Calibrating simple models for mixing and flow propagation in waste water treatment plants

Mathematical models are useful tools in the prediction of system responses to operational changes in waste water treatment plants (WWTPs). The tanks-i n-series model is one of the widespread hydraulic models in waste water tre atment. This study shows the applicability of the mentioned model. Next to the mixing of substrate in a conventional activated sludge system, an oxida tion ditch and a trickling filter, also the flow propagation in a waste wat er treatment plant was modelled. These different full-scale examples taken from waste water treatment demonstrate the relative ease of model configura tion and calibration. Difficulties like experimental design, modelling the diffusion in biofilms and transients in flow rate were encountered. (C) 199 9 IAWQ Published by Elsevier Science Ltd. All rights reserved.