454 



FUNDAMENTALS OF AGRICULTURE. 



.FRESH PIR VENT 



^SETTLING CHRMBER 

 THNK 



SIPHON CHRMBGR 



JD 



GRTE CHHMBER 



vals on a filter bed of gravel. In this case, a variety 

 of bacteria requiring air purifies the sewage by oxida- 

 tion. The settling tank for the aver- 

 age family should hold 125 to 200 

 gallons. Due provision should be 

 made for removing the solids which 

 settle in the tank at least once in two 

 years. The filter bed should be about 

 three feet wide and twenty feet long. 

 It is made up of sand and gravel of a 

 depth of about two feet. 

 At the bottom of the bed 

 is a drain tile to care for 

 the purified sewage. With 

 this system, a syphon is 

 necessary to discharge the 

 sewage on the bed at in- 

 tervals, otherwise the bacteria would 

 be drowned. A sewage disposal plant 

 can best be made of concrete in which 

 case an average cost at this time would 

 be about $60. The settling tank may 

 be made of three barrels placed end to 

 end, in which case the cost may be re- 

 duced to $25. 



The latter system on account of the 



HOW THE SEWAGE i 1 J J L 



MAY BE TAKEN syphon is more complicated, and has 

 CARE OF AF- not in all cases proven satisfactory for 

 P r i vate systems, although it has been 

 eminently successful for towns and 

 small cities. In any case it should be 

 remembered that a sewage disposal plant must have 

 some care and attention if it is to give the best re- 

 sults. 



Note : Typhoid fever is often caused by drinking 

 water, which is contaminated by seepage from the out- 

 buildings. In every community where typhoid fever 

 prevails an investigation of the sewage disposal should 

 be made. 



SEPTIC TANK. 



