191T1 EURAL EKGINEEBING. 589 



" Not only do the actual wash waters cause nuisances, but in a practical way 

 also whey, buttermilk, and skimmed milk remaining at the end of the day's oper- 

 ation, all three of which require extended dilution to admit of their satisfactory 

 disposal in running streams. ... No practical process appears available for 

 whey treatment unless the small plant ships the waste to a central station for 

 evaporation. Whey-butter making would, of course, remove but little of the 

 organic matters of the whey. Whey contains so much albuminous matter as to 

 render ineffective the bacterial processes availed of in the treatment of the other 

 wastes of the dairy industry and its removal by cartage appears the most practi- 

 cal method of disposal at present available. . . . Dependable whey disposal in a 

 practical way means definite provision for its systematic removal through such 

 part of the year as dilution disposal in the local stream can not be employed. 



" Tank treatment by septic tanks requires land or artificial filters in the 

 absence of 30-fold dilution. With proper construction . . . tanks of 48 or 72 

 hours' retention, according to the character of the processes carried out at the 

 plant, and filters of sand on a basis of 25,000 gal. per acre per day, can be de- 

 pended upon to prevent nuisances. The rectangular tank has at best certain 

 disadvantages, particularly as regards the intermittent discharge of sludge 

 with the effluent. Data are too few to indicate the applicability of two-story 

 tanks, but it would seem that such tanks can be advantageously used for wastes 

 of the dairy industry, subject to proper construction details, especially as to 

 detention period. Combined septic and two-story tanks may solve this problem 

 to good advantage. . . . 



" Tanks remove suspended matter, increase acidity by encouraging the lactic 

 fermentation, and to a certain extent modify the chemical character of these 

 wastes. Filters, subsurface tile systems, or running streams supply the oxygen 

 essential to render the organic matters of these wastes no longer amenable to 

 putrefactive decomposition. Each has its own function to perform. These 

 processes cover the field at present available for waste treatment. All methods 

 applicable to the treatment of domestic sewage have been applied in the past 

 with varying degrees of success to dairy wastes, and it is possible that the 

 activated sludge process may find in these wastes a fruitful field. Unless 

 activated sludge methods will result in by-product recovery, bringing financial 

 gain to the plant, it is the author's viewpoint that the process would be of 

 limited utility because the operation of such plant would involve a daily expense 

 and because dairy waste disposal to be successful under practical conditions 

 must be cheap and simple in operation and require but little daily attention." 



Forty-two references to literature bearing on the subject are appended. 



Sewage disposal on the farm, G. M. Wabeen (U. S. Dept. Agr. Tearbook 

 1916, pp. 3Jf7-S73, figs. 10). — This article deals with sewage as a menace to 

 health and with sewage purification by natural agencies, and describes and 

 diagrammatically illustrates pit, dry earth, and wet closet privies, chemical 

 closets, cesspools, and septic tanks. 



An especially Important point brought out regarding septic-tank systems is 

 that " the septic tank is not a complete method of sewage treatment. With the 

 general run of small septic tanks it is close to the facts to say that of all the 

 solid matter in the crude sewage one-third is reduced to liquids and gas, one- 

 third remains in the tank, and one-third escapes with the effluent. Every septic- 

 tank installation is a problem by itself. As a suit is fashioned to the size and 

 needs of an individual, so should the design of a septic tank and the after dis- 

 position of the effluent be decided upon, with full consideration for the size of 

 the family, the amount of water used, the location of property lines, buildings, 

 wells, and drainage outlets, the slope of the land, and the character of the soil 

 and subsoil." 



