PRODUCTION AND NUTRIENT ACCUMULATION BY PERIPHYTON IN A WASTE-WATER TREATMENT FACILITY

Five growth experiments were conducted over a 15-month period to quantify biomass, seasonal growth rates, and production of a periphyton community in the secondary clarifier of wastewater treatment plant. A maximum periphyton biomass of 130 g.m-2 (ash-free dry weight) was achieved during fall. Growth rates of approximately 0.23.d-1 (from chlorophyll a) were observed during spring, summer and fall. Winter values were also high (0.20.d-1). Maximum production was approximately 22 g.m-2.d-1 during spring. Periphyton phosphorus and nitrogen content was variable ranging from 0.4-2.4 nd 4.4-15.1%, respectively. Estimated maximum removal rates of both nutrients were high (up to approximately 160 mg P.m-2.d-1 and approximately 1900 mg N.m-2.d-1). High productivity and nutrient removal rates in this lotic hypereutrophic ecosystem may warrant further investigation and periphyton as a tertiary biological wastewater treatment in cold climates.