Activated sludge pilot plant: Comparison between experimental and predicted concentration profiles using three different modelling approaches

This paper presents an experimental and numerical study of an activated sludge channel pilot plant. Concentration profiles of oxygen, COD, NO3 and NH4 have been measured for several operating conditions. These profiles have been compared to the simulated ones with three different modelling approaches, namely a systemic approach, CFD and compartmental modelling. For these three approaches, the kinetics model was the ASM-1 model (Henze et al., 2001). The three approaches allowed a reasonable simulation of all the concentration profiles except for ammonium for which the simulations results were far from the experimental ones. The analysis of the results showed that the role of the kinetics model is of primary importance for the prediction of activated sludge reactors performance. The fact that existing kinetics parameters in the literature have been determined by parametric optimisation using a systemic model limits the reliability of the prediction of local concentrations and of the local design of activated sludge reactors.

► This study is one of the first papers comparing experimental concentration profiles inside a activated sludge reactor to the results of three different models (CFD, compartmental, systemic).
► It is one of the first times that the compartmental approach has been validated in the case of real biological reactions.
► It was shown that the kinetics model has a strong influence on the concentration profiles predictions.