Estimation of a Reduced Model of the BSM1 Activated Sludge Wastewater Treatment Plant

Abstract

The complete BSM1 model is recognized as representative of activated sludge plants. However, its large number of states may render it inadequate for development of state observers and for control. Thus, a reduced model has been developed for the two main sections of the plant, the anoxic and aerobic reactors. Concepts of model reduction of biological models based on the analysis developed by Bernard (Bernard2005a, Bernard2005b) have been used. The output data have been obtained by simulating the inlet by data representative of dry weather. After transformation and treatment of the data, it has been shown that a kinetic model reduced to two reactions is able to represent 80% of the total variance. The pseudo-stoichiometric coefficients have been estimated and the pseudo reaction scheme has been validated with respect to the actual concentrations at the outlet of a considered section. The dynamics are generally well represented by the reduced model.