MODIFICATIONS TO THE IAWPRC TASK GROUP GENERAL ACTIVATED-SLUDGE MODEL

The general activated sludge model proposed by the IAWPRC Task Group on modelling of the activated sludge system represents a truly fundamental approach to modelling and design of biological treatment systems. Modifications to the model have attempted to further refine the model to more accurately simulate the biological processes. Further research into the behaviour of activated sludge systems incorporating biological phosphorus removal have demonstrated that further refinement of the model is required with particular reference to denitrification kinetics in the primary anoxic reactor of the Modified UCT system. A modification to the IAWPRC model is proposed which permits predetermination of denitrification rates. Extension of this modification may well provide insight into the effect of ''selectors'' on activated sludge systems and the varying specific growth rates measured for both heterotrophs and autotrophs.