Application of response surface methodology for investigation of membrane fouling behaviours in microalgal membrane bioreactor: the effect of aeration rate and biomass concentration

Abstract

This study was performed to investigate membrane fouling phenomena and to optimize fouling parameters in a submerged membrane bioreactor. An ideal experimental design was carried out based on central composite design (CCD) with response surface methodology (RSM). This RSM was used to calculate the effects of microalgae concentration, aeration rate and their interaction with membrane fouling and permeate flux. Based on the analysis of variance (ANOVA), the permeate flux model proved to be of very good fit with a very low probability value (<0.0001). High permeate flux occurred at low microalgae concentrations and optimum aeration rate (2.5 L min⁻¹). Minimum total resistance was 2.65 × 10⁻¹¹ m⁻¹ at optimum aeration rate and microalgae concentration of 0.65 g L⁻¹. Furthermore, a high microalgae concentration released larger amounts of extra-cellular polysaccharides (EPS), resulting in severe fouling.