134 



DAIRY AND FARM SEWAGE 



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 nec- 

 essary. 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 sew- 

 age is all liquid. The most of the solid particles of sewage either 



roi?-CQJ3 M - OR. ENAMEL R^- 



FIG. 7.- Showing- the detailed construction of a round septic tank which can be con- 

 nected with a summer and winter system of sewage disposal. This tank can be used where 

 the sewage is more liquid than in the case of tank in Fig. 5. 



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 fur- 

 ther in this compartment. When transferred to the third com- 

 partment 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 sew- 

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



