Control of an alternating aerobic-anoxic activated sludge system - Part 1:development of a linearization-based modeling approach

A two-phase model (linear in each phase) is developed for an alternating ae robic-anoxic completely mixed activated sludge process for the removal of c arbonaceous substrates, nitrification, and denitrification. The linearized model is adapted from the activated sludge model No. 1 (ASM1) originally de veloped by the International Association on Water Pollution Research and Co ntrol. The modified dynamic model captures the essential process features o f ASM1 while dramatically reducing demand on computational resources. Simul ations may be conducted in such short times that the simplified model is su itable for inclusion in on-line optimization-based process control schemes. Calibrated model parameters are within the ranges specified in ASM1. Compa rison of model predictions with experimental measurements from two differen t sets of bench-scale alternating aerobic-anoxic reactors indicates reasona ble prediction accuracy of the model; further compensation for inaccuracy i s achievable by introducing a feedback loop. (C) 2000 Elsevier Science Ltd. All rights reserved.