AN INTEGRATED METABOLIC MODEL FOR THE AEROBIC AND DENITRIFYING BIOLOGICAL PHOSPHORUS REMOVAL

In this work, an integrated metabolic model for biological phosphorus removal is presented. Using a previously proposed mathematical model i t was shown to be possible to describe the two known biological phosph orus removal processes, under aerobic and denitrifying conditions, wit h the same biochemical reactions, where only the difference in electro n acceptor (oxygen and nitrate) is taken into account. Though, apart f rom the ATP/NADH ratio, the stoichiometry in those models is identical , different kinetic parameters were found. Therefore, a new kinetic st ructure is proposed that adequately describes phosphorus removal under denitrifying and aerobic conditions with the same kinetic equations a nd parameters. The ATP/NADH ratio (delta) is the only model parameter that is different for aerobic and denitrifying growth. With the new mo del, simulations of anaerobic/aerobic and anaerobic/denitrifying seque ncing batch reactors (A(2) SBR and A/O SBR) were made for verification of the model. Not only short-term behavior, but also steady state, wa s simulated. The results showed very good agreement between model pred ictions and experimental results for a wide range of dynamic condition s and sludge retention times. Sensitivity analysis shows the influence of the model parameters and the feed substrate concentrations on both systems. (C) 1997 John Wiley & Sons, Inc.