The Sewage Tank. 



The tank in the sketch is of sufficient size to take care of any- 

 ordinary farm home sewage, and is 7 feet long, 3^/2 feet wide 

 and 6 feet deep, these being inside dimensions; the side walls 

 should be made 8 inches thick, the bottom 5 inches and the top 

 6 inches thick. If the tank is placed under a lawn or grassland 

 where there is no heavy teaming over it, it will not need any 

 reinforcing, but if placed beneath a driveway the top only 

 should be reinforced. The manhole cover should be placed in 

 one corner so as to enable you to remove the lumber you use 

 for concrete forms without cutting it. The tank should be 

 placed so that it is covered with at least 18 inches of soil, and 

 then it will never freeze up. It must also be placed in such a 

 way that the 6-inch inlet pipe has a good grade or slope to the 

 tank, so that the water will have velocity enough to keep the 

 pipe free at all times. You see the ends of the inlet and outlet 

 pipes are submerged, which is done to exclude air and to pre- 

 vent the breaking up of the scum on the surface of the contents 

 of the tank, which acts as a sort of protective blanket for the 

 bacteria. 



The contents of the tank should be kept as quiet as possible, 

 and as an aid in this matter we place a baffle board across the 

 tank as shown. This baffle should rise a few inches above the 

 surface line and have an open space 18 inches below it, to 

 allow the heavy portion or sludge to spread over the whole 

 bottom of the tank, where I believe it will be better taken care 

 of by the bacterial action than it would in a smaller area. 



Of course the 6-inch outlet pipe where it leaves the tank 

 regulates the height of the material within, and is for the pur- 

 pose of conducting the surplus water or effluent away to the 

 place where it is finally disposed of. The outlet pipe should be 

 set so as to allow an 18-inch air space above the flow or surface 

 line. 



Now as to the methods of disposing of the effluent. If you 

 have to consider the protection of a water supply, as well as to 

 dispose of the overflow, then you must conduct the effluent 

 away to a point at least 200 feet from your own or a neighbor's 

 water supply or any pond or stream connected with a supply. 



