Dynamic filtration – A novel approach for critical flux determination using different textiles

Abstract

Dynamic filtration which is characterized by high flux rates and low filter resistance is an attractive alternative to conventional microfiltration for membrane bioreactor (MBR) operation. Therefore the cake layer formation has been subject to intensive studies and modeling. In the case of dynamic MBRs (DMBRs) the understanding of the underlying principles of cake formation is of vital importance for further process optimization. The combination of purposely designed experimental set-ups and mathematical models are particularly useful to look into these complex processes. The main disadvantage using the constant pressure method is that stable situation occurs not straight away. Therefore an exact determination of filter resistance or critical flux is not possible. For the first time a modified set-up based on constant flux method to overcome the described problem is described for the first time. Outcomes, comparing the constant pressure and the new approach showed that the experimental design plays an essential role on cake formation in dynamic membrane systems as well as on the results which are obtained. The novel approach allows a better simulation of the critical flux model and is more suitable for the evaluation of the filtration behavior of mesh filters due to far better realistic simulation. Results gained concerning flux and trans-filter pressure behaviors in the large scale experiments could be verified in laboratory using this filtration set-up.This short communication is intended to be a thought-provoking impulse to discuss the mentioned implications and to offer suggestions for experimental approaches that allow improved insight into the cake formation process.