Part 5

The 4-inch siphon has a drawing depth of 33 inches, and as the siphon chamber is 4 feet wide by 6 feet long the dose is about 500 gallons. The siphon cost $35. The 6-inch sewer to the switch box falls about 6 inches in 50 feet. The distribution field was thoroughly subsoiled, and about 800 feet of 3-inch tile was laid in each unit. At intervals of 25 feet along the distribution trenches 6-inch holes were dug through the clay stratum with a posthole digger. These holes were filled with stone and constitute the filter wells previously mentioned. All tile lines are surrounded with stone and coarse gravel, and the ground has been trimmed to give a uniform cover of 12 inches. All work was done by day labor in a thorough manner. As the men were doing other work at the same time the actual cost is not known, but it is believed the installation cost about $700.

=Cost data.=--Reliable cost figures are difficult to estimate. Labor, materials, freight, haulage, and other items vary greatly in different localities. The septic tank shown in Figure 21 contains about 1,000 bricks and is estimated to cost $60 complete. The septic tank shown in Figure 23 for 5 persons is estimated to cost $135; for 10 persons, $170; for 15 persons, $240; for 20 persons, $280. In Maryland, in 1916, the cost of installing a septic tank similar to that shown in Figure 23 (for 5 people), including 86 feet of 5-inch house sewer (55 feet of cast-iron pipe passing a well, and 31 feet of vitrified pipe) and 214 feet of second-quality 4-inch sewer pipe in the distribution area, was as follows:

Excavation, labor $7.50 Materials delivered 46.60 Three-inch siphon, including freight 15.75 Construction, labor 28.00 Supervision 5.00 ------ Total 102.85

The quotations in the following table will be found useful in making estimates of cost:

_Cost per foot of pipe and drain tile_

(Approximate retail prices, Washington, D. C., February, 1928)

+----------------------------------- | Size, in inches. Kind of pipe. +--------+--------+--------+-------- | 3 | 4 | 5 | 6 ------------------------------------+--------+--------+--------+-------- | | | | Extra heavy cast-iron soil pipe | $0.23 | $0.31 | $0.40 | $0.48 Vitrified salt-glazed sewer pipe | .15 | .15 | .22½ | .22½ Clay or shale drain tile | .06 | .07 | .10 | .13 | | | | ------------------------------------+--------+--------+--------+--------

The cost of cast-iron fittings may be roughly estimated as follows; Bends, one and one-half times the price of straight pipe; =T=-branches, two times the price of straight pipe; reducers, average of the prices of straight pipe at each end. The cost of clay bends, =T=-branches, reducers, and increasers may be roughly estimated at four times the price of straight pipe.

=Operation.=--Attention must be given to every plant to insure success. Unusual or excessive foulness should be investigated. No chemicals should be used in a septic tank; garbage, rags, newspaper, and other solids not readily soluble in water should be kept out of sewers and tanks. The plant should be inspected often, noting particularly if the siphon is operating satisfactorily. If scum forms in the settling chamber it should be removed, and the sludge should be bailed or pumped out yearly. Frequently tanks are not cleaned out for three or four years, resulting in large quantities of solid matter going through to the distribution system and clogging it. Clogging may occur in the tile or in the adjacent soil. In either case the tile should be dug up, cleaned, and relaid. In some cases it has been found advantageous to relay the tile between the former lines. When sewage is applied to fairly porous land at the slow rate here recommended and the plant is well handled the tile lines should operate satisfactorily for many years. Liming heavy soils tends to loosen and keep them sweet.

=Field data.=--As a basis for outlining or designing a suitable installation the following data should be known:

1. State, town, and whether in or near an incorporated municipality.

2. Usual number of persons to be served.

3. Average daily consumption of water in gallons.

4. Kind and depth of well, depth to water surface.

5. Character of soil, whether sandy, gravelly, loamy, clay, or muck.

6. Condition of soil as to drainage.

7. Character of subsoil.

8. Character of underlying rock and, if known, its depth below the surface.

9. Depth to ground water at both house and field where sewage is to be distributed.

10. Minimum winter temperature and approximate depth to which frost goes.

11. Number and kind of buildings to be connected with the sewer.

12. Number and kind of plumbing fixtures in each building.

13. Whether plumbing fixtures are to be put in the basement.

14. Depth of basement floor below ground.

A plan to scale or a sketch with dimensions showing property lines, buildings, wells, springs, and drainage outlets should be furnished. The direction of surface drainage should be indicated by arrows. The slope of the land (vertical fall in a stated horizontal distance) should be given or if possible a contour plan (showing lines of constant elevation) should be furnished.

GREASE TRAPS

Farm sewage may contain from 10 to 30 pounds of grease and fats per person per year. This grease, originating mainly in the kitchen-sink, hinders septic action and clogs pipes, filters, and soils. Half the grease may be stopped by a septic tank, but the remainder goes into the distribution system, interfering with its action. A grease trap is a device for separating the grease from other wastes. The need for it may be lessened by carefully depositing waste greases and fats with the garbage; but one should always be installed if the kitchen is carelessly managed or discharges quantities of greasy water as at institutions, hotels, boarding houses, and bakeshops.

A grease trap should have several times the capacity of the greatest quantity of greasy water discharged into it at one time, in order that the entering water shall be well cooled and the grease congealed. The solidified grease rises to the surface of the water in the trap and is retained therein. A dishpan of greasy water (2½ to 3 gallons) is the largest quantity likely to be discharged at one time from an ordinary kitchen-sink, hence the grease trap should have not less capacity than 7 or 8 gallons. Figure 33 shows three types of grease traps suitable for farm use. In each the outlet pipe has small clearance at the bottom. This feature, together with the =V=-shaped hopper bottom, tends to create a scouring velocity and thus prevent the accumulation of coffee grounds and other solid wastes in the bottom of the trap. A grease trap should be close to the sink it is intended to serve, but not within the kitchen, on account of objectionable odors when the trap is opened to remove grease. It is good practice to place the trap in the cellar or basement, where it is safe from frost yet close to the source of grease.

GENERAL PROCEDURE

Do not waste money by digging and partly constructing, afterwards seeking information. Prepare a plan and work from it. Get in touch with your county agricultural and home demonstration agents. Advice may be obtained also from extension workers, State agricultural colleges, State and local boards of health, the United States Public Health Service, and the United States Department of Agriculture. Do not guess distances and levels. Use a measuring tape and some type of level--engineer's, architect's, drainage, hand, or carpenter's. Study this bulletin, and design, lay out, and construct in accordance therewith. Remember to: (1) Isolate the septic tank--locate it 50 to 100 or more feet from any dwelling and, if practicable, to the leeward of prevailing summer breezes; (2) locate the cesspool or sewage-distribution field downhill from the well or spring, and, if possible, 300 feet therefrom; (3) select dry, porous, deeply drained ground for disposal of all sewage; (4) do not apply more sewage to a given area of land than can be thoroughly absorbed and oxidized; (5) lay sewers straight and below the reach of frost, ventilate them thoroughly, and make the joints water-tight and root-proof.

Makeshift methods, materials, or devices should be avoided or used sparingly. Do not place a vent pipe in the top of a cesspool or septic tank if near a dwelling. Siphon chamber and siphon may be omitted in those rare instances where it is feasible to discharge into salt water or into a large stream already badly polluted. Disposal of sewage in a running stream should be a last resort. Such practice endangers water supplies downstream, and unless the volume and velocity of flow are good nuisance may be created in the vicinity. Do not neglect inspection and operation. Clean out settling tanks yearly or oftener. All pipe lines below ground should be marked with iron or stone markers to facilitate examination, repair, or extension of the system.

There is a general but erroneous belief that the cost of sewerage is little in the city but almost prohibitive in the country. All personal and Realty properties in one eastern city represent a valuation of $10,382 per home, which pays $355 for sewers outside the cellar wall. An average farm in a Middle West State represents a valuation of $17,259. Is not the farmer justified in the small outlay required to dispose of the farm sewage? Because of the issuance of bonds and the apportionment of sewer assessments for a series of years the city dweller may have his burden distributed over a long period. The farmer does not pay interest on these obligations, and sewer work can be done more cheaply in the country than in the city.

Safe disposal of farm sewage is not a passing fad but a vital necessity. Besides being an asset a good sewerage installation greatly promotes the wholesomeness and healthfulness of the farm. Moreover the benefits are far-reaching, because farm products go into every home, and farm and urban populations mingle freely.

ORGANIZATION OF THE UNITED STATES DEPARTMENT OF AGRICULTURE

January 6, 1930

_Secretary of Agriculture_ Arthur M. Hyde.

_Assistant Secretary_ R. W. Dunlap.

_Director of Scientific Work_ A. F. Woods.

_Director of Regulatory Work_ Walter G. Campbell.

_Director of Extension Work_ C. W. Warburton.

_Director of Personnel and Business W. W. Stockberger. Administration._

_Director of Information_ M. S. Eisenhower.

_Solicitor_ E. L. Marshall.

_Weather Bureau_ Charles F. Marvin, _Chief_.

_Bureau of Animal Industry_ John R. Mohler, _Chief_.

_Bureau of Dairy Industry_ O. E. Reed, _Chief_.

_Bureau of Plant Industry_ William A. Taylor, _Chief_.

_Forest Service_ R. Y. Stuart, _Chief_.

_Bureau of Chemistry and Soils_ H. G. Knight, _Chief_.

_Bureau of Entomology_ C. L. Marlatt, _Chief_.

_Bureau of Biological Survey_ Paul G. Redington, _Chief_.

_Bureau of Public Roads_ Thomas H. MacDonald, _Chief_.

_Bureau of Agricultural Economics_ Nils A. Olsen, _Chief_.

_Bureau of Home Economics_ Louise Stanley, _Chief_.

_Plant Quarantine and Control Lee A. Strong, _Chief_. Administration_

_Grain Futures Administration_ J. W. T. Duvel, _Chief_.

_Food, Drug, and Insecticide Walter G. Campbell, _Director of Administration_ Regulatory Work, in Charge_.

_Office of Experiment Stations_ --------, _Chief_.

_Office of Cooperative Extension Work_ C. B. Smith, _Chief_.

_Library_ Claribel R. Barnett, _Librarian_.

U. S. GOVERNMENT PRINTING OFFICE: 1930

For sale by the Superintendent of Documents, ---- Price 10 cents Washington, D. C.

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Transcriber Note

Minor typos have been corrected. Illustrations were moved to prevent splitting paragraphs. Figure 19 was moved adjacent to the directions and specifications on Page 24. Due to space considerations in the text only version, emphasis of column headers were sometimes eliminated and some of the tables were rearranged. Produced from files generously made available by USDA through The Internet Archive. All resultant materials are placed in the Public Domain.