136 DAIRY AND FARM SEWAGE 



SEWER CONNECTION TO SEPTIC TANK 



Sewer connection from the cow barn to the septic tank should 

 be constructed of not less than five-inch glazed sewer pipe, and 

 preferably six-inch pipe. The sewer should be connected di- 

 rectly with the gutters and allowed to enter into a trap, as shown 

 in designs herewith. This trap is a small box, in which a pipe 

 bends down into the liquid to prevent the gases or odors coming 

 from the septic tank from going into the stable. Similar traps 

 should be put in when connected with the gutters of a creamery or 

 cheese factory, or to the house or dairy house on the farm. The 

 diameter of the sewer pipe from the house need not be more than 

 four inches, and may connect with the same tile as that coming 

 from the dairy barn. 



THE SIZE OF SEPTIC TANK AND IRRIGATING SYSTEM 



The size of the septic tank depends somewhat upon the amount 

 of sewage run through the tank and the consistency of the sew- 

 age. For average conditions the last two compartments should 

 hold the average discharge in twenty-four hours, and the irriga- 

 ting system should be of equal capacity to hold the sewage from 

 this compartment. However, the larger the tank the greater will 

 be the chance for fhe organic matter to thoroughly decompose, 

 and at the same time the irrigating system can be of greater ca- 

 pacity, irrigating a larger tract of land. For an ordinary farm a 

 septic tank of such capacity as shown in Figs. 5 and 6 will handle 

 the average dairy farm, creamery, or cheese-factory sewage. 



NECESSITY OF COMPARTMENTS 



Since the decomposition of the sewage depends upon the action 

 of bacteria, it is essential in order to have the process go on effect- 

 ively that the germs should not be disturbed to any great extent. 

 Sewage, as a rule, when it comes from the house or dairy barn, 

 runs into the tank with a rush, which has a tendency to roil the 

 sewage in the tank. To overcome this sudden rush a partition 

 should be put across the septic tank close to the inlet of the tank, 

 which is supposed to prevent the disturbance in the second, third 

 and fourth compartments. However; it is quite impossible to 

 regulate the force of sewage in such a manner as to prevent any 

 disturbance in the second tank. For this reason it is advisable to 

 put a third partition in the tank, which will give the germs a 

 chance to act thoroughly upon the sewage before it enters the dis- 

 charge tank, or last compartment. 



As the sewage travels from one tank to another it is gradually 

 purified, and as it flows into the discharge tank all organic matter 



