A numerical approach to activated sludge kinetics

Abstract

Mass balance equations for biomass and substrate are numerically solved to determine the effects of different variables on suspended growth systems. Dimensionless quantities and computer techniques are used to express the results generally. Monod kinetics and reactors-in-series principles are applied to explain variations in axial dispersion and waste-water quality experienced in real systems. An attempt has been made to determine the effluent concentrations as a function of two parameters, i.e. a dimensionless time and a dimensionless substrate concentration (of the incoming waste-water). The computer results have been generalized in the form of design tables. An available approximate method for plug-flow reactors has been compared with the solution obtained in this way, and the resulting error has been demonstrated. In this study, results obtained from large numbers of reactors-in-series are reported to characterize plug-flow conditions. Performance of reactors subjected to varying degrees of axial dispersion will be stressed in a subsequent paper.