392 



ENGINEERING ON THE FARM 



practically level, and, since the air is of great assistance in 

 purifying liquids, should not be over 10 or 12 inches deep. 

 The liquid should reach the distributors in intermittent dis- 

 charges, so that it will fill the entire system to the same depth 



" ' ■ I I I I I T- 



^ 

 \ 



frosr? 



TcnJr 

 Off/fit 



6' 



* 



i ■ ■ » ■ ■ ■ ■ 



After University of Minnesota 



Fig. 304. Arrangement of open-jointed tile for an absorption system, with 

 the addition of a drainage system laid around the outside 



in a short space of time. The flow of liquid should then 

 cease, and the distributors will empty themselves by absorp- 

 tion into the soil. They should then stand a short time before 

 being refilled. For the private house a discharge from the 

 tank approximately once in twenty-four hours is satisfactory. 

 The distributing drains can best be made from ordinary 

 4-inch drain tile. Since such a tile holds approximately 



