Feasibility of Implementing Qq Technology to Mitigate Membrane Fouling in Mbrs Treating Phenol-Rich Pharmaceutical Wastewater:  Application of Rohodococcus Sp. Bh4 and Qq Consortium

This study was the first to investigate the feasibility of implementing quorum quenching (QQ) technology to mitigate membrane fouling in a membrane bioreactor (MBR) treating phenol-rich pharmaceutical wastewater via using single QQ bacterium (Rohodococcus sp. BH4) and QQ consortium (QQcs). Herein, all three MBRs, including an MBR with dosage of Rohodococcus sp. BH4 (BH4-MBR), an MBR with dosage of QQcs (QQcs-MBR) and a control MBR (Co-MBR), exhibited chemical oxygen demand (COD), total organic carbon (TOC) and phenol removal efficiencies more than 94% and close to complete nitrification (99% NH4+-N removal efficiency). This indicated that the introduction of QQ to MBR did not have an adverse impact on treatment performance of MBRs. Besides, both Rohodococcus sp. BH4 and isolated QQcs could improve membrane filtration performance effectively, which could be attributed to the reduction of soluble microbial product (SMP) of activated sludge. Interestingly, the Rohodococcus sp. BH4 exhibited relative higher performance than QQcs. The TMP increase was delayed by 68.7% by Rohodococcus sp. BH4, while 31.3% was achieved by QQcs. This could be attributed to the relatively higher degradation for short- and medium-chain Acyl homoserine lactones (AHLs) by Rohodococcus sp. BH4 as compared with the QQcs. Besides, the possibly presence of quorum sensing (QS) bacteria within bacterial community composition of QQcs might contribute to the less efficiency of membrane fouling mitigation as compared to Rohodococcus sp. BH4.