IV-385 



Sewage treatment reduces and alters the impact of municipal waste 

 on the environment. Primary treatment with chlorination removes 

 part of the decomposable organic material, removes nearly all of 

 the settleable and suspended solids, and almost eliminates the 

 possibility of pathogens in the effluent. Secondary treatment 

 can almost eliminate decomposable organic material, and some 

 special processes can eliminate certain dissolved salts. About 

 half the municipal wastes discharged to estuarine waters receives 

 secondary treatment, with the most extensive use of secondary 

 treatment being in the Chesapeake Bay estuarine region. 



INDUSTRIAL WASTES 



Associated with the major metropolitan developments are large 

 numbers of Industrial complexes with their attendant waste products. 

 Many of these wastes, especially from the chemical and petroleum 

 industries are so complicated that it is difficult both to 

 identify them and to assess their effects on the receiving streams. 



Table IV. 3.2 gives a summary of the major manufacturing industries 

 in the estuarine zone. Table IV. 5. 6 presents the basic character- 

 istics of wastes from each major industrial category. Table IV. 5. 7 

 and Table IV. 5. 8 show the waste discharges and levels of waste 

 treatment associated with this industrial development. 



