44 



BULLETIN 57, U. S. DEPARTMENT OF AGEICULTUEE. 



Tlio disposal system should be divided into at least two divisions 

 fur intermittent application, and the capacity of the system should 

 be 10 to 15 per cent larger than for a double-chamber tank system. 



The smgie-chamber septic tank system requires considerable at- 

 tention, since there is no provision for automatic discharge. Fig- 

 ures taken from the work of the Wisconsin Agricultural Experiment 

 Station show that in the long run there is little difference in the 

 cost of the single and double chamber tank system.^ 



C/./-7ANHOL£ 



OV LCTEL GROUND 

 ass TH/S OUTLET. 



c:t-:=nX=i:=t:^ 



TOP VI£VY. 



Fig. 36. — Single-chamber septic tank for six people. 



THE GREASE TRAP. 



The grease trap acts as a separator of the grease and sewage from 

 the kitchen sink or dairy room. If grease is allowed to enter the 

 sewer it accumulates and eventually clogs the system. 



Figure 38 shows a grease trap.^ Two large, glazed sewer tiles are 

 placed in the ground. The inlet is usually a 2-inch iron pipe. The 

 outlet must be so arranged that the mouth of it is at all times below 

 the surface of the sewage. The grease, being lighter, naturally 

 floats upon the water, and is thus prevented from entermg the out- 

 let. The outlet is made of 4-inch glazed sewer tile and is connected 

 with the sewer inlet of the septic tank. A concrete cover is pro^dded, 

 and grease and dirt which may accumulate are removed when 

 necessary. 



' Wisconsin Sta. Circ. Inform. 34. \ — , :;' 



