Disposal of House ticicage. 



299 



tern of drain tile aud permitting it to escape by percolation through 

 the soil as in Figs. 4 and 5. 



Where a sand filter is used and the discharge is on the ground sur- 

 face, it is necessary to construct the tank above ground unless its loca- 

 tion is on a side hill, and it would necessarily have to be at some dis- 

 tance from the buildings, as the filter should be exposed to the air and 

 the surrounding soil would be kept wet by seepage unless there is 

 underdrainage or running water. 



3r-a/r} Ti/e 4' 



J)ra'n T,/e 4 ' 



Fig-. 5. System of drain tile used in connection witii automatic valve. 



A tank arranged to discharge into a tile system, Fig 5, is more gen- 

 erally used for the individual houses than the sand filter. This method 

 requires chamber B to be fitted with an automatic valve as shown at B, 

 Fig. 4. This valve permits chamber B to fill with sewage, which would 

 require from 24 to 36 hours. When the chamber is full the valve 

 opens and the liquid flows out through a line of pipe to the tile system, 

 Fig. 5, where it is absorbed by the soil. This tile system is made of 

 ordinary drain tile with open joints. As the absorptive power of the 

 soil and the circulation of air through the soil decreases as the depth 

 increases, the tile should be laid not over ten or twelve inches in depth, 

 unless the soil is very porous. This tile system for proper distribution 

 of the liquid should be laid level, and the capacity of the tile for 

 holding liquid should be about ten per cent, larger than the capacity 

 of the valve chamber. The pipe connecting the valve chamber with 

 the tile system should have cemented joints to prevent leakage be- 



