Fouling characterization in aerobic granulation coupled baffled membrane separation unit

Aerobic granular sludge treatment system performs better than the conventional aerobic wastewater treatment in terms of treatability, strong microbial structure, high biomass retention and excellent settling ability. However, the effluent produced has high suspended solid content above the discharge standards. Thus, membrane filtration could be an alternative post-treatment process. This study was conducted to treat high strength wastewater using aerobic granulation reactor coupled with baffled membrane separation unit and to evaluate the fouling potential of the supernatant of the granulation reactor. The results showed that aerobic granulation reactor could operate at high organic loading of 15 kg COD/(m3 d) with crushed shell support media. Moreover, it was observed that the soluble polysaccharides (sPS) concentration in the supernatant of the granulation reactor (the most important fraction in soluble extracellular polymeric substances (sEPS) up to 84%) increased with an increasing organic load rate. The results suggest that irreversible adsorption of sEPS particularly sPS could be the main cause of membrane fouling.