Membrane fouling – a review on the role of EPS

The role of EPS is not clear to date. A literature review suggests that its importance is greater at lower SRTs and during unsteady operation. Fluctuating levels of dissolved oxygen and nitrate appear to have a profound impact on EPS uptake rate and thereby on EPS concentration. However, higher dissolved EPS concentration do not necessarily yield increased fouling. The general applicability of results is hampered by the fact that experimental and analytical procedures as well as terminology differ strongly [7,13,18]. In addition to more detailed and preferably standardised analytical methods, an integrated approach taking into account all and possibly interdependent parameters is required in order to obtain universally valid correlations for prediction of EPS levels and their fouling propensity. It is worth noting that the amount of EPS and also the spatial distribution of EPS inside the biofilm may affect membrane filterability.