Abstract:Membrane fouling is an unavoidable and challenging issue in the engineering application of membrane bioreactors (MBRs), significantly limiting the economic and environmental benefits of this technology. The fouling formation processes in MBRs involve a range of physical, chemical, and biological mechanisms. They are influenced by multifaceted factors such as membrane properties, mixed liquor characteristics, operating parameters, and influent quality. A major contributor to MBR fouling is biofilm formation, primarily driven by microbial coordinate behaviors. Due to the key role of quorum sensing (QS) in regulating biofilm formation, quorum quenching (QQ), a strategy that disrupts normal QS pathways, offers a novel approach to inhibit biofouling at its source. The implementation of QQ-based control involves the selection of highly active QQ compounds, enzymes, and bacteria. These agents are applied through various immobilization techniques, such as incorporation into sodium alginate, polymer composites, and silica or chemical modification of the membrane material surface. These approaches have demonstrated significant success in delaying fouling processes in lab-scale MBRs, which could extend the membrane fouling cycle by up to 10 times and maintain QQ activity for over 160 d. Additionally, QQ strategies can alter the relative abundance of bacterial taxa associated with fouling formation, community diversity, and interspecies interaction patterns, thereby leading to the shift of microbial community structures within MBRs. To promote the practical application of QQ strategies, future work should focus on accurately identifying the role of QS in membrane fouling under complex conditions, understanding the microecological responses to QQ, and developing high-performance QQ immobilization media that can withstand various adverse factors.
