THE PRACTICAL LIMITS OF PHOSPHORUS REMOVAL: HOW LOW CAN YOU RELIABLY GO?

While phosphorus removal from municipal wastewater is now routinely required to meet stringent discharge standards, little information has been published showing the reliability and long-term effectiveness of different treatment technologies, especially at low concentrations. Full-scale performance and reliability was analyzed for U.S. plants using chemical, physical, and biological treatment technologies. Chemical treatment and biological treatment reliability could be improved by use of filtration, and by use of the technologies in combination. The highest reliability was observed with a facility using chemical and biological treatment followed by application to soil. In general, the coefficient of variation increases and reliability decreases as the target effluent limit decreases.