TREATMENT OF FARM SEWAGE. 



8 9 



It is very easy for the farm to make use of the principles of a septic 

 tank in caring for and even utilizing its sewage. Fig. 19 shows 

 diagrammatically a means of accomplishing it efficiently and at 

 comparatively small expense. The diluted sewage from the house 

 is conducted to a tank sunk in the ground at any convenient distance. 

 The tank should be of such a size that it will hold the entire sewage 

 for twenty-four hours. If each person uses twenty gallons of water 



Pmtetefc etc. 



Mtrates (/nscib) 



FIG. 20. The nitrogen cycle. 



per day, the tank for a household of ten should be three feet deep, 

 two feet wide and six feet long. It must be covered so as to exclude 

 air and light, and the sewage must flow slowly and quietly through 

 the tank, thus making it a septic tank. The discharge frorm the 

 tank is best received into a second tank from which it can be 

 conducted to a stream or upon the garden for fertilizing and 

 irrigating it. 



