Insights into quorum quenching mechanisms to control membrane biofouling under changing organic loading rates. (September 2017)

• Record Type: Journal Article
• Authors: Waheed, Hira; Xiao, Yeyuan; Hashmi, Imran; Stuckey, David; Zhou, Yan
• Is Part Of: Chemosphere. Volume 182(2017)
• Page Start: 40
• Page End: 47
• Publication Date: 2017-09
• Subjects: Membrane bioreactor (MBR) -- Biofouling -- Quorum sensing -- Quorum quenching -- Organic loading rate (OLR); Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2017.04.151
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: A quorum quenching (QQ) consortium comprised of both acyl homoserine lactones (AHLs)- and autoinducer-2 (AI-2)-degrading bacteria, either immobilized in polymer-coated alginate beads or in liquid suspension, was examined for fouling control in lab-scale MBRs under both steady and changing organic loading rates (OLRs). Under steady conditions the QQ consortium retarded biofouling by a factor of 3. However, a continuous increase in OLR vastly reduced the effectiveness of QQ bacteria; the biofouling was retarded only by factors of 1.4–1.8. A significant increase in extracellular polymeric substance (EPS), especially loosely-bound EPS in mixed liquor together with an increase in polysaccharide content up to 4 times in EPS resulted from the increase in OLR, was attributed to the impaired QQ efficacy. In control MBRs, cake layer resistance was the major factor (>60%) contributing to the increased trans-membrane pressure, as compared with pore blockage resistance and intrinsic membrane resistance. In contrast, the pore blockage resistance became dominant in QQ MBRs (>40%). Graphical abstract: Highlights: Impact of OLR on QQ based biofouling control was investigated. An increase in OLR resulted in higher EPS levels in the biocake and bulk sludge. S-EPS and LB-EPS were the major contributors to membrane fouling. Within EPS, polysaccharides contributed more to membrane fouling than proteins. Transient conditions reduced the efficacy of immobilized QQ bacteria.