Impact of biological constituents and properties of activated sludge on membrane fouling in a novel submerged membrane bioreactor

A 12-l submerged membrane bioreactor was developed to remove carbon and nitrogen simultaneously using synthetic wastewater. In this study, the main objective was to investigate the impact of activated sludge properties on membrane fouling in the novel submerged MBR. The activated sludge properties were characterized by biological constituents (mixed liquor suspended solids (MLSS), extracellular polymeric substances (EPS) and soluble microbial products (SMPs)), morphological parameters (filament index (FI), volume equivalent diameter (D (4,3)) and fractal dimension (Df)) and rheological properties (apparent viscosity (ηa)). The influences of activated sludge properties on membrane fouling were quantified using statistical methods. The results showed that Df and EPS have strong and moderate positive effects on the membrane fouling resistance respectively, while MLSS was inversely correlated to the membrane fouling resistance. This study indicated that Df, EPS and MLSS were the predominant factors affecting the membrane fouling resistance.