BACTERIAL PURIFICATION 



259 



The changes occurring in the tank are complex. From 

 analyses by myself and others it appears that the total dis- 

 solved solids are increased somewhat, but not in relation to the 

 organic debris that has passed into solution. A large propor- 

 tion has undergone the hydrolytic decomposition, producing 

 nitrogen, methane, a small quantity of hydrogen, ammonia, 

 and carbonic acid. The result is the production of a large 

 quantity of inflammable gas, which according to Clark amounts 



Diagram of Overflow Pipes. 



--^\. 



-f Gear 



Diagram showing successive states of Filters corresponding to successive positions of 



alternating gear. 



Fig. 28. — Working of Cameron's Automatic Gear. 



to half a cubic foot per 100 gallons of sewage, and as previously 

 mentioned, has been successfully utilized. 



A few explosions have occurred through the ignition of the 

 tank gas. Except near houses or highways, tanks are now 

 usually either left open, or are covered with light iron roofs. 



The ammonia and the major part of the CO2 remain in the 

 solution, which contains on an average 33 per cent, more of 

 free NH3, 29 per cent, less of organic matter as measured by 

 the oxygen consumed, and 46 per cent, less of albuminoid 

 ammonia. If we knew the nature of all the bacterial changes, 



17 — 2 



