Effect of Temperature on Effluent Quality in a Biological Wastewater Treatment Process

Abstract

Abstract In the present study, the temperature effects on the organic carbon and nitrogen removal in an activated sludge process are evaluated. Benchmark Simulation Model No.1 (BSM1) based on activated sludge process is used for all the simulation purposes. A steady state simulation is performed to analyze the effluent concentrations with varying kinetic parameters obtained from different temperature coefficients over a wide range of temperatures from 15 °C to 35 °C. The temperature coefficient ‘a’ is assumed to have different set of values specific to the kinetic parameters, namely, Maximum heterotrophic growth rate μ m H \left( {{\mu _{mH}}} \right) , Maximum autotrophic growth rate μ m A \left( {{\mu _{mA}}} \right) , Heterotrophic decay rate b H \left( {{b_H}} \right) , Autotrophic decay rate b A \left( {{b_A}} \right) . The effluent concentration defined in terms of Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Total Suspended Solids (TSS), Total Nitrogen (TN) and Ammonia are observed to be significantly changing with a change in the kinetic parameters which are in turn a strong function of temperature coefficient. Emphasis is laid on the temperature range of 25–30 °C as it is commonly the most operated temperature range in a WWTP in India. It is also noticed that at temperatures <20 °C and >30 °C, the effluent limitations are violated from the standard values.