Effect of Suspended Carriers on Extracellular Polymeric Substances in MBR

Suspended carriers were added into a submerged membrane bioreactor (SMBR) using polypropylene non-woven fabric (PP NWF) as membrane model to treat synthetic wastewater. The changes of EPSSEPSB and EPS in activated sludge mixing liquid of MBR and in sludge on membrane model surface were researched at different aeration rate. The results showed that adding suspended carriers in MBR can increase the concentration of EPSS and EPSB in activated sludge mixing liquid, but the effect on EPSS and EPSB in the sludge on membrane model surface is related to aeration rate. Adding suspended carriers can increase the concentration of EPSS and EPSB in the sludge on membrane model surface at 0.10m3/h of aeration rate; the concentration of EPSS and EPSB in the sludge with suspended carriers is reduced when aeration rate is increased to 0.25m3/h. The study on the effect of aeration rate on EPS in sludge mixing liquid of MBR and in sludge on membrane model surface showed that an optimized aeration rate exists if suspended carriers are added to control MBR membrane fouling. At the optimized aeration rate, membrane fouling can be mitigated and controled effectively.