. Preventive medicine and hygiene. urification Processes.—Sub-surface Ireigation.—For small instal-lations a satisfactory method of disposing of sewage after sedimentationis to discharge it through 3-inch or 4-inch tile pipes laid in the ground10 to 18 inches deep in rows 2^/2 to 3 feet apart. In sandy soils thismethod gives satisfaction, and under favorable conditions the sewageof 150 to 250 people can be applied to an acre, the rate of applicationbeing commonly one to two gallons per lineal foot, or 20,000 to 30,000gallons per acre daily. With tight soils larger areas are clay
. Preventive medicine and hygiene. urification Processes.—Sub-surface Ireigation.—For small instal-lations a satisfactory method of disposing of sewage after sedimentationis to discharge it through 3-inch or 4-inch tile pipes laid in the ground10 to 18 inches deep in rows 2^/2 to 3 feet apart. In sandy soils thismethod gives satisfaction, and under favorable conditions the sewageof 150 to 250 people can be applied to an acre, the rate of applicationbeing commonly one to two gallons per lineal foot, or 20,000 to 30,000gallons per acre daily. With tight soils larger areas are clay soils the method cannot be used. This method of sewage disposal is particularly applicable to subur-ban and rural conditions. Begad Ieeigatiox.—^Broad irrigation consists in the application of PUEIFICATIOX PROCESSES 967 crude sewage to land, making it serve as food for crops, the principalvalue, however, being in the water itself. It is distributed by meansof ditches and other channels as in ordinary irrisration. The sewaffe. Fig. 123.—Chemical Precipitation Plant at Wohcester, Mass., Outlet. farms of Berlin and Paris are very extensive, the Berlin farms coveringnearly 20,000 acres. The rate of application varies from 3,000 to 15,000gallons per acre daily, an acre serving for the sewage of from 100 to300 persons. The crops raised on sewage farms frequently pay the
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Keywords: ., bookauthorwh, bookcentury1900, bookdecade1910, booksubjecthygiene
