On the modelling and simulation of a BNR activated sludge process based ondistributed parameter approach

A computational algorithm based on an orthogonal collocation approach is de veloped to simulate a BNR activated sludge process consisting of anaerobic, anoxic and aerobic zones in a back-to-back scheme. The hydraulic model emp loyed in this study considers backmixing or intermixing, which can represen t the actual process more accurately than the idealised flow schemes common ly employed for modelling and/or design of the activated sludge bioreactor. The kinetic model of the International Association on Water Quality (IAWQ) - Activated Sludge Model No. 2 (ASM No. 2) was reduced to submodels repres enting the anaerobic, anoxic and aerobic zones. Validation of simulated res ults against pilot-scale experimental data suggested that the new computati onal algorithm is able to predict the behaviour of components of interest r easonably well despite uncertainties with processes and parameters related to phosphorus accumulating organisms. Predicted transient properties may be gainfully employed for improvement to the operation and control of the pro cess. (C) 1999 IAWO Published by Elsevier Science Ltd All rights reserved.