Recently, effluent total phosphorus (TP) concentrations lower than 0.10 mg/L are being proposed for expanded or new WWTPs in Ontario in order to meet the MOE Policy 2 requirements for surface water quality. For example, expansion of the Regional WWTP serving the Town of New Tecumseth will require that the Regional WWTP achieve an effluent TP concentration of 0.07 mg/L (Abraham et al, 2003). Similar or lower effluent limits are expected to be imposed on the expanded Innisfil WPCP (Stantec, 2004) and Bradford WWTP (Stantec, 2004). Pilot scale and demonstration scale studies have shown that these levels of phosphorus removal are achievable; however, there is no full-scale operating experience in Ontario to show that these low levels of phosphorus removal are achievable on a consistent basis.

XCG and Stantec conducted a review of the phosphorus removal capability of WWTPs in other jurisdictions to assess the capability of full-scale WWTPs to consistently achieve very low effluent TP concentrations and the technology in use elsewhere to accomplish this level of treatment. This review identified several WWTPs in the United States that are reportedly achieving effluent TP concentrations of 0.1 mg/L or lower on a consistent basis. Notably, three Colorado WWTPs reported achieving effluent total phosphorus concentrations of 0.01 mg/L on average, while a WPCP in Virginia has reportedly produced an effluent TP concentration of 0.053 on average. A review of the process configuration and performance of these facilities is provided.