Quorum sensing control and wastewater treatment in quorum quenching/ submerged membrane electro-bioreactor (SMEBR(QQ)) hybrid system

Membrane biofouling, in terms of quorum sensing (QS), reduction with hollow cylindrical quorum quenching (QQ) beads in submerged membrane bioreactor (SMBR(QQ)) and submerged membrane electro-bioreactor (SMEBR(QQ)) was investigated. Results showed that the rate of pressure increase (i.e. dTMP dt⁻¹) was 0.7 and 0.5 kPa d⁻¹ in SMBR(QQ) and SMEBR(QQ), respectively. Furthermore, sludge physicochemical and biological characteristics were analyzed in terms of mixed liquor suspended solids (MLSS), sludge volume index (SVI), time to filter (TTF), and mean sludge particle size (PSD). Results showed that the presence of electric field reduced SVI and TTF in the SMEBR(QQ) by 47 and 26%, respectively. Also, the concentration profiles of loosely bound extracellular polymeric substances (LB-EPS) and tightly bound EPS (TB-EPS) showed superiority in the performance of SMEBR(QQ) over SMBR(QQ). Chemical oxygen demand (COD) and nutrient removals were higher in the SMEBR(QQ) reporting 97, 90 and 90% removal of COD, ammonium-N (NH₄⁺-N) and phosphorus-P (PO₄^3--P), respectively. The synergetic effects of QQ and electric field have shown significant improvements of conventional MBRs and could be further developed as an efficient wastewater treatment and water reuse.