Reshaping the Activated Sludge Model ASM2d for Better Manageability and Higher Integration Potential

The European Water Framework Directive has pointed out that the best model for water management is management by river basin. However, to obtain an overview of the water quality in a river basin system, one has to look at the individual components of the system such as the sewer network, the wastewater treatment plant and the receiving water bodies and the interaction between them. Within this study, we develop an adjusted model from the original state-of-the-art activated sludge ASM2d model with as main focus to maximize the compatibility with the sewage and river water quality models while still assuring a sufficient prediction capacity of the activated sludge system. To this end, and to avoid the commonly required fractionation into the classic activated sludge model state variables, the latter are directly derived from the outputs of the sewage model (e.g., BOD5, COD, TN or TP) for the adjusted model. Furthermore, the modified ASM2d model is made more realistic and can be more broadly applied due to the re-introduction of organic nitrogen and phosphorus component state variables. While developed on the basis of the data of a wastewater treatment plant in Belgium, the validation of the adjusted model on a data set of a wastewater treatment plant in Girona (Spain) is highly promising.