MODIFICATIONS TO THE IAWPRC TASK GROUP GENERAL ACTIVATED-SLUDGE MODEL

The general activated sludge model proposed by the IAWPRC Task Group o n modelling of the activated sludge system represents a truly fundamen tal 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 biologic al phosphorus removal have demonstrated that further refinement of the model is required with particular reference to denitrification kineti cs in the primary anoxic reactor of the Modified UCT system. A modific ation to the IAWPRC model is proposed which permits predetermination o f denitrification rates. Extension of this modification may well provi de insight into the effect of ''selectors'' on activated sludge system s and the varying specific growth rates measured for both heterotrophs and autotrophs.