MODELING COD, N AND P REMOVAL IN A FULL-SCALE WWTP HAARLEM WAARDERPOLDER DAMIR BRDJANOVIC* 1 { M , MARK C.M. VAN LOOSDRECHT 1M , PAUL VERSTEEG 2 , CHRISTINE M. HOOIJMANS 3 , GUY J. ALAERTS 3M and JOSEPH J. HEIJNEN 1M 1 Department of Biochemical Engineering, Faculty of Chemical Technology and Materials Science, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands; 2 Hoogheemraadschap van Rijnland, Breestraat 48, P.O. Box 156, 2300 AD Leiden, The Netherlands and 3 International Institute for Infrastructural, Hydraulic and Environmental Engineering, IHE Delft, Department of Environmental Engineering, P.O. Box 3105, 2601 DA Delft, The Netherlands (First received 1 January 1999; accepted in revised form 1 May 1999) AbstractÐIn this study the following was evaluated: (a) application of a complex activated sludge model on a full-scale plant (Phostrip 1 -like process), (b) in¯uent and sludge characterization procedures for bio-P modeling, (c) the use of batch tests for model evaluation and (d) dierent alternative BPR process con®gurations (A/O, UCT and BCFS 1 ). An integrated model for aerobic and denitrifying biological phosphorus removal (Delft bio-P model) replaced the module for P removal of ASM No. 2 and was combined with retained equations for COD and N conversion of the ASM No 2. This combined model proved well capable of describing the wastewater treatment plant (wwtp) Haarlem Waarderpolder with adjustment of only three (out of the sixty) default parameters. Some of batch tests were satisfactorily described by the model too. Batch tests proved as a useful tool for sludge characterization and model validation. The standard Dutch procedure for in¯uent and sludge characterization proved satisfactory for the model construction. Modeling of alternative BPR process con®guration showed that good P removal was achieved by all three alternative process con®gurations, by the latest one with comparatively lowest construction and operational costs (lower building costs and no acetate addition). Valuable experience from practical application of the model was obtained; study indicated where the model should be improved; the plant operation and treatment processes were better understood and plant performance was further optimized. # 2000 Elsevier Science Ltd. All rights reserved Key wordsÐactivated sludge, biological phosphorus removal, modeling, characterization, calibration, validation, batch test, full-scale wastewater treatment plant INTRODUCTION Biological phosphorus removal (BPR) is a complex process if compared to N and COD removal. Many dierent interferences with the other processes might occur. Mathematical simulations of full-scale BPR processes can help quantitatively evaluating these interactions. Several dierent models, such as activated sludge model no.1: ASM no.1 (Henze et al., 1987), ASM No. 2 (Henze et al., 1994), ASM No. 2d (Henze et al., 1999), ASM no.3 (Gujer et al., 1999), `Delft bio-P Model' (Murnleitner et al., 1997; Van Veldhuizen et al., 1999) are suitable for application to full-scale wwtp. ASM No. 1 has been used for more than a decade as a tool for modeling the removal of organic matter and for nitri®cation and denitri®cation processes; considerable experi- ence with this model has been acquired. However, for ASM No. 2, the situation is dierent. It has not been validated extensively due to the fact that the model became available only recently. Simul- taneously to ASM No. 2, the Delft BPR model was introduced. This model was validated in enriched BPR laboratory systems over a range of SRT values (Smolders et al., 1995a), or dierent anaerobic/ aerobic times (Kuba et al., 1997) and oxygen or nitrate as electron acceptor (Murnleitner et al., 1997), as well as during both start-up and steady state conditions (Smolders et al., 1995b). Recently, this combined model was for the ®rst time applied on the full-scale wwtp Holten (BCFS 1 process) in the Netherlands (Van Veldhuizen et al., 1999). In this study, the model was used to check the per- formance of Phostrip 1 -like process at wwtp Wat. Res. Vol. 34, No. 3, pp. 846±858, 2000 # 2000 Elsevier Science Ltd. All rights reserved Printed in Great Britain 0043-1354/00/$ - see front matter 846 www.elsevier.com/locate/watres PII: S0043-1354(99)00219-5 *Present address: IWACO B.V. Consultants for Water and Environment, Postbus 8520, 3009 AM Rotterdam, the Netherlands. {Author to whom all correspondence should be addressed. Tel.: +31-10-2865-483; fax: +31-10-4209-084; e-mail: d.brdjanovic@rtd.iwaco.nl