STEADY-STATE ANALYSIS OF THE COUPLING AERATOR AND SECONDARY SETTLING-TANK IN ACTIVATED-SLUDGE PROCESS

The steady state analysis of coupling the function of aerator and seco ndary settling tank in activated sludge process for wastewater treatme nt is carried out to obtain appropriate responses of output variables and to decide optimum operating parameters. To consider the effect of the secondary settling tank, limit flux theory is applied and the aera tor is assumed to be a continuous flow stirred tank reactor. By using sludge recycle ratio and sludge waste ratio as the operating parameter s, the responses of the output variables - biomass concentration in ae rator, dissolved pollutant and solid concentration in effluent - are r epresented as response surfaces and isoresponse curves. Acceptable ope rating zone can be obtained from the curves and optimum parameters can be determined. Coupling the function of aerator and secondary settlin g tank is important to consider the appropriate control of an activate d sludge process. Copyright (C) 1996 Elsevier Science Ltd