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The Problem of Sewage Purification in Indiana. 



P.y It. L. Sackett. 



CONDITIONS. 



As the population of a city increases, the difficulties of obtaining a 

 sufficient water supply which is free from contamination by sewage be- 

 comes more and more difficult. It is now a well established fact that 

 sewage-contaminated waters are to a considerable extent the cause of 

 summer complaint and other bowel troubles, besides the more dangerous 

 disease, typhoid fever. The extensive death rate among children is in 

 some measure chargeable to impure water. 



There are very few large cities that are able to obtain a ground water 

 of satisfactory quality and quantity. We are therefore driven to the use of 

 surface water. 



OBJECT OF SEWAGE PURIFICATION. 



Large volumes of sewage are discharged into the White, the Wabash 

 and Ohio rivers and their branches, also into Lake Michigan, by the cities 

 situated near them. In order to maintain a stream in a condition ap- 

 proaching normal purity, methods for the purification of sewage are ap- 

 plied, so that the resulting effluent discharged into a stream is purer. This 

 purification is obtained by some method of oxidation which will remove 

 the putrefactive material or highly organized food on which pathogenic 

 bacteria live. 



Sewage purification is a relative matter, and absolute purity of the 

 effluent is practically impossible and generally is unnecessary. The prob- 

 lem, then, is to adapt available means to the conditions in order to eco- 

 nomically defend the people against water-born diseases. 



Dilution may be considered a process of purification, and therefore 

 the larger the volume of pure water available in a stream the lower the 

 percentage of purification required, for wherever there is running water 

 not already contaminated, oxygen is present and some purification takes 

 place ; vegetation and sedimentation also assist. 



The old theory that a stream would purify itself in a flow of ten miles 

 was a dangerous one, because it depended distinctly on conditions. 



