The City of Windsor currently provides physical-chemical primary treatment for one of its two plants, the West Windsor Pollution Control Plant, which discharges directly to the Detroit River which feeds into Lake Erie. The plant currently discharges a relatively good effluent, 35 mg/l BOD, 20 mg/l SS, 0.75 mg/l P, and the effluent is not acutely toxic to aquatic biological testing. However, it is anticipated that the Municipal Industrial Strategy for Abatement (M.I.S.A.) will be directing all of the remaining 23 municipal “primary” plants in Ontario, with a priority on those discharging to the Great Lakes, to upgrade to at least biological secondary treatment in the near future. The City undertook an 18 month pilot study to evaluate alternative wastewater treatment processes to achieve lower capital and operating costs compared to conventional treatment. It was also believed that the information learned from the processes tested would have direct applicability to the other primary plants that would have to be upgraded.