PARK SANITATION 



859 



The automatic siphon consists essentially of a small tank equipped with a 

 U trap with the short leg of the U connected with the drain and the long 

 leg covered with a bell. The trap is filled with water, and as the effluent 

 from the septic tank flows into the siphon chamber the weight on the column 

 of water in the trap gradually increases until a portion is forced out into the 

 drain pipe. This starts the siphon and the liquid continues to flow out 

 until the pressure is equalized by the entrance of air under the bell. The 

 siphon chamber should have an overflow pipe connected with a drain to 

 carry away the effluent in case the siphon fails to function. It should also 

 have a manhole and a fresh air vent (Plate 335). 



The capacity of the siphon chamber should be such that the amount 

 of liquid discharged by siphonage at any one time will fill all the tiles of 

 the absorption field connected therewith. The capacity of the different 

 sizes of drainage tile per lineal foot is as follows: 



Diameter of tile Volume in gallons per 



in inches one lineal foot 



3 inches .367 



4 inches .652 



5 inches 1.02 



6 inches 1.46 



Thus an absorption field designed to dispose of the sewage produced by 

 twenty-five individuals, allowing fifty lineal feet of four-inch tile per person, 

 would have a capacity of eight hundred and fifteen gallons, or about one 

 hundred and thirty cubic feet of effluent. The siphon chamber supplying this 

 field should be so built that it will discharge this amount of effluent at one 

 time. For other than the smallest installations, two or more absorption 

 fields should be available, so that they may be dosed alternately and 

 overloading prevented. 



Where more than one absorption field is used the effluent passes from 

 the siphon chamber through a water-tight pipe to a diversion chamber 



PLATE No. 335 

 SEPTIC TANK WITH DOSING (SIPHON) CHAMBER AND ABSORPTION FIELD 



Shows method of ventilation. (Wisconsin State Board of Health.) 



