1. Ramalho, R. S. (1983),Introduction to Wastewater Treatment Processes, 2nd ed., Academic, New York.
2. Federal Register, Federal Water Pollution Control Act of 1972 (PL 92–500).
3. Federal Register, Federal Water Quality Act of 1987 (PL 100–4).
4. US EPA, Sept. (1979),Process Design for Sludge Treatment and Disposal, EPA 625/1-79-011, Environmental Research Information, Cincinnati, OH.
5. Reed, S. C, Middlebrooks, E. J., and Crites, R. W. (1988),Natural Systems for Waste Management and Treatment, McGraw-Hill, New York.