CREAMERY BUTTER MAKING 147o 



The sewage becomes gradually purified in its passage 

 through the tank, and as it flows from the last section it is 

 nearly as clear as water, but has a slightly sour odor, 

 which it seems to retain and which is in no way objection- 

 able. The puriried sewage has been kept for weeks with 

 no sign of the development of putrefactive odors. 



The discharges should be arranged as shown in Fig 2. 

 This arrangement will cause the least mixing of old and 

 new sewage. There is no discharge from A into B until 

 the second day's sewage flows into A. Similarly there is 

 no discharge from B into C until the second discharge 

 into B, etc. The sewage, therefore, requires from three 

 to four days in its passage through the tank. 



While a double partition tank is recommended here, 

 the writer has secured satisfactory results with a single 

 partition, though it was found that a much larger tank 

 was necessary than where two partitions are used. 



Cost of Tank. A double partition tank, 12 feet square 

 and 4 l /2 feet deep, constructed of concrete ( i part cement 

 and 4 parts sand) five inches thick, will cost approxi- 

 mately as follows : 



Digging $6.00 



7 Barrels cement 14.00 



5 loads of sand (delivered) 5.00 



Laying concrete 5 .00 



6 3-inch elbows 4.00 



20 feet of i-inch gas pipe (for vent) , 2.00 



30 feet of 1 1 /2 -inch gas pipe (for water from 



cream vats, etc.) 4.00 



Q feet of 3'inch gas pipe (for discharges) 2.50 



2-inch planks (for cover) 5.00 



Total , $47-50 



