Slope of disposal tile 2 to 4 inches per 100 feet.Slope of underdrain tile not less than above.Plug upper end of underdrain tile lines, lower endto discharge into rock-filled seepage pit or intoother approved outlet.Figure 10.—Filter trench with underdrains.
Slope of disposal tile 2 to 4 inches per 100 feet.Slope of underdrain tile not less than above.Plug upper end of underdrain tile lines, lower endto discharge into rock-filled seepage pit or intoother approved outlet.
Figure 10.—Filter trench with underdrains.
When the tile field is underlain by stratified rock or where under-drainage is necessary, advice should be sought from the public health authorities, as regulations in some States may not permit the use of certain methods.
CARE AND MAINTENANCE OF SEPTIC TANKS
A septic tank when first used does not need starters, such as yeast, to promote bacterial action. A good septic tank normally requires no maintenance other than a yearly inspection and an occasional cleaning. Frequency of cleaning depends on the capacity of the tank and the quantity and composition of the sewage. Tanks of the size recommended in this bulletin may require cleaning at intervals of 3 to 5 years.
The tank should be cleaned when 18 to 20 inches of sludge and scum has accumulated. If a drain has not been provided, sludge may be removed by bailing or by pumping with a sludge or bilge pump. It is not necessary to remove the entire liquid contents. Burial in a shallow pit or trench with at least 18 to 24 inches of earth cover at a point remote from water sources is the most practical method for disposing of these wastes.
A septic tank is intended to handle sewage only. 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 done. The size of the tank should be increased at least 25 percent if these materials are included in the sewage.
Do not use matches or an open flame to inspect a septic tank, as the gasses produced by decomposing sewage may explode and cause serious injury.
Do not use matches or an open flame to inspect a septic tank, as the gasses produced by decomposing sewage may explode and cause serious injury.
EFFECT OF DRAIN SOLVENTS AND OTHER MATERIALS
Soap, drain solvents, and other mild cleaning or disinfecting solutions used for normal household purposes cause no trouble in the tank. Constant use in large quantities, however, and disinfected wastes from the sickroom may prove harmful.
Wastes from milk rooms, strong chemicals used in sterilizing equipment or in photographic work, 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 lines.
PROTECTION AGAINST FREEZING
Septic-tank systems seldom freeze when in constant use. Warm water and the decomposition of the sewage usually maintain above-freezing temperatures. In cold regions there is trouble from freezing if various parts of the system are not covered adequately. If the system is to be out of service for a period of time or if exposure is severe, it may be advisable to mound over the poorly protected parts of the system with earth, hay, straw, brush, leaves, manure, snow, or the like.
In cold regions it is not advisable to install the entire system below frost depth, 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 accessible.
New systems put into operation during very cold weather may freeze unless large quantities of hot water are discharged during the first few weeks.
SEPTIC-TANK TROUBLES
In sewage disposal, clogging of the disposal field is the most common trouble. This may be caused (1) by a tank too small for the volume of sewage, (2) by failure to clean the tank regularly, (3) by interior arrangement that does not provide slow flow through the tank or that allows scum or sludge to pass out with the effluent, or (4) by a disposal field that is too small or is incorrectly built.
The remedy for a clogged disposal field is to dig up and clean the tiles and re-lay them 3 or 4 feet to one side or the other of their former position. Sometimes a tile line can be cleaned by opening up the line at each end and flushing it thoroughly with a hose. With this method provision must be made to drain off and safely dispose of the water used for flushing.
Tile lines laid with improper slope allow the effluent to collect in a limited area and saturate the soil, causing odors. Bacteria cannot work in such areas, where the soil becomes sour, or "sewage-sick." These lines must be relaid on the correct slope. Odors or a water-logged soil may also indicate that the disposal field is too small.
House sewers frequently clog. This is due, in most cases, to roots and less frequently to trash, garbage, or other foreign materials discharged with the sewage. Greases in the sewer may cause trouble, especially when the slope is insufficient to give the sewage a cleansing velocity. Drain solvents will sometimes remove the obstruction, but more often it is necessary to clean the sewer by rodding. In some cases it may be necessary to dig up the line to reach the obstruction or, at least, to open the line so that it can be rodded from two directions. When it has been cleaned, a manhole could be built for use in case of future trouble. If stoppage is due to roots it may be necessary to re-lay the sewer with root-tight joints, or to move either the sewer or the vegetation so that roots cannot reach the line.
Figure 11.—Typical grease trap.
Figure 11.—Typical grease trap.
Grease traps (fig. 11) are not recommended for the average farm, because they clog easily and require frequent cleaning, but they are desirable for boarding houses and tourist camps where large quantities of grease are produced. The septic tank if of proper design and size will take care of the normal grease from most farm kitchens.
The traps must be several times larger than the quantity of greasy water discharged into them at any one time, in order to allow the greases to rise, but they should not be of less than 30 gallons' capacity.
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 frost. Outdoor locations at shallow depths require a covering for insulation against freezing. Grease traps should be connected to the kitchensink only and not to laundry, shower, or water-closet wastes. They must be cleaned periodically for satisfactory operation, and the outlet should be properly trapped.
When the farmhouse does not have an indoor toilet but does have a kitchen sink or other similar fixtures, the drainage can be disposed of as shown infigure 12. Even where septic tanks have been installed, it is sometimes advisable to have a second disposal field for other fixtures than the toilet, to avoid overloading the tank, especially where large quantities of laundry water are discharged at one time.
Figure 12.—Disposal of drainage from kitchen fixtures, using a line of terra cotta or fiber drain tile surrounded with gravel. 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 nonporous. The pits may be lined with boards or masonry laid without mortar and provided with a tight cover.
Figure 12.—Disposal of drainage from kitchen fixtures, using a line of terra cotta or fiber drain tile surrounded with gravel. 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 nonporous. The pits may be lined with boards or masonry laid without mortar and provided with a tight cover.
These wastes are not likely to create serious health hazards, but they become nuisances if discharged promiscuously on the ground surface. Such drainage should never be permitted on the watershed of a spring.
Coarse sand and gravel, 12 to 18 inches deep, may be placed on the bottom of the pit, to strain out small particles of solids, which might clog the pores of the soil. If, after a few years, the sand or gravel becomes clogged with solids, it should be replaced with clean materials.
If excessive quantities of grease are permitted to enter the sink drain, a grease trap may be advisable.
Cesspools are cheap in first cost but high in maintenance costs and often become nuisances. They should be located at least 150 feet from wells, 15 feet from seepage pits and property lines, and 20 feet from dwelling foundations. They should never be used in the vicinity of shallow wells and, in any case, only where permitted by State regulations.
The cesspool depends for its action upon seepage into the surrounding soil and consequently is particularly unsatisfactory in tight clay soils. In more open sand and gravel soils the seepage is reduced as the pores of the soil become clogged with particles of solids, until it stops entirely, and overflowing occurs. Emptying and then cleaning the walls and floor of a cesspool do not fully open up the clogged soil pores, and overflowing can be expected to occur soon again.
Solids in cesspools must be removed from time to time by bailing or pumping and should then be buried 18 to 24 inches deep in a trench where the water supply will not be endangered. Caustic potash (lye) will to some extent liquefy solids in a cesspool. This treatment does not eliminate the necessity of removing the contents when periodic inspection shows that the cesspool is nearly full. Caustic potash converts the greases into soft soap, whereas caustic soda forms a hard soap that does not readily dissolve. The chemical treatment is not effective in liquefying solids in the pores of the soil surrounding the cesspool.
Figure 13.—A neat, whitewashed lattice along the paved walkway provides protection from cold wind and rain and gives added privacy.
Figure 13.—A neat, whitewashed lattice along the paved walkway provides protection from cold wind and rain and gives added privacy.
When clogging continues and cannot be corrected, in most cases the best solution to the problem would be to abandon the cesspool and install a septic-tank system with tile disposal field. The cesspool should be completely filled with stones, earth, or other solid materials to avoid possible cave-ins.[8]
[8]SeeThe Septic Tank,p. 8.
[8]SeeThe Septic Tank,p. 8.
A privy when safely located and properly built and maintained is satisfactory for its purpose on the farm. Privies should be built 50 to 150 feet from the farmhouse, preferably on the opposite side of the house from prevailing winds, and at least 50 feet from the well. A site downhill from the well is generally safest. In some cases, however, the ground water may flow in a direction opposite to the slope of the surface, in which case the privy should be built on the other side of the well. Direction of flow may sometimes be learned from soil surveys, well-driller's data, or other similar sources. A distance of at least 6 feet from fences or other buildings allows for proper mounding of the privy and keeps it away from roof drainage from adjacent buildings.
Good, tight construction with screened ventilators keeps insects and birds from entering, prevents rapid deterioration of the building, and provides greater comfort for the user.
Certain features, while not essential to sanitation and satisfactory service, add to personal convenience. A paved walkway, well protected from cold winds and rain, is desirable. A neat, whitewashed lattice, as shown infigure 13, an arbor covered with vines, or a hedge screen adds to privacy.
The earth-pit privy is the simplest to build and the one most widely used. It is not generally recommended in localities where underground rock has crevices.
For a sanitary type of privy with reinforced concrete[9]floor, riser, and supporting sills seefigure 14. Because privy units are commonly used as urinals, the use of impervious materials for risers and floors facilitates cleanliness. In the colder climates, wood treated with a preservative is durable and reduces the problem of moisture condensation. Therefore, wood could be used if approved by the State department of health.
[9]For information on making concrete see Farmers' Bulletin 1772, Use of Concrete on the Farm.
[9]For information on making concrete see Farmers' Bulletin 1772, Use of Concrete on the Farm.
When it is considered impracticable to build the slab and riser of concrete, these parts may be of wood, as shown infigure 16. The building itself may be as shown in either illustration. A wood structure is easy to move to a new location.
A pit with a minimum capacity of 50 cubic feet[10]will usually serve five people over a period of 5 to 10 years. The privy should be moved when the pit is filled to within 18 or 20 inches of the top and a strong disinfectant spread in the old pit before covering it with earth.
[10]Recommended by the Committee on Promotion of Rural Sanitation, Public Health Engineering Section of the American Public Health Association, 1932.
[10]Recommended by the Committee on Promotion of Rural Sanitation, Public Health Engineering Section of the American Public Health Association, 1932.
Figure 14.—Sanitary type of privy. Detailed plans and a bill of materials for this design can be had from the United States Public Health Service, Washington 25, D. C.
Figure 14.—Sanitary type of privy. Detailed plans and a bill of materials for this design can be had from the United States Public Health Service, Washington 25, D. C.
It is important to have the earth-pit privy more than 50 feet from the well even where the water table is not near the surface. The ground water should flow from the well toward the privy, and it is important that this direction of flow be determined in advance.
Wood is most commonly employed for the main part of the building. The ground outside should be sloped as shown, to shed water away from the building, and the roof should extend beyond the walls to shed water away from the pit.
CARE AND MAINTENANCE
All privies require periodic attention. Seats and covers should be washed weekly with soap and water or with disinfectants, such as cresol, pine oil, and hypochlorite or chloride of lime. These have deodorant properties and are available at most grocery or drug stores. Druggists generally carry a more refined product and consequently the price is higher.
During the fly season fly and mosquito eggs will be destroyed by pouring half a pint of crude oil, crankcase oil, fuel oil, kerosene, or borax solution (1 pound powdered borax dissolved in about 10 gallons of water) over the contents of the pit about once a week.
Figure 15.—Pit privy of all-wood construction. The sills and riser of this type should either be treated or made of cypress, redwood, cedar, locust, fir, or other decay-resistant wood.
Odors from privy pits and vaults can be reduced by covering the contents with dry earth, ashes, manure, or sawdust. These materials fill up the pit rather quickly, but can be used where other deodorants are not available. Sometimes two cakes of yeast dissolved in 2 gallons of water are effective in reducing odors. Commercial deodorants are available from suppliers of disinfectants.
If a person in the family has typhoid fever or is a carrier of that disease or has dysentery, it is advisable to disinfect the excreta. Fire, live steam, boiling water, and such chemicals as caustic soda (sodium hydroxide), caustic potash (potassium hydroxide), or hypochlorite or chloride of lime may be used. The heat generated by the slacking of quicklime is also effective. Best results are obtained if the infected material is treated prior to depositing it in the privy. Further advice may be obtained from physicians, local health officers, or State health departments.
In general, chemical closets should be used only where there are elderly or infirm people unable to get outdoors, particularly in winter-time. In some localities their use is forbidden by law because of improper maintenance. Strict adherence to the manufacturer's directions for making the installation is necessary to obtain satisfactory service. 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 conditions. The caustic chemicals required, if used properly, reduce the quantity of solid matter by liquefying action, disinfect and deodorize the contents, and lessen danger from flies. Disadvantages are the cost of the chemicals and necessity for careful and constant maintenance.
The chemical-tank closet is generally recommended rather than the dry-type chemical closet. Three variations of tanks are available commercially. One type contains a clean-out opening in the top of the tank, through which the contents are removed by pumping or bailing. The second type has, in addition to a clean-out opening, a drain valve at the bottom, which is operated by a handle extending to a clean-out opening, so that gravity drainage of the tank is possible. The third type is self-draining; as the excreta are added an equal volume of liquid is spilled out the overflow. The solid matter must be removed manually or through the sludge drain.
The last-mentioned type requires frequent addition of chemicals, and the others are recharged after each emptying. The presence of odor is an indication of insufficient chemical or of the need for emptying and recharging. The same precautions apply to selecting an area for disposing of the tank wastes as to disposing of the materials removed from cesspools.[11]Since the contents of chemical closets are caustic, they may kill vegetation with which they come in contact.
[11]For disposal methods in tight soils, seep. 16.
[11]For disposal methods in tight soils, seep. 16.
The dry-type chemical closet is cheap, simple, and easy to install but requires frequent emptying. Pine tar and coal tar will accomplish only partial disinfection and deodorization, but caustic disinfectants produce liquefication in addition if used in sufficient quantities. Thecaustic chemicals may cause burns if the receptacle is too full or if spilled where they come in contact with the body.
This form of closet is more of an expedient than a permanent installation, and daily care is necessary to prevent the development of insanitary conditions.
Domestic garbage and trash on farms can be divided into four classes—(1) waste of plant or animal origin suitable for animal feed, (2) unpalatable plant or animal waste, (3) combustible trash, and (4) noncombustible material. The disposal of these wastes is simplified if the four classes are kept separate.
Trash to be burned should be kept dry. Coffee grounds, tea leaves, citrus rinds, fish heads, entrails, eggshells, and similar material are most readily handled if drained and put in paper sacks.
Cans should be placed where they will not collect water and become breeding places for mosquitoes. Cans will corrode faster if heated sufficiently to burn off all grease. When the trash accumulates it should be hauled to some out-of-the-way place, such as a gully, or buried.
Neat-appearing garbage containers are desirable for kitchen use and should be small enough to require daily emptying. Large containers may be placed within easy reach outside the house and screened with a lattice fence or shrubbery. Substantial containers of rust-resistant metal will not quickly become an eyesore and a nuisance. Tight covers should be used to keep out prowling animals and to eliminate the habit of tossing wastes from the back door. Open or wooden containers are not recommended.
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 pedal. A gravel bottom in the pit will assist in draining water away.
Outdoor receptacles, if emptied and cleaned once a week, generally do not become foul. Grease, coffee grounds, and other similar materials that adhere to the sides of containers can be removed by scraping with a little sand prior to scalding.
Electrically operated units grind garbage and bones and discharge the material through the kitchen-sink drain. They will not handle tin cans, glass, and the like. 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 clogging.
Garbage to be fed to animals should be preserved as carefully as is human food. To prevent the spread of trichinosis and other diseases, it should be cooked before it is fed to hogs. Garbage left uneaten by the animals should be disposed of by one of the methods described above.
Incineration is the most sanitary method of disposing of farm wastes. Garbage, however, is not easily burned.Figure 16shows a type of incinerator[12]suitable for farm homes. Details of construction for a brick incinerator are given infigure 17. Brick, stone, concrete,or other fire-resistant material may be used. Commercial incinerators, some of which are designed to be built into the house, also are available, although these cost considerably more than the home-made type shown.
[12]Blueprints of this design may be obtained from the extension agricultural engineers at most of the State colleges.
[12]Blueprints of this design may be obtained from the extension agricultural engineers at most of the State colleges.
A limited quantity of refuse may be burned in a kitchen range or a furnace, but it may cause accumulations of grease in the flue and require frequent cleaning to prevent fire.
Next to burning, burial is the most desirable method of waste disposal. Waste material may be deposited in a trench 3 or 4 feet wide, 7 or 8 feet long, and 4 or 5 feet deep and covered with earth when filled to within 18 inches of the top. If there is no fire hazard, the contents of the trench may be burned.
Garbage may be included in a compost heap with leaves, peat, manure, and similar materials. The compost pile should be in an inconspicuous place, built up to the desired height with materials that will rot, and then covered with 2 or 3 inches of earth. The top should be level and the sides steep sloping. It is necessary that the material being composted be kept moist; otherwise it will not rot. Frequently commercial fertilizer is added to increase the fertilizing value of the compost.
Ashes and clinkers removed from furnaces should be placed in metal containers to eliminate fire hazard. Wood ashes may be spread on the lawn or garden, as they have some fertilizing value.
Figure 16.—A satisfactory incinerator for household use.
Figure 16.—A satisfactory incinerator for household use.
Figure 17.—Details of construction of the household incinerator pictured infigure 16.Click on image to view larger sized.
Figure 17.—Details of construction of the household incinerator pictured infigure 16.Click on image to view larger sized.
Trash burners of various designs suitable for burning small quantities of paper and rags are available or may be improvised. The main requirements are provision for adequate draft and for preventing the escape of burning paper or live embers.
U. S. GOVERNMENT PRINTING OFFICE: 1948
For sale by the Superintendent of Documents, U. S. Government Printing OfficeWashington 25. D. C. - Price 10 cents
Transcriber NoteIllustrations were repositioned so as to not split paragraphs.
Transcriber Note
Illustrations were repositioned so as to not split paragraphs.