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Environmental Science/Phosphate and activated sludge


At what concentration does phosphate adversely affect an activated sludge waste water treatment system?  (The phosphate is used in potable water treatment.)

Some phosphate is required for an activated sludge system. In fact, a number of systems have been designed to uptake excess phosphate in the intake to the AS system, thereby reducing the concentration of phosphate in the POTW effluent. Mostly, it really doesn't harm the AS System but serves as a residual source of oxygen in anaerobic conditions.
The phosphate is generally in the PO4 form, and certain processes are designed to become anaerobic and that reduces the PO4 to P, where it is better handled by the AS system. Also, it's better precipitated by any of a number of chemical treatments.
Ideally, the C:N:P ratio for Activated Sludge is about 100:20:1, so some P is necessary it's the excess which is a nuisance.
The problem is the receiving body of water.  A phosphate concentration of 0.2 mg/l in the receiving stream has been identified as a potential source or cause of algal blooms. Many POTW's have effluent limits of 0.05 mg/l of Total P.  

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David L. Russell, PE


I`m a Chemical,Civil and Environmental Engineer and have a number of projects in all phases of the environment. I have worked in the chemical industry and am active in professional societies, and am currently on an industrial wastes committee for the Water Environment Federation, and have taught courses in remediation in the US and abroad. I have written one book on Remediation of petroleum Contaminated Sites, and have a second book on PRACTICAL WASTEWATER TREATMENT to be published by John Wiley in September, 2006. I've also written over 30 articles on various elements of environmental problems and cleanup. Most Recently, I have addressed a NATO Scientific and Techical Conference on Ecoterrorism, and have worked with the same group on remediation of sites contaminated with Chemical Warfare Agent materials and othe materials as well. . I can answer q`s about Chemical and Environmental Engineering, land development, air pollution, water pollution, soil and water cleanup, combustion, international environmental problems, industrial processes chemical processes. Civil and Environmental and Chemical Engineering. Overall, I have over 35 years of experience in this area. Note: I do not answer homework questions


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