1 and about half the house services had still to be covered by the pitometer bureau4 ,although this reduction in waste has brought about an apparent increase in the cost of filtration1 its economical results have been far-reaching4 ,the causes which brought about this investigation also resulted in securing an appropriation for the study of the question of increased supply4 ,the writer was in charge of these studies1 and the most significant conclusion was that1 owing to the excellent results of the efforts for waste restriction1 the total consumption and waste of water in the district during the next few years would be far enough below the safe working capacity of the existing aqueduct system to make it entirely safe to postpone the construction of new works1 involving the expenditure of several million dollars1 in spite of the threatening conditions of a few years ago4 ,there has been so much controversy over typhoid fever in the ,district of ,columbia that the writer hesitates to discuss this subject4 ,viewing the situation through the perspective of several years1 however1 it does not seem to be as hopeless as the criticisms of four or five years ago would lead one to believe4 ,in ,table #i1 showing the typhoid death rates1 out of nine years given prior to #aije-jf1 when the filters were started in operation1 only one shows an annual death rate as low as the highest one since that year4 ,further than this1 the annual average typhoid death rate for the period since that year has been one-third lower than for a corresponding period before the filters were started4 ,the exhaustive researches of the ,public ,health and ,marine ,hospital ,service into this whole question1 covering a period of about four years1 have raised the present filtered water supply of the ,district of ,columbia above any well-founded criticism4 ,there has long been a strong and growing feeling that the water supply1 before filtration was introduced1 had been blamed for more than its share of the typhoid1 and this is borne out by much evidence that has been presented from time to time4 ,it is not an unreasonable conjecture1 therefore1 that perhaps the reduction of one-third in the total typhoid death rate may represent a much larger reduction in that part of the total which was due to polluted water alone2 and that1 as the authorities in the ,district of ,columbia and in certain other cities1 particularly in the ,south1 are now recognizing1 the fight against much of the remaining typhoid must be in the direction of the improvement of milk supplies1 precautions against secondary infection1 and attention to a large number of details surrounding the individual1 which may effectively protect him against the insidious attack of the disease favored by unknown agencies4 ,experiments in ,filter ,cleaning4 ,the author refers to the difficulty encountered during the first two summers in keeping the filters cleaned fast enough to maintain the capacity of the plant4 ,the real seriousness of this may be judged from the following facts4 ,the average increase in loss of head on all the filters for the entire year1 ,july #ast1 #aijf1 to ,july #ast1 #aijg1 was about #j4jec ft4 per day4 ,during the #aijf period of low capacity under discussion1 the loss of head on twelve of the filters increased for a period of eight days at the average rate of #j4de ft4 per day1 or about nine times the normal rate of increase4 ,this difficulty was caused by the presence of large numbers of micro-organisms in the applied water4 ,during the first summer 7#aijf7 this fact was not recognized1 but the sudden decrease in capacity was supposed to have been caused by the unusually high and long-continued turbidity which prevailed during that summer in the ,potomac ,river1 and persisted in the water supplied to the filters even after about four days of sedimentation in the reservoirs4 ,during the second summer 7#aijg7 the same phenomenon of suddenly and rapidly increasing losses of head appeared again1 but without any unusual turbidity in the applied water4 ,investigation1 however1 showed the presence of large quantities of organisms1 particularly melosira and synedra1 in the applied water1 and examinations in subsequent years have shown a periodic recurrence of these forms in quantities sufficient to cause the trouble mentioned4 ,in ,june1 #aijg1 examination showed repeatedly more than #a1jjj and #a1ejj standard units of melosira per cu4 cm41 and one count showed nearly #c1jjj standard units4 ,several expedients were tried in an effort to restore the rapidly decreasing capacity of the filters4 ,one of the earlier conjectures as to the cause of the trouble was that it might be due to the accumulation of large quantities of air under the surface of the sand1 as air had been observed bubbling up through the sand1 especially in filters which had been in service for some time4 ,the expedient was tried1 therefore1 of draining the water out of the sand and then re-filling the filter in the usual manner from below1 in the hope of driving out the entrained air4 ,presumably this treatment got rid of the air1 but it did not restore the capacity of the filter1 as the point of maximum resistance was in the surface of the sand and not below it4 ,as the author states1 raking the filters was tried and found to give results which were satisfactory enough to meet the emergencies already referred to4 ,when the filters were first put in operation1 in the fall of #aije1 the method of bringing back the capacity of a filter after the end of a run was to remove all the dirty sand to a depth determined by the marked discoloration caused by the penetration of the clay turbidity4 ,this sometimes necessitated the removal of large quantities of sand at a cleaning1 as the turbidity was exceedingly fine1 and penetrated at times to a depth of #c or #d in4 ,with the idea of effecting an economy in the cost of cleaning the filters1 a schedule of experiments was arranged shortly before ,july #ast1 #aijg4 ,the general object of the experiments was to determine1 first1 the relative costs of all different methods tried2 second1 whether the removal of only a thin layer of sand1 or the mere breaking up of the surface of the sand by thorough raking1 would give the filter its proper capacity for the succeeding run2 third1 whether the filters under these treatments would maintain a high standard of quality in the effluents2 fourth1 whether the continued application of any less thorough method than the one then in use might materially affect the future capacity of the filters4 ,to this end the filters were divided into four groups which1 during a period of about six months1 were subjected to treatments as follows3 ,group ,a4--,filters scraped deep at the end of each run2 ,group ,b4--,filters scraped light at the end of each run2 ,group ,c4--,filters raked at the end of each run1 until raking failed to bring back the proper capacity2 then they were scraped light1 and at the end of the next run the raking was resumed2 ,group ,d4--,light scrapings and rakings alternate at ends of runs4 ,the term deep scraping means the removal of practically all the discolored sand1 in accordance with the usual practice prior to the beginning of these experiments2 light scraping means the removal of only a thin surface layer of sand4 ,this depth has usually averaged about #c_/h in4 ,raking means the thorough breaking up of the clogged surface of the filter by iron-toothed rakes1 to a depth of about #a or #b in4 ,results4--,a general summary of the results of these experiments is given in ,table #bi1 which also shows the relative costs of the different methods per million gallons of water filtered4 ,a normal period of #i months just prior to the beginning of these experiments shows a labor cost 7corresponding to that in ,table #bi7 of #j4bi-a_/d per million gallons filtered4 ,table #bi--;,average ,results4 ,columns3 ,a - ,group4 ,b - ,number of filters4 ,c - ,number of days of service4 ,d - ,million gallons filtered4 ,e - ,cost of labor per treatment4 ,f - ,sand removed in cubic yards4 ,g - ,sand removed in cubic yards4 ,h - ,cost of labor4 ,i - ,bacteria per cu4 cm4 in effluent4 ,j - ,turbidity in effluent4 ,per ,million ,per ,run3 ,gallons ,filtered ,i ,j ---------------------------------------- ---------- ,a ,b ,c ,d ,e ,f ,g ,h ---------------------------------------- ----------------------- ,a #e #hb #bba4b #fh4dd #bae #a4aa #j4cji #ac #a ,b #i #cf #aja4d #bi4be #hd #j4hc #j4bhh #af #a ,c #e #ba #fj4j #aj4ib #bd #j4dj #j4ahb #ah #a ,d #aj #cb #hf4j #bj4aj #df #j4ed #j4bcd #bb #a ,capacity of ,filters4--,the capacity of the filters under the different methods of treatment are shown in a general way in ,table #bi for days of service and millions of gallons filtered per run4 ,this element by itself is decidedly in favor of the deep scrapings1 and least in favor of the repeated rakings4 ,a clearer conception of the capacities of the filters under these different conditions may be obtained from the four diagrams1 ,figure #ab1 showing1 for the four different groups1 the average number of days of service of the successive runs4 ,the diagram for ,group ,a shows that the variations in the period of service of the filters scraped each time to clean sand follow a more or less definite curve from year to year4 ,for the period covered by this curve1 the tendency seems to be toward a slight decrease in capacity from year to year1 as shown by the lower average maximum and minimum in the second year than in the first4 ,group ,b shows a sudden decrease in capacity following the first light scrapings and1 since that time1 a low but quite constant capacity4 ,group ,c shows a constantly decreasing capacity with successive rakings4 ,the only significance attaching to the curve after the first raking is the prohibitively low capacity indicated1 and the ineffectiveness of the measures taken to restore the capacity after the sixth raking4 ,group ,d1 after the first raking1 shows a prohibitively low and constantly decreasing capacity4 ,the diagrams for ,c and ,d indicate a dangerous reduction in capacity if long persisted in4 ,the method followed with ,group ,c may be dismissed with the statement that it is entirely insufficient1 and would be of use only in the rarest emergencies4 ,as far as the question of capacity is concerned1 these diagrams indicate that a filter in normal condition may safely be raked once4 ,it is believed that the constantly decreasing capacity shown in ,group ,d is not due so much to the rakings as to the small quantities of sand removed at the alternate scrapings1 and therefore it would not be proper to condemn this method of treatment without a further trial in which this defect was remedied4 ,this view seems to be supported by the results of ,group ,b4 ,the low but approximately constant capacity there shown would undoubtedly have been higher if a greater depth of sand had been removed each time4 ,illustration3 ,figure #ab--;,average ,number of ,days of ,service of ,successive ,runs for ,groups ,a1 ,b1 ,c1 and ,d4 ,quality of the ,effluent4--,the averages given in ,table #bi show but little difference in the bacterial contents of the effluents from the four groups of filters4 ,all are entirely satisfactory1 and the differences in favor of one method or another are small4 ,in looking for possible differences in the quality of the effluents from the four groups1 it was thought that such differences might be most apparent at a time when the entire plant was working under the most adverse conditions4 ,the bacterial counts1 therefore1 were summarized for the period from ,december #bc;d1 #aijg1 to ,january #fth1 #aijh1 inclusive1 following a period of high turbidity and high bacteria in the raw water1 with results as follows3 ,group4444444 ,a ,b ,c ,d ,maximum44444 #bjd #agh #ahi #bjf ,minimum44444 #fa #de #fb #eg ,average44444 #abj #ajg #ajd #aee ,the following is a summary of the turbidity results for a similar period3 ,group4444444 ,a ,b ,c ,d ,maximum44444 #aj4h #aa4g #h4g #i4c ,minimum44444 #f4g #d4g #f4b #e4g ,average44444 #h4g #h4c #g4b #g4i ,these numbers1 though high1 do not show any significant differences4 ,all the averages for each group are less than the lowest maximum1 and all are greater than the highest minimum1 and therefore vary less than do the individual filters1 from other causes1 within the different groups4 ,future ,capacity of the ,filters4--,an indication of the dangers which might affect the future capacity of the filters was shown in the above discussion of the present capacity4 ,a more effective way of showing this was obtained by a study of the initial resistances or losses of head in the four groups4 ,a filter kept in ideal condition would show no increase in this initial loss of head from one run to the next4 ,if there is such an increase1 it means that at some future time measures more heroic than ordinarily used would be necessary to restore the proper capacity4 ,the average initial losses of head for the different groups are plotted on the diagram1 ,figure #ac4 ,group ,a shows an initial loss of head1 increasing gradually but slightly during more than two years of service4 ,in ,group ,b the initial loss of head increased in a manner similar to that in ,group ,a1 up to the time of the beginning of these experiments2 after which the increase becomes more rapid4 ,groups ,c and ,d show conditions generally similar to ,group ,b1 with some variations which are self-explanatory4 ,conclusions4--,the quality of the effluents from all four groups was satisfactory1 and no consistent difference was apparent in favor of one or another method of treatment4 ,the method pursued with ,group ,c was entirely insufficient to maintain the capacity indefinitely4 ,the methods pursued in ,groups ,b and ,d were both insufficient1 but would have been more effective if a greater depth of sand had been removed4 ,the costs of treatment of ,groups ,b and ,d were less than for ,group ,a4 ,it appears1 then1 that a treatment which would be more economical than the old method of ,group ,a1 and would still maintain the proper capacity1 would be one similar to that of ,groups ,b or ,d1 with the removal of a quantity of sand greater than was done in the case of these two groups1 but less than in the old method4 ,illustration3 ,figure #ac--;,average ,initial ,losses of ,head for ,groups ,a1 ,b1 ,c1 and ,d for ,successive ,runs4 ,at the time the above results were summarized1 it was proposed to proceed with the filter treatment along the lines just mentioned4 ,the writer did not have an opportunity to study the subsequent results1 as he was transferred to other work4 ,a statement by the author of any new facts that may have come to light in this connection would be of interest4 ,mention should be made1 too1 of another expedient that was used to hasten the restoration of the capacity of a filter1 which proved to be a most useful one4 ,the removal of the scraped sand from a filter was a matter of a good many hours' work1 under the most favorable conditions4 ,to get the filters quickly into service again1 the dirty sand in a number of them was simply scraped from the surface1 heaped into piles1 and left there2 then the water was turned in1 and the filter was started again4 ,this was done with some hesitation at first for fear the presence of the piles of dirty sand might cause high bacterial counts in the effluents of those filters4 ,no such effect was observed1 however1 the counts being entirely normal throughout4 ,the writer subsequently found the same treatment being applied as an emergency measure at the ,torresdale plant1 in ,philadelphia1 and1 through the courtesy of the ,chief ,engineer of the ,bureau of ,filtration1 was furnished with the bacterial counts through a number of runs made under these conditions1 and there1 too1 the results were entirely normal4 ,there was practically no economy in this method1 as the sand had ultimately to be ejected and washed4 ,the piling up of the sand had the effect of reducing the effective filtering area by a small percentage1 with a corresponding increase in the actual rate of filtration1 but this was of trifling importance4 ,the great benefit derived from the method was the saving of time in getting a filter back into service after scraping1 and in this respect it was very valuable4 ,physical ,theory of ,purification of ,water by ,slow ,sand ,filters4 ,the first and most natural conception of the action of a sand filter is that the removal of impurities is effected by a straining action4 ,this1 of course1 is perfectly true as far as it relates to a large part of the visible impurities4 ,much of this is gross enough to be intercepted and held at the surface of the sand4 ,this very straining action is an accumulative one4 ,after a quantity of suspended matter thus strained out mats itself on the surface of the sand1 it in turn becomes a strainer1 even better adapted than the clean sand surface which supports it for the removal of suspended matter from the water4 ,this1 however1 cannot explain certain features of the purification of water by a layer of sand4 ,the removal of color1 the reduction of nitrates1 and certain other changes in the organic content of the water have for a long time been recognized as due to a bio-chemical action carried on by certain bacteria in the sand4 ,both the straining action and this bio-chemical action are not all-sufficient for the explanation of certain phenomena1 and it has been recognized1 too1 that sedimentation in the pores of the sand played a large part in the purification process in those cases in which it was apparent that the biological agencies were not the chief ones4 ,in the purification of water containing only insignificant quantities of suspended matter1 but a relatively large amount of unstable organic matter1 it will be conceded at once that the chief factor in the purification is the nitrification produced by the bacteria in the upper layers of the sand4 ,on the other hand1 the purification by sand filters of a hypothetical water containing no organic matter1 but only finely-divided mineral matter in suspension1 could take place only by the physical deposition of the particles upon the sand grains4 ,between these two extremes lie all classes of water4 ,in all problems of water purification by filtration through sand1 both these factors--biological action and sedimentation--play their parts1 assisting and supplementing each other1 the relative importance of one factor or the other depending on the place of the particular water in question on the scale between the two extreme conditions just mentioned4 ,in ,mr4 ,hazen's paper on ,sedimentation#a there is an interesting development of the theory of the removal of suspended matter by sedimentation in the pores of a layer of sand4 ,the factors influencing this removal are the rate of filtration1 the effective size of the sand1 and the temperature of the water4 ,for the conditions at the ,washington plant1 it may be assumed that the first two of these factors are constant4 ,the third factor1 however1 varies through wide limits1 and the observations on the turbidity removal1 and on the different phases of the filter operation of which the turbidity of the water is a factor under varying temperature conditions1 together with the known relations between hydraulic values and temperatures of water1 furnished good substantiative evidence that this highly-induced sedimentation may be a considerable factor in the purification of the water as effected at this plant4 ,this temperature relation1 briefly stated1 is as follows3 ,for particles of a size so small that the viscosity of the water is the controlling factor in determining the velocity of their subsidence in still water1 that velocity will vary directly as 7,t #aj7 _/ #fj1 in which ,t is the temperature1 in degrees1 ,fahrenheit4 ,that is1 when the temperature of the water is between #gj deg4 and #hj deg4 ,fahr41 a particle will settle with twice the velocity it would have if the water were near the freezing point4 ,footnote #a3 ,transactions1 ,am4 ,soc4 ,c4 ,e41 ,vol4 ,,liii1 p4 #ei4 ,the layer of sand in a slow sand filter may be considered as a very great number of small sedimentation basins communicating one with another1 not in the manner of basins connected in series1 but rather1 as ,mr4 ,hazen has expressed it1 as a long series of compartments connected at one side only with a passageway in which a current is maintained4 ,in any section of the sand layer there are areas through which the water passes with a velocity much greater than its mean velocity through the total area of voids1 while there are other areas in which the velocity is very much less1 perhaps in an almost quiescent state from time to time1 greatly favoring the deposition of particles1 but with a gentle intermittent circulation1 displacing the settled or partly-settled water and supplying from the main currents water containing more suspended matter particles to be removed4 ,there is thus a considerable percentage of the total volume of voids in which the water is subjected to very favorable conditions for sedimentation1 almost perfect stillness and an exceedingly small distance for a particle to settle before it strikes bottom on the surface of a grain of sand4 ,if sedimentation were the predominating factor in the purification of the water1 we would then expect to find the following phenomena in the operation of the filters3 ,a more rapid deposition of a given amount of sediment under summer temperature conditions than under winter1 as the water passes through the sand1 and therefore1 for the former condition of higher temperature3 7a7 ,a greater concentration of this turbidity-producing material in the top layer of sand1 or1 in other words1 a thinner sand layer to be removed in scraping if all the dirty sand is removed2 7b7 ,because of the greater concentration1 a greater rate of ,increase of the loss of head1 and consequently shorter periods of service between scrapings2 7c7 ,a higher limit for turbidity in the water applied to the filter to produce a given turbidity in the effluent4 ,table #cj--,service ,periods and ,scraping ,depths for ,runs ,ending ,in ,various ,months2 ,covering ,entire ,period1 ,october #ast1 #aije1 ,to ,march #ast1 #aijg4 ,average ,average ,mean ,number period of depth of sand temperature1 ,month4 of service removed1 in in degrees1 filters4 in days4 inches4 ,fahrenheit4 ---------------------------------------- ------------------ ,january #ac #ge #b4ji #ci ,february #f #ih #b4df #cg ,march #e #acj #b4ff #da ,april #h #adi #b4if #ec ,may #g #acj #b4hj #fg ,june #aa #abd #b4ce #gg ,july #ag #gj #b4ab #ha ,august #b #di #a4ih #hj ,september #e #gc #b4dh #gf ,october #cg #gj #a4ef #fd ,november #bj #db #j4ha #di ,december #ad #eg #j4id #dj ,the operation of this plant during the first year and a half offered an excellent opportunity for the study of sedimentation in the sand1 and the data in ,table #cj are presented to show that certain of the phenomena of filter operation observed during this period seem to be fairly explicable by the physical theory of purification4 ,these data are given only for the period of operation before the summer of #aijg4 ,at that time the experiments in filter cleaning already described were begun4 ,before that time1 whenever a filter had been cleaned1 all the discolored sand had been removed1 leaving for the following run a new sand surface substantially in the perfect condition of a newly-constructed filter4 ,after that time the experimental methods of cleaning1 and the new routine adopted as a result thereof1 interfered with the tracing of the evidence as clearly as during the earlier periods4 ,illustration3 ,figure #ad--,periods of ,service and ,depths of ,scraping for ,runs ,ending in ,various ,months ,covering ,entire ,period ,oct4 #a1 #aije1 to ,mar4 #a #aijg4 ,table #cj and the corresponding diagram1 ,figure #ad1 show the general variations in the length of runs and depth of penetration1 with the seasonal temperature changes4 ,the increase in length of runs and quantity of sand removed under low temperature conditions is very marked4 ,there is1 however1 a secondary maximum which appears1 as the diagram shows1 where a minimum for the year would be expected4 ,this may have been an irregularity occurring this one year1 which will not appear in the average of several years1 and caused by some factor which has escaped observation4 ,a careful analysis of the data at hand fails to show any explanation for it4 ,it may exist in some of the little-understood biological actions which have their maximum effect under warm-water conditions1 or it may be due--in some obscure way--to the liberation of air under the surface of the sand1 accumulating with pressure enough to break the surface at innumerable points1 thereby reducing the loss of head and extending the period of service4 ,some evidence was observed pointing to this explanation1 but it was never conclusively proven4 ,the general effect of temperature changes on the rapidity of removal of the sediment and its consequent concentration in the sand layer1 however1 seems plainly evident4 ,in corroboration of the third point mentioned in the theoretical consideration of turbidity removal in the filters1 the daily turbidities of the filtered water have been classified and summarized for different turbidities in the applied water1 and also for different temperatures4 ,the average turbidities thus obtained are given in ,table #ca4 ,table #ca--,turbidity in ,filtered ,water at ,different ,temperatures ,produced by ,given ,turbidity in ,applied ,water4 ,turbidity of ,temperature1 in ,degrees1 ,fahrenheit4 applied ---------------------------------------- ----- water4 #dj #dj - #ej #ej - #fj #fj - #gj #gj ---------------------------------------- --------------- #bj #a4h #a4c #a4b #a4e #a4g #bj-dj #d4h #e4j #c4e #c4j #b4f #dj-fj #g4i #f4i #e4d 444 #c4g #fj-hj #aj4g #g4g 444 444 #e4d #hj-ajj #aa4c 444 444 444 444 #ajj 444 444 444 444 #ab4ja ,footnote #a3 ,for an average turbidity #aej4 approximately4 ,the influence of the temperature of the water on the turbidity of the effluent is very pronounced4 ,for a temperature of less than #dj deg4 ,fahr4 7actual average temperature about #ce deg471 the turbidity of the filtered water for a given turbidity of the applied water is practically twice as great as for a temperature greater than #gj deg4 7actual average temperature about #ge deg474 ,this fact fits in very nicely with the influence of temperature on sedimentation4 ,referring again to this temperature relation1 as set forth on a previous page1 the hydraulic subsiding value of a particle in water1 of a size so small that viscosity is the controlling factor in its downward velocity1 is approximately twice as great at #ge deg4 as at #ce degrees4 ,we would then expect to find that1 in order to obtain a given turbidity in the filtered water1 a raw water may be applied at #ge deg41 having twice the turbidity of the water applied at #ce deg41 to produce the same turbidity2 and further1 as the turbidity of the filtered water1 for a given temperature condition1 varies quite directly in proportion to the turbidity in the applied water1 it follows that an applied water of given turbidity will produce an effluent at #ce deg4 with a turbidity twice as great as at #ge degrees4 ,this is quite in accordance with the facts obtained in actual operation1 as indicated on the diagram1 ,figure #ae4 ,preliminary ,treatment of the ,water4--,the most striking features of the bacterial results given in ,table #d are1 first1 the uniformly low numbers of bacteria in the filtered water during perhaps #h or #i months of the year1 and the increase in numbers each winter4 ,this is shown clearly in the analysis of bacterial counts in ,table #cb4 ,table #cb--;,classification of ,daily ,bacterial ,counts in the ,filtered-,water ,reservoir ,during the ,period1 ,november #ast1 #aije1 to ,february #ast1 #aijh4 ,bacterial count between3 ,no4 of days4 ,percentage of whole4 ---------------------------------------- ---------------------- #j and #bj per cu4 cm4 #bia #da4j #bj and #dj per #bde #cd4f #dj and #fj per #fc #h4i #fj and #hj per #cj #d4b #hj and #ajj per #bh #d4j #ib4g ---------------------------------------- ---------------------- #ajj and #bjj per #bi #d4a #bjj and #cjj per #ac #a4h #cjj and #ejj per #e #j4g #ejj and #ajjj per #e #j4g #g4c ---------------------------------------- ---------------------- #ajj4j ,the tests for ,bacillus ,coli in ,table #e show results which correspond closely to these1 with this organism detected only infrequently1 except during the periods of high bacteria1 and both of these are parallel to the turbidity variations in the filtered water4 ,these variations follow closely the variations in the turbidity and in the bacterial content of the water applied to the filters4 ,by all standards of excellence1 the sanitary quality of the water during the greater part of the time is beyond criticism4 ,in view of the close parallelism of turbidity and bacterial results in the applied and in the filtered water1 it is entirely logical to conclude that1 if the quality of the applied water could be maintained continually through the winter as good as1 or better than1 it is during the summer1 then the filtered water would be of the perfect sanitary quality desired throughout the entire year4 ,this was all foreseen ten years ago1 when ,messrs4 ,hering1 ,fuller1 and ,hazen recommended auxiliary works for preliminary treatment of the supply1 although1 as the author states1 these works were not provided for in the original construction4 ,as prejudice against the use of a coagulant seemed to be at the bottom of the opposition to the preliminary treatment1 a campaign of education bearing on this point was instituted1 in addition to the systematic studies of different preliminary methods to which the author refers4 ,as a result of the combined efforts of all those interested in promoting this improvement1 an appropriation was finally made for the work in #aiaj4 ,the coagulating plant has since been built1 and the writer is informed that coagulation was tried on a working scale a short time ago during a period of high turbidity4 ,a statement of the results of this treatment on the purification of the water in the reservoir system and in the filter plant would be of great interest4 ,illustration3 ,figure #ae-- ,turbidity in ,applied ,water4 ,hydraulic ,replacing of ,filter ,sand4--,the author has adopted a method of replacing clean sand in the filters which will commend itself to engineers as containing possibilities of economy in operation4 ,the first experiments in the development of this method at the ,washington plant were carried out some three years ago1 while the writer was still there4 ,substantially the same methods were used then as are described in this paper1 but examination of the sand layer by cutting vertically downward through it after re-sanding in this manner showed such a persistent tendency toward the segregation of the coarse material as to hold out rather discouraging promises of success4 ,the greatest degree of separation seemed to be caused by the wash of the stream discharging sand on the surface4 ,it was observed that1 near the point where the velocity of the stream was practically destroyed1 there seemed to be a tendency to scour away the fine sand and leave the coarse material by itself1 and pockets of this kind were found at many points throughout the sand layer4 ,the author states that1 in the recent treatment of the filters by this method1 there has been no apparent tendency for the materials to separate into different sizes1 and it is fortunate if this work can be done in such a manner as to avoid this separation entirely4 ,it may be questioned whether a certain amount of segregation of the materials will make any practical difference in the efficiency of a filter4 ,in all probability this depends on the degree of the segregation1 the quantity of pollution in the water to be filtered1 the rate of filtration1 and the uniformity of methods followed in the operation1 etc4 ,for an applied water as excellent in quality as that of the ,washington ,city ,reservoir during favorable summer conditions1 a considerable degree of segregation might exist without producing any diminution in efficiency4 ,for a badly polluted water1 however1 such as the applied water at this plant during certain winter periods1 or the water of a great many other polluted supplies1 it might be found that even a slight lack of homogeneity in the sand might make an appreciable difference in the results of filtration4 ,as a result of the experiments herein described1 however1 this method may be applied at other plants where conditions seem to warrant it1 with a largely increased measure of confidence2 although1 as in the case of the adoption of any new or radical departure1 that confidence must not be permitted to foster contempt of the old and tried methods1 but its operation must be watched with the utmost caution1 until long experience shall have demonstrated its perfect suitability and defined its limitations4 ,e4 ,d4 ,hardy1 ,m4 ,am4 ,soc4 ,c4 ,e4 7by letter74--,it was not the writer's original intention to enter into a discussion of either the theory of water purification or of the experimental work on sand handling1 but simply to present the main results of operation largely in tabular form4 ,he is gratified1 however1 to have these sides of the question so ably brought out in ,mr4 ,longley's discussion4 ,mr4 ,hazen referred to the inferior efficiencies of the experimental filters for rate studies 7as shown in ,table #bj7 in the removal of the ,b4 ,coli from the water tested4 ,this inferiority is really less than the figures in the table would indicate1 as the tests for the experimental filters were presumptive only 7as shown by the note at the foot of ,table #bj71 while those for the main filters were carried through all the confirmatory steps4 ,from experiments#a made by ,messrs4 ,longley and ,baton in the writer's office1 it would seem reasonable to assume that about one-half of the positive results1 would have been eliminated had the confirmatory steps been taken4 ,in other words1 the figures showing the number of positive tests for ,b4 ,coli in ,table #bj should be divided by two when comparing them with corresponding ones for the main filters4 ,footnote #a3 ,published in the ,journal of ,infectious ,diseases1 ,vol4 #d1 ,no4 #c1 ,june1 #aijg4 ,mr4 ,knowles seems somewhat apprehensive regarding the methods described in the paper of restoring the capacity of the filters by raking1 and replacing sand by the hydraulic method1 and yet1 from ,mr4 ,johnson's discussion1 it would seem that the practice of raking filters between scrapings had recently been adopted at the ,pittsburg plant4 ,before the practice of raking was finally adopted as a part of the routine filter operation1 the subject was given a great deal of thought and study1 as may be seen by referring to ,mr4 ,longley's discussion4 ,the re-sanding has been done by the hydraulic method1 for nearly two years1 and1 as far as the writer is able to judge1 this method has been more economical and also more satisfactory in every way than the old one4 ,as ,mr4 ,hazen states1 this does not prove that the hydraulic method would be as satisfactory for other filter plants and other grades of sand4 ,the elevated sand bins at the ,washington plant fit in well with this scheme1 and save the expense of one shoveling of the sand2 and the low uniformity coefficient of the sand is favorable in decreasing its tendency to separate into pockets or strata of coarse and fine sand4 ,the method of washing is also well adapted to this method of re-sanding1 as the sand is made very clean in its passage through the washers and storage bins4 ,the hydraulic method of replacing sand tends to make it cleaner still1 because any clay which may be left in the sand is constantly being carried away over the weir and out of the bed1 to the sewer4 ,sand replaced by the hydraulic method is much more compact than when replaced by other methods1 and consequently the depth of penetration of mud in a filter thus re-sanded is less4 ,careful tests of the effluents from filters which have been re-sanded by the two methods have invariably shown the superiority of the hydraulic method4 ,the experiment of replacing sand by water1 referred to by ,mr4 ,longley1 was not considered a success at the time1 and the method was abandoned for about a year4 ,at that time an attempt was made to complete the re-sanding of a filter which had been nearly completed by the old method4 ,the precaution of filling the filter with water was not taken1 nor was any special device used for distributing the sand4 ,when this method was again taken up1 various experiments were tried before the present method was adopted4 ,mr4 ,whipple's remarks on the results from the operation of filters under winter conditions are very interesting1 and1 considering his standing as an authority in such matters1 they are worth careful consideration4 ,in the operation of the ,washington plant1 it has always been noticeable that the results were much poorer in winter than in summer4 ,in fact1 nearly all the unsatisfactory water which has been delivered to the city mains has been supplied during the winter months4 ,on the other hand1 the typhoid death rate has always been comparatively low in cold weather4 ,these facts would seem to indicate that the water supply was not responsible for the typhoid conditions4