,transcriber ,note3 ,text emphasis is denoted as ,bold and ,italics4 ,fractions are represented as #a-b_/c4 ,,sewage and ,,garbage ,,disposal on the ,,farm ,illustration ,,farmers' ,,bulletin ,no4 #aiej ,u4,s4 ,,department ,,of ,,agriculture ,this ,bulletin is a guide to up to-date methods for the sanitary disposal of sewage and other household and farm wastes4 ,it tells how to construct satisfactory sanitary facilities and how to maintain them and gives special attention to the questions on sanitation asked most frequently by farm people4 ,solutions to all problems cannot be given here1 and often advice must be sought from local sanitary officials4 ,many county and ,state health departments furnish advice and copies of local regulations and sometimes provide inspection service4 ,where there are no specific local requirements1 this bulletin may be accepted as a guide to safe practice4 ,issued ,march #aidd ,washington1 ,d4 ,c4 ,revised ,june #aidf ,,sewage ,,and ,,garbage ,,disposal ,,on ,,the ,,farm ,by ,j4 ,w4 ,rockey1 assistant agricultural engineer1#a and ,j4 ,w4 ,simons1 associate agricultural engineer1 ,division of ,farm ,buildings and ,rural ,housing1 ,bureau of ,plant ,industry1 ,soils1 and ,agricultural ,engineering1 ,agricultural ,research ,administration #a ,the senior author prepared the preliminary draft1 and the junior author completed the bulletin4 ,contents ,page ,characteristics of sewage #a ,protection of water sources from household wastes #b ,septic-tank systems #b ,operation of a septic tank system #b ,selecting the site #d ,the house sewer #d ,the septic tank #h ,building a concrete tank #aa ,the effluent sewer #ac ,the disposal field #ac ,disposal methods in tight or wet soils #ad ,care and maintenance of septic tanks #ag ,effect of drain solvents and other materials #ag ,protection against freezing #ag ,septic-tank troubles #ah ,grease traps #ah ,disposal of drainage from fixtures other than toilets #ai ,cesspools #bj ,privies #ba ,care1 and maintenance #bb ,chemical closets #bd ,disposal of garbage and trash #be ,,to ,,insure healthful living1 domestic wastes must be disposed of4 ,primitive wanderers and too often present-day tourists deposit their wastes promiscuously and move on when the surroundings become foul4 ,this is impractical in built-up communities4 ,therefore1 in most cities and in some rural areas sanitary codes regulate the disposal of wastes4 ,,characteristics ,,of ,,sewage ,household sewage ordinarily consists principally of human excrement1 toilet paper1 garbage1 dish water1 and other wash water from the various plumbing fixtures and floor drains4 ,many kinds of bacteria1 at times disease-producing ones1 are contained in the discharges from the human body4 ,epidemics of typhoid fever1 dysentery1 diarrhea1 cholera1 and other water-borne diseases may result from the pollution of the water supply with sewage4 ,pollution is carried by water moving underground1 as well as by water flowing on the surface4 ,this is especially true in limestone regions1 where underground channels and rock crevices permit water to flow for considerable distances with little filtering action4 ,sewage used for fertilizing or irrigating crops#b may contaminate vegetables or the udders of cows and thus spread disease4 ,anthrax1 cholera1 and parasitic worms may be present in the surface drainage from fields and barn lots4 ,it is wise to regard all sewage as dangerous and to dispose of it promptly in a sanitary manner1 so that disease germs will not pollute the water supplies or be spread by flies1 animals1 or man4 #b ,this subject is discussed at length in ,technical ,bulletin #fge1 ,sewage ,irrigation as ,practiced in the ,western ,states4 ,,protection ,,of ,,water ,,sources ,,from ,,household ,,wastes ,under most farm conditions a safe place for the disposal of wastes is in the upper #c-;foot layer of soil1 where the action of bacteria tends to render it harmless4 ,tile disposal fields1 such as are used with septic tanks1 and earth-pit privies accomplish this if the water table remains several feet below the surface and if the location is remote from water supplies4 ,cesspools and other types of pits do not ordinarily confine contamination to their immediate vicinity and are not recommended except for special conditions4 ,sewage or other wastes discharged into abandoned wells or other pits that reach to the water table or below it are almost certain to contaminate the ground water4 ,it is generally poor practice1 and often illegal1 to discharge wastes into surface streams4 ,streams do not necessarily purify themselves in #ej feet1 #ajj feet1 or some other stated distance1 as is commonly believed4 ,they do tend to purify themselves over long distances through the action of sunlight1 aeration1 and other factors but may not be safe for domestic use for many miles below the source of pollution4 ,clear1 sparkling water is not always safe drinking water4 ,streams in agricultural communities are subject to many sources of pollution and they are likely to become more contaminated as they merge into larger streams4 ,,septic-,,tank ,,systems ,septic-tank systems1 if installed and maintained properly1 provide the most sanitary method of sewage disposal for farmhouses equipped with running water4 ,ground water or rock close to the surface1 lack of sufficient fall for the sewage to flow by gravity1 and too small an absorption area for the effluent limit the satisfactory operation of a septic tank4 ,when these conditions exist1 special advice should be sought from a competent local sanitary authority4 ,adverse soil conditions can be overcome if sufficient fall and space are available4 ,the five essential parts 7fig4 #a7 of a septic-tank system are 7#a7 the house sewer2 7#b7 the septic tank2 7#c7 the effluent sewer2 7#d7 the distribution box2 and 7#e7 the disposal field4 ,in special cases a grease trap 7see fig4 #aa1 p4 #ai7 is added4 ,to facilitate inspection and repairs it is good practice to keep in the house a chart showing the location of the tank and other parts of the system4 ,a septic tank does not necessarily purify the sewage1 eliminate odor1 or destroy all solid matter4 ,its purpose is to condition the sewage or domestic waste by bacterial action1 so that it can be disposed of in a more satisfactory manner4 ,illustration3 ,figure #a4--;,a septic-tank system4 ,,operation ,,of ,a ,,septic-,,tank ,,system ,in a septic-tank system the sewage flows by gravity from the farmhouse through the sewer into the tank1 where it should remain at least #bd hours4 ,while passing through the tank the solids are acted upon by anaerobic bacteria1 which work only in the dark and where there is little air4 ,the heavy particles settle to the bottom as sludge1 the lighter particles float as scum1 and the remainder passes out of the tank through the effluent sewer to the disposal field4 ,the gas released in the process escapes through a vent provided either in the ,t to the house sewer or the effluent sewer4 ,a tank that is too small may fill up with solids in a short while1 because sufficient time is not allowed for breaking them down by fermentation1 or the sewage may be pushed right through into the disposal field and clog it4 ,the effluent may contain even more disease germs than the original sewage1 and though it may be as clear as spring water it is far from pure and may cause foul odors if discharged or allowed to pool on the surface of the ground4 ,the final disposition of the effluent into the upper layer of the soil exposes it to the action of aerobic bacteria4 ,these bacteria1 unlike those in the tank1 need air and cannot work in saturated soil or live much more than #c feet below the surface of the ground4 ,the living earth1 or upper stratum1 teems with these bacteria1 which convert the dangerous sewage and disease germs into harmless matter and thus tend to purify the effluent if it remains long enough in the top layers of soil before seeping into the subsoil and thence to the ground water4 ,effluent discharged deep in the soil does not receive the benefit of this purifying action4 ,several types of septic tanks are in common use4 ,the one described in this bulletin is the single-chamber type1 which can be built with or without siphon4 ,this should meet all average farm needs where there are not more than #af members in the household4 ,it would be advisable to consult the authorities of the ,state agricultural college or local health department as to their recommendations because frequently local conditions and larger establishments require special installations4 ,,selecting ,,the ,,site ,first install the tile disposal field where there will be least danger of polluting water supplies1 at least #ajj feet from water sources if possible and always at a lower surface elevation4 ,this is of greatest importance4 ,even though selecting a more distant location would result in greater initial cost1 it would be a good investment as protection against diseases that might result from pollution of water sources4 ,the site should slope away from the house and away from the source of water4 ,gentle unshaded slopes free of trees or shrubbery are best4 ,root-free locations are important because the open-jointed tile cannot be rootproofed4 ,porous1 well-drained1 gravelly1 or sandy soil allows greater purification4 ,do not have the disposal field in vegetable gardens1 under roadways1 in swampy land1 in muck soils1 or in areas having rock substrata sloping toward the water supply4 ,allow sufficient area1 where available1 to enlarge the field later if needed4 ,the septic tank may be close to the house1 but a more distant site would reduce the likelihood of odors if leakage occurs4 ,the tank should also be kept #ej feet or more from any source of water supply and at a lower elevation4 ,it should not be placed under driveways1 pavements1 or flower beds1 as these would make it not readily accessible for periodic inspection4 ,care should be taken to insure that surface drainage from the area around the tank will not reach the vicinity of the water supply4 ,,the ,,house ,,sewer ,material ,vitrified salt-glazed clay or well-made concrete sewer pipe and cast-iron soil pipe are the standard materials for house sewers on farms4 ,asphalt-impregnated fiber pipe1 of a type designed especially for house sewers1 appears to be satisfactory for this purpose4 ,cast-iron soil pipe with leaded joints should be used when the sewer is within #ej feet of a well or suction line from a well1 within #aj feet of any drinking-water supply line under pressure1 within #e feet of basement foundations1 or when laid beneath driveways with less than #c feet of earth covering the pipes4 ,when within #ae feet of large trees or shrubs1 the sewers should have root-tight joints4 ,size ,for house sewers1 #d- and #f-;inch pipes are generally used4 ,where a #d-;inch pipe is used1 cast-iron is commonly recommended4 ,grades with little fall require larger pipes4 ,the large sizes are also less liable to become clogged4 ,clay pipe is made in pieces #b or #b-a_/b feet long1 whereas fiber-pipe sections are #d feet long and cast-iron pipe #e feet long1 so that there are fewer joints4 ,the minimum number of joints is desirable1 as there is less danger of stoppage4 ,alinement ,run the house sewer in a straight line and avoid bends whenever possible4 ,slight changes in direction may be made with one-sixteenth or one-eighth bend fittings4 ,for sharper changes of direction a manhole or distribution box may be used4 ,changes in direction of more than #de are not recommended unless a manhole is provided4 ,clean-outs are desirable within #e feet of the septic tank where tanks are placed more than #bj feet from the building and the sewer line is not buried deeper than #d feet4 ,establishing ,line and ,grade ,the trench for laying the sewer is usually dug after the septic-tank excavation has been completed and the elevation of the tank inlet determined4 ,a simple method of setting guides for the excavation is illustrated in figure #b4 ,digging the ,trench ,start digging the trench at the tank end1 so that rain or seepage will have an outlet4 ,rounding the bottom of the trench to the shape of the pipe and hollowing out basins for the bell ends allows the pipe to rest firmly throughout its full length1 permits full calking of joints1 and relieves the strain on them4 ,laying the ,pipe ,begin laying the pipe at the tank with the bell end uphill4 ,joints in clay-tile pipe are commonly made with portland cement mortar or grout4 ,where root-proof joints are essential1 sulfur-sand compounds may be used or copper rings provided and used with cement-mortar joints4 ,asphalt-mastic compounds1 however1 are more satisfactory4 ,for cast-iron soil pipe1 lead is the standard joint material4 ,after the hub is pushed into the bell1 oakum 7or old hemp rope7 is packed with a calking iron or a piece of wood 7fig4 #c1 ,a47 solidly and evenly in the joint to a depth of about half an inch to center the hub end in the bell and to keep the joint filler from getting inside the pipe4 ,oil1 grease1 or dirt on the joint surfaces should be removed1 as it will prevent joint material from sticking4 ,figure #c shows the different jointing methods4 ,illustration3 ,figure #b4--;,establishing grade for sewer4 ,a1 #b- by #d-;inch stakes are set each side of the trench at convenient distances a1 b1 c1 and d4 ,then a board is nailed horizontally on the stakes at d at a convenient height above the bottom of the trench1 that is1 the bottom of the sewer leaving the house4 ,a board is nailed likewise to the stakes at a the same height above the inlet to the tank that d is above the bottom of the trench4 ,similarly1 boards are set at b and c by sighting from a to d so the tops of the intermediate boards will be in line4 ,b1 ,the exact grade of the sewer is obtained by measuring from the grade cord with the #a- by #a-;inch stick1 shown in detail4 ,the length of the stick must equal the height of the board above sewer at d4 ,bituminous1 sulfur-sand1 lead1 and other commercial joint compounds are poured while hot into the joint from a ladle 7fig4 #c1 ,f71 and when the work is well done they form a joint that is practically root-proof4 ,they are more expensive than cement mortar4 ,for molding hot compounds1 a clay dike1 or funnel1 built about #c inches high around the triangular opening at the top of the jointer greatly aids in the rapid and complete filling of the joint space4 ,a hot joint must be poured continuously1 otherwise a seam may develop between successive pourings4 ,bituminous compounds make a slightly elastic joint4 ,a joint in #d-;inch pipe requires about #c_/h to #a_/b pound of compound and in #f-;inch pipe about #a to #a-a_/b pounds4 ,sulfur-sand joints are hard and inelastic4 ,the compound is made by mixing together equal volumes of ordinary powdered sulfur and very fine clean sand1 preferably the finest quicksand1 and then heating the mixture until the sulfur melts4 ,a #d-;inch joint takes about #c_/d pound and a #f-;inch joint about #a-g_/h pounds of the mixture4 ,commercial sulfur-joint compounds also are available4 ,illustration3 ,figure #c4--;,jointing sewer pipe4 ,a1 ,using calking iron to force packing into joint4 ,b1 ,making joint with #a3b portland cement mortar4 ,use only enough water to dampen the mix4 ,recalk after half an hour1 to close shrinkage cracks4 ,c1 ,the completed joint4 ,wrap finished joint with cloth and keep dampened1 to aid curing4 ,d1 ,joint made by pouring #a3a ,portland cement grout of creamy consistency into a form4 ,this type of joint is not feasible unless the metal forms shown are available4 ,e1 ,use of asbestos runner clamped around pipe1 for pouring hot joint4 ,f1 ,clay roll used in place of asbestos runner4 ,g1 ,a completed bituminous joint4 ,h1 ,use of swab1 to remove any joint material forced through to inside of pipe4 ,soft pig lead or old scrap lead is suitable for lead joints on cast-iron pipe4 ,about #c_/d pound per inch of pipe diameter is generally required for each joint4 ,the lead is hot enough to pour when it begins to char the paddle used to skim off the impurities4 ,when it cools it must be calked tightly to take up shrinkage4 ,the calking should be uniform around the entire joint and should stop when the lead is tight4 ,heavy pounding or continued calking may crack the bell of the pipe4 ,it is easier to get good1 joints when the pipe is in a vertical position4 ,therefore1 two lengths of pipe are frequently joined and are then laid as a single unit in the trench4 ,in using terra cotta pipe1 this procedure may be followed only when the joint is made with a mastic compound4 ,cement-mortar joints cannot be used in such cases4 ,before filling the trench1 the sewer should be tested to detect possible leaks4 ,earth free from rubbish and large stones should then be tamped around and about #a foot above the pipe4 ,,the ,,septic ,,tank ,flow ,through the ,tank ,slow1 undisturbed flow through the tank is necessary for the separation of solids and liquids and for bacterial action4 ,submerged inlets and outlets or baffle boards reduce disturbance4 ,a submerged outlet prevents scum from passing out with the effluent4 ,the single-chamber tank without a siphon1 shown in figure #d1 is easy to build1 inexpensive1 and entirely satisfactory in most instances4 ,in very tight soils or for large installations a siphon and sometimes two chambers are advisable4 ,size ,the tank should be large enough to retain the sewage at least #bd hours4 ,the size should be determined by the largest number of persons that may live in the house1 rather than by the number actually living there at the time the tank is built4 ,the additional cost of a large tank over a small one is relatively little4 ,if there is any question as to which of two sizes should be built1 it is wise to choose the larger4 ,the dimensions recommended in the table in figure #d are based on an average production of #ej gallons of sewage per person per day4 ,unusually large quantities of sewage call for a tank of large capacity4 ,in village and suburban homes where there is less food preparation than on farms and where the number of persons is more or less fixed1 slightly smaller sizes will serve4 ,in no case should the capacity of the tank below the flow line be less than #ejj gallons4 ,a tank length of two to three times the width should be maintained1 and it is advisable to provide a depth of at least #d feet below the flow line4 ,allow about #a foot of freeboard1 or air space1 above the flow line for the accumulation of gases4 ,this space is generally vented through the soil stack of the house4 ,a siphon 7fig4 #e7 with a dosing chamber is not considered necessary for a farm septic tank except for large installations 7#a1jjj gallons or more71 for those in tight soils1 and where the disposal field is limited4 ,illustration ---------------------------------------- ----------------------------------- ,,capacities1 ,,dimensions1 ,,and ,,concrete ,,materials ,,for ,,septic ,,tanks ,,serving ,,individual ,,dwellings ---------------------------------------- -------------------------------- ,maximum ,liquid ,recommended inside dimensions ,materials for concrete number ofcapacity----------------------------- #a3b-a_/b3d mix persons of tank ,width,length,liquid,total --------------------- served in depth depth,cement,sand ,gravel gallons sacks cubic cubic yards yards ---------------------------------------- --------------------------- #d or less #ejj #c'-j #f'-j #d'-j #e'-j #af #a-a_/b #b-a_/b ---------------------------------------- --------------------------- #f #fjj #c'-j #g'-j #d'-j #e'-j #ag #a-c_/d #b-c_/d ---------------------------------------- --------------------------- #h #gej #c'-f #g'-f #d'-j #e'-j #ai #b #c ---------------------------------------- --------------------------- #aj #ijj #c'-f #h'-f #d'-j #e'-j #ba #b-a_/d #c-a_/d ---------------------------------------- --------------------------- #ab #aajj #d'-j #e'-f #d'-f #e'-f #bd #b-a_/d #c-a_/b ---------------------------------------- --------------------------- #ad #abjj #d'-j #e'-j #d'-f #e'-f #be #b-a_/b #c-c_/d ---------------------------------------- --------------------------- #af #aejj #d'-f #aj'-j #d'-f #e'-f #bh #b-c_/d #d-a_/d ---------------------------------------- --------------------------- ,figure #d4--,single-chamber septic tank4 ,note alternate use of baffle boards where sanitary tees are omitted at inlet and outlet4 ,the siphon provides intermittent discharge of effluent1 which allows time for the disposal area to rest and aerate between discharges4 ,this is more important where the discharge is nearly continuous than in small installations4 ,the frequency and volume of the discharge into the tile field are controlled by the sizes of the siphon and the dosage chamber4 ,the dealer should be informed of the size of the tank and the number of persons in the household1 in order that he may furnish the proper unit4 ,a #c- or #d-;inch siphon will be adequate for almost any farmhouse installation4 ,construction ,most septic tanks are built of concrete cast in place1 since in this way there is a minimum possibility of cracks developing4 ,concrete blocks1 however 7not cinder blocks71 stone1 brick1 or structural tile are sometimes used4 ,prefabricated commercial tanks of concrete and various other materials also are available4 ,illustration ---------------------------------------- ---------------------- ,,siphon ---------------------------------------- --------------------- ,diameter of siphon ,clearance under bell ,a - #c or #d ,e - #b ---------------------------------------- --------------------- ,diameter of bell ,distance across ,u-trap ,b - #ajor #ab ,f - #aj or #ab ---------------------------------------- --------------------- ,bottom of outlet ,bottom of outlet to discharge line to bottom of ,u-trap ,c - #bj-a_/b to #be-c_/d ,g - #ab or #ac ---------------------------------------- --------------------- ,drawing depth ,height above floor ,d - #ac to #ag ,h - #g-a_/dto #aa-c_/d ---------------------------------------- --------------------- ,,dimensions ,,of ,,dosing ,,chamber ---------------------------------------- ------------------- ,number of ,depth below persons served discharge line#c ,width#d ,length ---------------------------------------- ------------------- #d or less #af-a_/d to #bj-a_/d #c'-j #f'-j ---------------------------------------- ------------------- #f #c'-j #g'-j ---------------------------------------- ------------------- #h #c'-f #g'-f ---------------------------------------- ------------------- #aj #c'-f #h'-f ---------------------------------------- ------------------- #ab #d'-j #h'-f ---------------------------------------- ------------------- #ad #d'-j #i'-j ---------------------------------------- ------------------- #af #d'-f #aj'-j ---------------------------------------- ------------------- #c ,depending upon depth ,c of siphon4 #d ,same as single chamber tank fig4 #d4 ,figure #e4--,typical design for a concrete septic tank with a dosing chamber and a siphon4 ,masonry units should be laid in full beds of #a3c cement mortar and the walls and floor plastered with at least a #a_/b-;inch coat of #a3b mortar4 ,cells of concrete blocks and tile must be filled with concrete4 ,masonry walls are generally #h inches thick1 and care must be taken to follow inside dimensions given for concrete tanks4 ,directions for laying structural tile1 brick1 and concrete blocks can be obtained from dealers or trade associations4 ,commercial tanks are suitable if they embody the essential features given in this bulletin4 ,capacities should be as recommended in figure #d for concrete tanks4 ,proper installation and periodic servicing also are essential4 ,tanks badly damaged in handling should not be used4 ,rapid corrosion of steel tanks will result if the asphalt coating is impaired4 ,minor defects in precast masonry tanks may often be overcome by plastering the interior with cement mortar4 ,,building ,a ,,concrete ,,tank#e #e ,for information on making and placing concrete1 see ,farmers' ,bulletin #aggb1 ,use of ,concrete on the ,farm4 ,a convenient method of assuring correct location of the tank is to build a frame as shown in figure #f4 ,care is necessary to aline it with the center line of the inlet and outlet and to level it so that the distance from the bottom of the #b by #d's on the form to the lower edge of the inlet hole in the form will permit it to be set at the grade of the house sewer4 ,this frame is used to support the form for the tank4 ,to avoid caving the edges1 drive the stakes supporting the frame before beginning the excavation4 ,the lumber in the frame can be used later to make part of the tank baffles4 ,illustration3 ,figure #f4--,method of outlining a septic-tank excavation on the ground surface4 ,figure #g shows how an inside form can be built and hung in place4 ,the inlet and outlet tees should be carefully set and tied in place before the concrete is poured4 ,a single length of pipe should be joined to the tee1 so that the two can be set in the form as one unit4 ,in most cases the earth walls of the excavations will serve as the outside forms unless the soil is sandy or gravelly and the excavation is deeper than #e feet4 ,if outside forms are used1 space must also be provided for them4 ,forms should be constructed before the excavation is made and the tank built as soon as practical1 to avoid warping of forms and caving of earth walls4 ,illustration3 ,figure #g4--;,inside form hung in place for single-chamber septic tank1 also a form for casting concrete-slab cover in sections4 ,county agricultural agents1 local health departments1 building-material dealers1 and other agencies often have forms that may be borrowed or rented4 ,,the ,,effluent ,,sewer ,the effluent sewer should be constructed in similar manner and of the same materials as the house sewer and on a slope of #a_/h inch to #a foot4 ,this line1 however1 may be laid of terra-cotta pipe1 as cast-iron is not considered necessary except in unusual cases4 ,this line should always terminate in a distribution box from which the tile lines of the disposal field lead away4 ,for steep slopes the arrangement shown in figure #i 7p4 #ae7 is practical4 ,joints must be of root-tight construction if the sewer is in the vicinity of trees or shrubs4 ,the length of the sewer depends upon the distance from the tank to a safe site for the disposal field4 ,,the ,,disposal ,,field ,correct installation of the disposal field is of great importance for proper functioning of the septic tank4 ,therefore1 the width1 depth1 and spacing of the tile trenches must be carefully selected4 ,line of #d-;inch1 open- jointed1 agricultural drain tile laid in shallow trenches are ordinarily used4 ,perforated fiber drain pipes also may be used and are obtainable in #d-;foot lengths4 ,a distribution box with an inlet for the effluent sewer and an outlet for each individual run of disposal tile is the best means of dividing the flow4 ,the outlet serving a large or double disposal field may be alternately opened and closed by means of a sewage switch that permits half the disposal field to work and rest alternately several weeks4 ,a switch is especially helpful in tight soils but should not be provided unless proper maintenance is assured1 so that a portion of the disposal field will not be left to handle the entire load of the system for an indefinite period4 ,there are many variations of boxes1 but figure #h shows a practical type4 ,illustration3 ,figure #h4--,typical distribution box4 ,shallow ,tile ,lines ,the disposal tile should not be more than #ah to #bd inches below the surface1 and where the ground-water level rises to the bottom of the trench special underdrains1 described on page #af1 are necessary4 ,special provisions must also be made where tight soils are encountered4 ,these methods are described in the section entitled ,disposal methods in tight or wet soils4 ,the table in figure #i1 together with the information given in table #a1 below1 may be used for estimating the number of tiles needed in any particular soil type4 ,if there is any doubt about this requirement1 a percolation test should be made in the disposal field1 as follows3 ,dig a hole #a-;foot square and to the depth at which the tile is to be laid4 ,this depth in most instances will be about #bd inches and should not exceed #cf inches4 ,fill the hole with water to a depth of #f inches and observe the time required for the water to seep away2 divide by #f to get the average time for the water to fall #a inch4 ,the test should be repeated at three or four different points in the disposal field and the average time noted for all tests used4 ,the data in table #a can then be used to determine the number of tiles needed4 ,where #a hour is required for the water to fall #a inch the soil is totally unsuitable1 and another site should be selected4 ,soil conditions at the time of the test may vary from year-round average conditions1 and this factor must be taken into account4 ,if the soil appears exceptionally dry1 greater depths of water may be used or the test repeated in the same hole4 ,in no case should tests be made in filled or frozen ground4 ,where fissured rock formations are encountered1 advice should be sought from sanitation specialists4 ,table #a4--;,determining tile-disposal field requirements from percolation tests#f ---------------------------------------- --------------------------- ,minutes ,effective absorption ,minutes ,effective absorption required area required1 per required area required1 per for water to person1 in bottom for water to person1 in bottom fall #a inch of disposal trenches fall #a inch of disposal trenches ---------------------------------------- --------------------------- ,square feet ,square feet #b or less #bf #aj #eb #cj #ae #fc #cf #cj #ij #dj #fjg #abj ---------------------------------------- --------------------------- #f ,a minimum of #aej square feet should be provided1 equal to #ajj feet of #ah-;inch trench4 #g ,if more than #fj minutes1 use special design with seepage pits or sand-filter trenches4 ,figure #i suggests methods of arranging the tiles in disposal fields under varying conditions and the length of tiles needed4 ,illustration3 ,figure #i4--;,arrangements for tile-disposal fields1 method of laying tile1 and length of tiles needed4 ,,size ,,and ,,minimum ,,spacing ,,requirements ,,for ,,disposal ,,trenches ---------------------------------------- -------------- ,,trench ,,trench ,,effective ,,absorption ,,tile ,,lines ,,width-,w ,,depth-,d ,,area ,,in ,,square ,,feet ,,spacing-,s ,,in ,,inches ,,in ,,inches ,,per ,,lineal ,,foot ,,in ,,feet ---------------------------------------- -------------- #ah #ah to #cj #a4e #f4j #bd #ah to #cj #b4j #f4j #cj #ah to #cf #b4e #g4e #cf #bd to #cf #c4j #i4j ---------------------------------------- -------------- ,wider spacing of the lines desirable where available area permits ,,disposal-,,tile ,,trench ,disposal-tile lines--,maximum length for each line #ajj feet4 ,all lines to be equal in length4 ,disposal-tile lines to slope #b to #d per #ajj feet1 not over #f4 ,sewer-tile lines to slope #a_/h to #a_/d per foot4 ,,disposal ,,methods ,,in ,,tight ,,or ,,wet ,,soils ,if the soil is heavy clay or has tight formation1 yet shows some porosity from percolation tests1 the efficiency of the field may be increased by placing below the tile lines #ab to #ae inches of additional filter material 7washed gravel1 crushed stone1 slag1 clean cinders1 or clean bank-run gravel #c_/d to #b-a_/b inches in size74 ,when the surface soil is tight and is underlain by porous soil1 sufficient drainage is sometimes obtained for the smaller installations by omitting the tile field and providing a dry well at the end of the effluent sewer1 provided the water table will not be contaminated4 ,larger systems under such soil conditions should have a tile field1 and absorption can be increased by boring #f- or #h-;inch holes down to the porous stratum and filling them with gravel or sand2 the holes should be #d to #f feet apart4 ,another and perhaps the best practice is to excavate the tile trenches #d to #f feet and install a lower tile line1 as shown in figure #aj4 ,this latter method is especially desirable if the upper tight stratum is especially thick1 or if there is no porous lower stratum1 or if in irrigated regions and where the disposal field is limited in area4 ,where the underdrain tile is not used1 the absorption capacity of the field can be increased by providing a rock-filled trench across the lower end of the tiles for the full width of the field4 ,the depth should be not less than #e feet and the width not less than #c feet4 ,on account of the beneficial action of bacteria in the upper soil layers it is highly desirable to confine the effluent near the surface rather than to use underdrains4 ,purification becomes slower and less effective1 the deeper the drains4 ,in situations where the soil contains considerable moisture or is even saturated1 the field may be improved by partially encircling it with a tile line laid to serve as a drain4 ,such a line should be on the high side and have surface outlets for removing the water from the soil4 ,it should not be laid so close to a disposal tile line that it will drain the sewage effluent from the disposal field onto the surface of the ground4 ,illustration3 ,slope of disposal tile #b to #d inches per #ajj feet4 ,slope of underdrain tile not less than above4 ,plug upper end of underdrain tile lines1 lower end to discharge into rock-filled seepage pit or into other approved outlet4 ,figure #aj4--;,filter trench with underdrains4 ,when the tile field is underlain by stratified rock or where under-drainage is necessary1 advice should be sought from the public health authorities1 as regulations in some ,states may not permit the use of certain methods4 ,,care ,,and ,,maintenance ,,of ,,septic ,,tanks ,a septic tank when first used does not need starters1 such as yeast1 to promote bacterial action4 ,a good septic tank normally requires no maintenance other than a yearly inspection and an occasional cleaning4 ,frequency of cleaning depends on the capacity of the tank and the quantity and composition of the sewage4 ,tanks of the size recommended in this bulletin may require cleaning at intervals of #c to #e years4 ,the tank should be cleaned when #ah to #bj inches of sludge and scum has accumulated4 ,if a drain has not been provided1 sludge may be removed by bailing or by pumping with a sludge or bilge pump4 ,it is not necessary to remove the entire liquid contents4 ,burial in a shallow pit or trench with at least #ah to #bd inches of earth cover at a point remote from water sources is the most practical method for disposing of these wastes4 ,a septic tank is intended to handle sewage only4 ,coffee grounds and ground garbage may be included if there is an ample supply of water for flushing and the tank is cleaned more frequently than would otherwise be done4 ,the size of the tank should be increased at least #be percent if these materials are included in the sewage4 ,do not use matches or an open flame to inspect a septic tank1 as the gasses produced by decomposing sewage may explode and cause serious injury4 ,,effect ,,of ,,drain ,,solvents ,,and ,,other ,,materials ,soap1 drain solvents1 and other mild cleaning or disinfecting solutions used for normal household purposes cause no trouble in the tank4 ,constant use in large quantities1 however1 and disinfected wastes from the sickroom may prove harmful4 ,wastes from milk rooms1 strong chemicals used in sterilizing equipment or in photographic work1 and the wastes from filters or water softeners not only reduce bacterial action but also cause abnormally rapid accumulations of sludge and clogging of the tile lines4 ,,protection ,,against ,,freezing ,septic-tank systems seldom freeze when in constant use4 ,warm water and the decomposition of the sewage usually maintain above-freezing temperatures4 ,in cold regions there is trouble from freezing if various parts of the system are not covered adequately4 ,if the system is to be out of service for a period of time or if exposure is severe1 it may be advisable to mound over the poorly protected parts of the system with earth1 hay1 straw1 brush1 leaves1 manure1 snow1 or the like4 ,in cold regions it is not advisable to install the entire system below frost depth1 as this will remove the effluent from the action of the aerobic bacteria in the upper layers of the soil and make the system generally less accessible4 ,new systems put into operation during very cold weather may freeze unless large quantities of hot water are discharged during the first few weeks4 ,,septic-,,tank ,,troubles ,in sewage disposal1 clogging of the disposal field is the most common trouble4 ,this may be caused 7#a7 by a tank too small for the volume of sewage1 7#b7 by failure to clean the tank regularly1 7#c7 by interior arrangement that does not provide slow flow through the tank or that allows scum or sludge to pass out with the effluent1 or 7#d7 by a disposal field that is too small or is incorrectly built4 ,the remedy for a clogged disposal field is to dig up and clean the tiles and re-lay them #c or #d feet to one side or the other of their former position4 ,sometimes a tile line can be cleaned by opening up the line at each end and flushing it thoroughly with a hose4 ,with this method provision must be made to drain off and safely dispose of the water used for flushing4 ,tile lines laid with improper slope allow the effluent to collect in a limited area and saturate the soil1 causing odors4 ,bacteria cannot work in such areas1 where the soil becomes sour1 or sewage-sick4 ,these lines must be relaid on the correct slope4 ,odors or a water-logged soil may also indicate that the disposal field is too small4 ,house sewers frequently clog4 ,this is due1 in most cases1 to roots and less frequently to trash1 garbage1 or other foreign materials discharged with the sewage4 ,greases in the sewer may cause trouble1 especially when the slope is insufficient to give the sewage a cleansing velocity4 ,drain solvents will sometimes remove the obstruction1 but more often it is necessary to clean the sewer by rodding4 ,in some cases it may be necessary to dig up the line to reach the obstruction or1 at least1 to open the line so that it can be rodded from two directions4 ,when it has been cleaned1 a manhole could be built for use in case of future trouble4 ,if stoppage is due to roots it may be necessary to re-lay the sewer with root-tight joints1 or to move either the sewer or the vegetation so that roots cannot reach the line4 ,,grease ,,traps ,grease traps 7fig4 #aa7 are not recommended for the average farm1 because they clog easily and require frequent cleaning1 but they are desirable for boarding houses and tourist camps where large quantities of grease are produced4 ,the septic tank if of proper design and size will take care of the normal grease from most farm kitchens4 ,the traps must be several times larger than the quantity of greasy water discharged into them at any one time1 in order to allow the greases to rise1 but they should not be of less than #cj gallons' capacity4 ,the trap is best located in an accessible place in the basement or under the house close to the source of grease and safe from frost4 ,outdoor locations at shallow depths require a covering for insulation against freezing4 ,grease traps should be connected to the kitchen sink only and not to laundry1 shower1 or water-closet wastes4 ,they must be cleaned periodically for satisfactory operation1 and the outlet should be properly trapped4 ,illustration3 ,figure #aa4--,typical grease trap4 ,,disposal ,,of ,,drainage ,,from ,,fixtures ,,other ,,than ,,toilets ,when the farmhouse does not have an indoor toilet but does have a kitchen sink or other similar fixtures1 the drainage can be disposed of as shown in figure #ab4 ,even where septic tanks have been installed1 it is sometimes advisable to have a second disposal field for other fixtures than the toilet1 to avoid overloading the tank1 especially where large quantities of laundry water are discharged at one time4 ,illustration3 ,figure #ab4--;,disposal of drainage from kitchen fixtures1 using a line of terra cotta or fiber drain tile surrounded with gravel4 ,one or two rock-filled pits at the end of the line increase the absorption area and are desirable where there are several fixtures or the soil is nonporous4 ,the pits may be lined with boards or masonry laid without mortar and provided with a tight cover4 ,these wastes are not likely to create serious health hazards1 but they become nuisances if discharged promiscuously on the ground surface4 ,such drainage should never be permitted on the watershed of a spring4 ,coarse sand and gravel1 #ab to #ah inches deep1 may be placed on the bottom of the pit1 to strain out small particles of solids1 which might clog the pores of the soil4 ,if1 after a few years1 the sand or gravel becomes clogged with solids1 it should be replaced with clean materials4 ,if excessive quantities of grease are permitted to enter the sink drain1 a grease trap may be advisable4 ,,cesspools ,cesspools are cheap in first cost but high in maintenance costs and often become nuisances4 ,they should be located at least #aej feet from wells1 #ae feet from seepage pits and property lines1 and #bj feet from dwelling foundations4 ,they should never be used in the vicinity of shallow wells and1 in any case1 only where permitted by ,state regulations4 ,the cesspool depends for its action upon seepage into the surrounding soil and consequently is particularly unsatisfactory in tight clay soils4 ,in more open sand and gravel soils the seepage is reduced as the pores of the soil become clogged with particles of solids1 until it stops entirely1 and overflowing occurs4 ,emptying and then cleaning the walls and floor of a cesspool do not fully open up the clogged soil pores1 and overflowing can be expected to occur soon again4 ,solids in cesspools must be removed from time to time by bailing or pumping and should then be buried #ah to #bd inches deep in a trench where the water supply will not be endangered4 ,caustic potash 7lye7 will to some extent liquefy solids in a cesspool4 ,this treatment does not eliminate the necessity of removing the contents when periodic inspection shows that the cesspool is nearly full4 ,caustic potash converts the greases into soft soap1 whereas caustic soda forms a hard soap that does not readily dissolve4 ,the chemical treatment is not effective in liquefying solids in the pores of the soil surrounding the cesspool4 ,illustration3 ,figure #ac4--;,a neat1 whitewashed lattice along the paved walkway provides protection from cold wind and rain and gives added privacy4 ,when clogging continues and cannot be corrected1 in most cases the best solution to the problem would be to abandon the cesspool and install a septic-tank system with tile disposal field4 ,the cesspool should be completely filled with stones1 earth1 or other solid materials to avoid possible cave-ins4#h #h ,see ,the ,septic ,tank1 p4 #h4 ,,privies ,a privy when safely located and properly built and maintained is satisfactory for its purpose on the farm4 ,privies should be built #ej to #aej feet from the farmhouse1 preferably on the opposite side of the house from prevailing winds1 and at least #ej feet from the well4 ,a site downhill from the well is generally safest4 ,in some cases1 however1 the ground water may flow in a direction opposite to the slope of the surface1 in which case the privy should be built on the other side of the well4 ,direction of flow may sometimes be learned from soil surveys1 well-driller's data1 or other similar sources4 ,a distance of at least #f feet from fences or other buildings allows for proper mounding of the privy and keeps it away from roof drainage from adjacent buildings4 ,good1 tight construction with screened ventilators keeps insects and birds from entering1 prevents rapid deterioration of the building1 and provides greater comfort for the user4 ,certain features1 while not essential to sanitation and satisfactory service1 add to personal convenience4 ,a paved walkway1 well protected from cold winds and rain1 is desirable4 ,a neat1 whitewashed lattice1 as shown in figure #ac1 an arbor covered with vines1 or a hedge screen adds to privacy4 ,the earth-pit privy is the simplest to build and the one most widely used4 ,it is not generally recommended in localities where underground rock has crevices4 ,for a sanitary type of privy with reinforced concrete#i floor1 riser1 and supporting sills see figure #ad4 ,because privy units are commonly used as urinals1 the use of impervious materials for risers and floors facilitates cleanliness4 ,in the colder climates1 wood treated with a preservative is durable and reduces the problem of moisture condensation4 ,therefore1 wood could be used if approved by the ,state department of health4 #i ,for information on making concrete see ,farmers' ,bulletin #aggb1 ,use of ,concrete on the ,farm4 ,when it is considered impracticable to build the slab and riser of concrete1 these parts may be of wood1 as shown in figure #af4 ,the building itself may be as shown in either illustration4 ,a wood structure is easy to move to a new location4 ,a pit with a minimum capacity of #ej cubic feet#aj will usually serve five people over a period of #e to #aj years4 ,the privy should be moved when the pit is filled to within #ah or #bj inches of the top and a strong disinfectant spread in the old pit before covering it with earth4 #aj ,recommended by the ,committee on ,promotion of ,rural ,sanitation1 ,public ,health ,engineering ,section of the ,american ,public ,health ,association1 #aicb4 ,illustration3 ,figure #ad4--,sanitary type of privy4 ,detailed plans and a bill of materials for this design can be had from the ,united ,states ,public ,health ,service1 ,washington #be1 ,d4 ,c4 ,it is important to have the earth-pit privy more than #ej feet from the well even where the water table is not near the surface4 ,the ground water should flow from the well toward the privy1 and it is important that this direction of flow be determined in advance4 ,wood is most commonly employed for the main part of the building4 ,the ground outside should be sloped as shown1 to shed water away from the building1 and the roof should extend beyond the walls to shed water away from the pit4 ,,care ,,and ,,maintenance ,all privies require periodic attention4 ,seats and covers should be washed weekly with soap and water or with disinfectants1 such as cresol1 pine oil1 and hypochlorite or chloride of lime4 ,these have deodorant properties and are available at most grocery or drug stores4 ,druggists generally carry a more refined product and consequently the price is higher4 ,during the fly season fly and mosquito eggs will be destroyed by pouring half a pint of crude oil1 crankcase oil1 fuel oil1 kerosene1 or borax solution 7#a pound powdered borax dissolved in about #aj gallons of water7 over the contents of the pit about once a week4 ,illustration3 ,figure #ae4--,pit privy of all-wood construction4 ,the sills and riser of this type should either be treated or made of cypress1 redwood1 cedar1 locust1 fir1 or other decay-resistant wood4 ,odors from privy pits and vaults can be reduced by covering the contents with dry earth1 ashes1 manure1 or sawdust4 ,these materials fill up the pit rather quickly1 but can be used where other deodorants are not available4 ,sometimes two cakes of yeast dissolved in #b gallons of water are effective in reducing odors4 ,commercial deodorants are available from suppliers of disinfectants4 ,if a person in the family has typhoid fever or is a carrier of that disease or has dysentery1 it is advisable to disinfect the excreta4 ,fire1 live steam1 boiling water1 and such chemicals as caustic soda 7sodium hydroxide71 caustic potash 7potassium hydroxide71 or hypochlorite or chloride of lime may be used4 ,the heat generated by the slacking of quicklime is also effective4 ,best results are obtained if the infected material is treated prior to depositing it in the privy4 ,further advice may be obtained from physicians1 local health officers1 or ,state health departments4 ,,chemical ,,closets ,in general1 chemical closets should be used only where there are elderly or infirm people unable to get outdoors1 particularly in winter-time4 ,in some localities their use is forbidden by law because of improper maintenance4 ,strict adherence to the manufacturer's directions for making the installation is necessary to obtain satisfactory service4 ,the chief advantage of chemical closets is that they may be within or adjoining the house and used without regard to soil or ground-water conditions4 ,the caustic chemicals required1 if used properly1 reduce the quantity of solid matter by liquefying action1 disinfect and deodorize the contents1 and lessen danger from flies4 ,disadvantages are the cost of the chemicals and necessity for careful and constant maintenance4 ,the chemical-tank closet is generally recommended rather than the dry-type chemical closet4 ,three variations of tanks are available commercially4 ,one type contains a clean-out opening in the top of the tank1 through which the contents are removed by pumping or bailing4 ,the second type has1 in addition to a clean-out opening1 a drain valve at the bottom1 which is operated by a handle extending to a clean-out opening1 so that gravity drainage of the tank is possible4 ,the third type is self-draining2 as the excreta are added an equal volume of liquid is spilled out the overflow4 ,the solid matter must be removed manually or through the sludge drain4 ,the last-mentioned type requires frequent addition of chemicals1 and the others are recharged after each emptying4 ,the presence of odor is an indication of insufficient chemical or of the need for emptying and recharging4 ,the same precautions apply to selecting an area for disposing of the tank wastes as to disposing of the materials removed from cesspools4#aa ,since the contents of chemical closets are caustic1 they may kill vegetation with which they come in contact4 #aa ,for disposal methods in tight soils1 see p4 #af4 ,the dry-type chemical closet is cheap1 simple1 and easy to install but requires frequent emptying4 ,pine tar and coal tar will accomplish only partial disinfection and deodorization1 but caustic disinfectants produce liquefication in addition if used in sufficient quantities4 ,the caustic chemicals may cause burns if the receptacle is too full or if spilled where they come in contact with the body4 ,this form of closet is more of an expedient than a permanent installation1 and daily care is necessary to prevent the development of insanitary conditions4 ,,disposal ,,of ,,garbage ,,and ,,trash ,domestic garbage and trash on farms can be divided into four classes--7#a7 waste of plant or animal origin suitable for animal feed1 7#b7 unpalatable plant or animal waste1 7#c7 combustible trash1 and 7#d7 noncombustible material4 ,the disposal of these wastes is simplified if the four classes are kept separate4 ,trash to be burned should be kept dry4 ,coffee grounds1 tea leaves1 citrus rinds1 fish heads1 entrails1 eggshells1 and similar material are most readily handled if drained and put in paper sacks4 ,cans should be placed where they will not collect water and become breeding places for mosquitoes4 ,cans will corrode faster if heated sufficiently to burn off all grease4 ,when the trash accumulates it should be hauled to some out-of-the-way place1 such as a gully1 or buried4 ,neat-appearing garbage containers are desirable for kitchen use and should be small enough to require daily emptying4 ,large containers may be placed within easy reach outside the house and screened with a lattice fence or shrubbery4 ,substantial containers of rust-resistant metal will not quickly become an eyesore and a nuisance4 ,tight covers should be used to keep out prowling animals and to eliminate the habit of tossing wastes from the back door4 ,open or wooden containers are not recommended4 ,a good way to protect the garbage pail is to place it in a small pit that has a manhole frame and a lid that can be raised by foot pedal4 ,a gravel bottom in the pit will assist in draining water away4 ,outdoor receptacles1 if emptied and cleaned once a week1 generally do not become foul4 ,grease1 coffee grounds1 and other similar materials that adhere to the sides of containers can be removed by scraping with a little sand prior to scalding4 ,electrically operated units grind garbage and bones and discharge the material through the kitchen-sink drain4 ,they will not handle tin cans1 glass1 and the like4 ,they may be used on farms if the septic tank is larger than normal and if sufficient water is available for flushing the drain to prevent clogging4 ,garbage to be fed to animals should be preserved as carefully as is human food4 ,to prevent the spread of trichinosis and other diseases1 it should be cooked before it is fed to hogs4 ,garbage left uneaten by the animals should be disposed of by one of the methods described above4 ,incineration is the most sanitary method of disposing of farm wastes4 ,garbage1 however1 is not easily burned4 ,figure #af shows a type of incinerator#ab suitable for farm homes4 ,details of construction for a brick incinerator are given in figure #ag4 ,brick1 stone1 concrete1 or other fire-resistant material may be used4 ,commercial incinerators1 some of which are designed to be built into the house1 also are available1 although these cost considerably more than the home-made type shown4 #ab ,blueprints of this design may be obtained from the extension agricultural engineers at most of the ,state colleges4 ,a limited quantity of refuse may be burned in a kitchen range or a furnace1 but it may cause accumulations of grease in the flue and require frequent cleaning to prevent fire4 ,next to burning1 burial is the most desirable method of waste disposal4 ,waste material may be deposited in a trench #c or #d feet wide1 #g or #h feet long1 and #d or #e feet deep and covered with earth when filled to within #ah inches of the top4 ,if there is no fire hazard1 the contents of the trench may be burned4 ,garbage may be included in a compost heap with leaves1 peat1 manure1 and similar materials4 ,the compost pile should be in an inconspicuous place1 built up to the desired height with materials that will rot1 and then covered with #b or #c inches of earth4 ,the top should be level and the sides steep sloping4 ,it is necessary that the material being composted be kept moist2 otherwise it will not rot4 ,frequently commercial fertilizer is added to increase the fertilizing value of the compost4 ,ashes and clinkers removed from furnaces should be placed in metal containers to eliminate fire hazard4 ,wood ashes may be spread on the lawn or garden1 as they have some fertilizing value4 ,illustration3 ,figure #af4--;,a satisfactory incinerator for household use4 ,illustration3 ,figure #ag4--;,details of construction of the household incinerator pictured in figure #af4 ,trash burners of various designs suitable for burning small quantities of paper and rags are available or may be improvised4 ,the main requirements are provision for adequate draft and for preventing the escape of burning paper or live embers4 ,u4 ,s4 ,,government ,,printing ,,office3 #aidh ,for sale by the ,superintendent of ,documents1 ,u4 ,s4 ,government ,printing ,office ,washington #be4 ,d4 ,c4 -- ,price #aj cents 99 99 99 99 99 ,transcriber ,note ,illustrations were repositioned so as to not split paragraphs4