48 DISEASES OF CATTLE, SHEEP, GOATS, ETC. 



itself by the increased crop production which resulted from irri- 

 gating and fertilizing the soil. It is authentically stated that a hor- 

 ticulturist in Ohio has grown enough berries on his irrigated and 

 fertilized soil in one year to pay for three such sewage disposal 

 plants. 



Construction of a Septic Tank. There are numerous ways for 

 building septic tanks. Such tanks may be built of any tank ma- 

 terial, but for durability it is preferable to construct them of brick, 

 stone, or concrete. The partitions may be built of concrete or wood. 

 It is generally advisable to build them of concrete if convenient to 

 do so. The tank should be built as nearly air-tight as possible, with 

 a slight vent of one-half inch pipe to allow the gas to escape. There 

 should be a trap door in the first compartment so as to allow the 

 same to be cleaned when necessary. The partition should be built 

 in such a way as to allow the water to be taken from the center of 

 the tank, where the sewage is all liquid. The most of the solid par- 

 ticles of sewage either sink or float; consequently, by taking the 

 sewage from the center of the basin only such liquid and particles 

 as are of a semi-solid nature, or have the same density as water, are 

 discharged into the second compartment. Decomposition is carried 

 on still further in this compartment. When transferred to the third 

 compartment it should be thoroughly liquefied. When transferred 

 to the fourth compartment it is ready to be deposited into the irri- 

 gating system, where it is to be taken up by the soil. If the sewage 

 is not to be utilized for irrigating purposes, but drained directly 

 into a stream, the sewage may 'be taken from the top of the tank. In 

 case the tank is to be cleaned, the plugs of the same systems may be 

 removed and thoroughly drained. For irrigating purposes it is ad- 

 visable to use a siphon. This siphon removes the water from the 

 last compartment of the septic tank automatically at intermittent 

 discharges. The discharge at one time of a quantity of sewage large 

 enough to fill the irrigating system will scour the system of pipe; 

 besides it more uniformly distributes the sewage throughout the 

 whole irrigating system. Without a siphon, on pulling the plug 

 occasionally the same effect can be secured, but if the sewage is al- 

 lowed to overflow into the tile it will run out into the soil nearest to 

 the septic tank. In the latter case the soil will become over-saturated 

 with the liquid, and the purification of the sewage in the soil is 

 thereby rendered imperfect. 



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 directly with the gutters and allowed to 

 enter into a trap. 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, 



