SANITATION 391 



by the liquid freezing in the ditch, thus closing the outlet. 

 It is therefore desirable to get an outlet in as favorable a 

 location as possible; if there is not plenty of room for the 

 liquid to flow out and freeze without backing into the tile, 

 it is well to cover the outlet with straw or coarse manure. 

 Where the outlet is in a ditch that drifts full of snow no 

 difficulty is experienced from freezing, as the liquid will 

 disappear under the snow. Ordinarily no trouble has been 

 experienced from freezing in the tile until it has frozen up 

 in the open ditch and the ice has become so high that the 

 liquid cannot flow. After that the liquid backs into the tile 

 and freezes. While the sanitary condition of the effluent 

 discharged in the final outlet is not so good as that discharged 

 when either of the other methods hereafter described is used, 

 it ordinarily will not become a nuisance around the outlet, 

 even though the outlet ditch is dry part of the season, unless 

 the tank is worked beyond its limit or there is a number of 

 tanks outletting at one point. A small tank discharged 

 for six years, through an outlet of this kind, into an open 

 ditch only 300 feet from a residence alongside a public 

 road and did not become a nuisance. 



Absorption method. The second method is known as the 

 absorption method. In this method the liquid is carried 

 from the tank through a drain with water-tight joints, until 

 it reaches a distribution system which consists of tile laid 

 with open joints, such that the liquid can pass through and 

 be absorbed by the soil. The more open and porous the 

 soil, the more satisfactory is this method of disposal. A 

 very compact, tight soil which does not permit water to 

 pass through it readily, or a soil that becomes saturated with 

 water during rainy periods, would not be a satisfactory one 

 for this system. 



The absorption system, shown in Figure 304, can be 

 located at any desirable distance from the tank. There 

 necessarily must be fall enough so that the liquid will readily 

 flow from the tank to the system. The tile should be laid 



