Fouling mitigation by TiO₂ composite membrane in membrane bioreactors

Membrane bioreactors (MBRs) have attracted widespread attention in advanced water treatment because of their production of consistent and high-quality effluent. However, membrane fouling during operation has greatly hindered their application. Studies have suggested that a coating of TiO2 nanoparticles on membranes may reduce membrane fouling by enhancing the hydrophilicity of the membrane. In this study, two membranes were coated with TiO2 nanoparticles for membrane fouling mitigation. To evaluate the filtration performance of the TiO2 composite membranes, a synthetic wastewater was prepared to model the municipal wastewater for the MBR operation. The mixed liquor from the MBR was used in the filtration test to evaluate the performance of the TiO2 composite membrane. Filtration tests showed that membrane fouling was reduced substantially, which was attributable to the increased hydrophilicity of the membrane. Results also shows that optimal amount of coating is important in fouling mitigation. An ultrasonic washing test suggests that most of the TiO2 particles were firmly coated on the surface of the composite membrane.