Modelling biological phosphorus and nitrogen removal in a full scale activated sludge process

A previously derived metabolically structured model for the biological aero bic and anoxic phosphorus removal was combined with the ASM no. 1 and teste d in its capacity to describe a full scale biological nitrogen and phosphor us removal WWTP. The sensitivity of the effluent concentrations and the slu dge production towards the stoichiometric and kinetic coefficients, the inf luent composition, the set-up of the hydraulic model and the flows of air, mixed liquor and return sludge was analysed. This showed that besides a lim ited number of model parameters (12%) the influent characterisation influen ced the model output significant. For calibration of the model only 3 out o f the 60 default parameters together with the unknown air input needed to b e changed approximately 40% to describe the measurements of soluble compone nts at different places in the full scale WWTP as a function of time. The c hoice of parameters to calibrate was done on the basis of process and model knowledge rather then on the sensitivity analysis. For the calibration the in-process measurements were much more informative then the effluent measu rements. (C) 1999 Elsevier Science Ltd. All rights reserved.