Production and Nutrient Accumulation by Periphyton in a Wastewater Treatment Facility1

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 a 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 and 4.4–15.1%, respectively. Estimated maximum removal rates of both nutrients were high (up to ∼ 160 mg P·m−2·d−1 and ∼ 1900 mg N·m−2·d−1). High productivity and nutrient removal rates in this lotic hypereutrophic ecosystem may warrant further investigation of periphyton as a tertiary biological wastewater treatment in cold climates.