Modelling and simulation of filtration performance in membrane bioreactor systems for municipal wastewater treatment

The paper outlines a model of the filtration performance of submerged capillary microfiltration modules in membrane bioreactor applications for wastewater treatment. The model was implemented for process simulation and calibrated by using operating data of the full-scale municipal wastewater treatment plant Rödingen, Germany, operated by Erft River Association (Erftverband), which is equipped with activated sludge treatment and microfiltration units for biomass retention. Mathematically recordable foundations of filtration resistances, such as cake layer forming and fouling, are presented along with a mass transfer model, describing the concentration polarisation on the feed-side and its dependence on a multiphase flow regime. The model simulates the long-term decrease in permeability of the membranes and outlines the influence of main operating parameters on flux performance. After parameter fitting for one filtration unit, the permeability evolution for a second unit could be also calculated.