Effect of quorum quenching on the reactor performance, biofouling and biomass characteristics in membrane bioreactors

Enzymatic quorum quenching has recently been shown to be a promising approach to mitigate biofouling in membrane filtration processes. However, its universal effectiveness and mechanisms need further research. In this study, acylase was immobilized into sodium alginate capsules for enzymatic quorum quenching in MBRs operated at typical sludge concentrations (MLSS ≈ 10 g/L) for extended period of time. The results showed that quorum quenching influenced sludge characteristics and biofouling, while not impacting pollutant degradation. Better sludge settleability, smaller sludge particle size, less SMP and EPS production, lower apparent viscosity and higher zeta potential of mixed liquor were observed with quorum quenching. Quorum quenching also influenced the characteristics, behavior and function of SMP and EPS, which weakened biofilm formation ability but enhanced membrane filterability.

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► How does quorum quenching affect the broth characteristics in MBR was discussed.
► MBR performance, biomass characteristics and biofouling were monitored.
► Characteristics, behavior and function of SMP/EPS in liquid and biocake were studied.
► What will happen if quorum quenching ceases were also investigated.
► Our work helps to understand origination and mitigation mechanism of biofouling.