In tandem effects of activated carbon and quorum quenching on fouling control and simultaneous removal of pharmaceutical compounds in membrane bioreactors

Abstract

This study aimed to integrate the quorum quenching (QQ) strategy with powdered activated carbon (PAC) adsorption for fouling control and simultaneous removal of trace amounts of selected pharmaceutically active compounds (PhACs) in laboratory membrane bioreactors (MBRs). With the addition of QQ strains immobilized in PAC-alginate beads, a 4.6-folds delay in fouling was achieved. The QQ strains not only altered the sludge properties, but also influenced the microbial communities in the MBRs, thus leading to distinct quorum sensing signal molecule (acyl-homoserine lactones, AHLs) profiles. Despite the difference in AHL profiles, the total AHL concentrations were greatly reduced in bulk sludge, and completely quenched in biocake with QQ supplementation. PAC addition enabled high removals of all PhACs, and also resulted in a prominent increase in sludge floc size, which further enhanced sludge filterability. These QQ-entrapped PAC-alginate beads provide a novel MBR setting with less biofouling and high removal efficiency of PhACs.