EFFECTS OF INDUSTRIAL WASTES 



The next question which demands consideration is the problem 

 of industrial wastes. 



Character of Trade Wastes 



Industrial wastes are the by-products of manufacturing processes 

 and are as varied in character as the industries themselves. They 

 are relatively speaking a new factor in the relations between man 

 and the natural environment. Starting not so very far back in 

 history, they have risen in most recent years with startling rapidity 

 to volumes that are proportionately large in comparison with the 

 flow of the streams into which they are discharged. Because of 

 their varied character, nearly every one of these industrial wastes 

 offers a special individual problem, making it difficult to speak of 

 them in general terms and ultimately demanding each its appropriate 

 treatment for the correction of the evil. Furthermore, because of 

 their very newness, their composition is unknown, as well as their 

 action on living organisms. Nevertheless there are certain features 

 which have been observed so often that they can be discussed as 

 general characteristics of this type of materials. 



Effects of Mixing Trade and Domestic Wastes 



Serious difficulties have been introduced into the problem of 

 stream pollution by the mixing of trade wastes with domestic 

 sewage. It was never calculated that any system of city sewers 

 should collect and discharge such wastes. Estimates of the character 

 and significance of city sewage discharges are regularly based on 

 the assumption that they contain the human and animal discharges 

 produced in a community of the specified size, and the system 

 provided for is based on these calculations. It needs only very 

 meager and superficial observations to determine that in fact the 

 sewage flow receives constant and not inconsiderable increments in 

 the form of trade wastes. Small manufacturing plants, machine 

 shops, laundries, garages and all sorts of other establishments 

 creating oil, gasoline, alkaline, and chemical wastes have established 

 direct connections with the sewers and pour into them without 

 modifications all materials they desire to be rid of. As the city 



