Effect of Micro-Granular Activated Carbon on Bacteriophage Ms2 Removal and Fouling Control in Flat-Plate Mbr

Abstract

The pathogenic microorganisms pose a severe risk to the aquatic environment and human health. Membrane bioreactors (MBRs) have attracted much attention due to their simultaneous biological treatment and virus retention, but membrane fouling is the main obstacle. This study explored the effect of micro-granular activated carbon (μGAC) on bacteriophage MS2 removal efficiency and membrane fouling in a flat-plate MBR. The results showed that the μGAC addition with a particle size of 180-300 μm improved the removal of MS2 with LRVMBR of 4.77 log, as well as the COD and ammonia nitrogen removal. The μGAC integrated MBR (μGAC-MBR) exhibited a higher MS2 retention rate by the membrane filter layers with an average LVRMem of 2.03 log in compared to that of a control reactor (C-MBR) of 1.89 log. Meanwhile, the total membrane filter layer resistance of μGAC-MBR was obviously lower than C-MBR. The μGAC slightly decreased MS2 adsorption by activated sludge, while it significantly altered extracellular polymeric substances (EPS) profiles, reducing fluorescent components in the bound EPS and decreasing the PN/PS ratio of the activated sludge. The atomic force microscope (AFM) and contact angle analysis of the surface filer layer indicated that μGAC enhanced membrane surface roughness and hydrophilicity. Notably, the μGAC significantly influences the quorum sensing (QS) systems, reducing the abundance of AHL-related genes and their synthesis. The synthase luxI in the AHL-QS system was reduced by 93.21% in μGAC-MBR. The AHL-QS system is closely related to biofilm formation, and the total EPS of the surface filer layer of μGAC-MBR decreased by 57.73%, and PN in LB-EPS and TB-EPS decreased by 91.33% and 54.44% compared with C-MBR, indicating a significant reduction in biofilm formation. This study exhibits a new perspective on promoting MS2 removal with the synergistic effect of alleviating fouling in the MBR process.

Keywords: membrane bioreactor, Micro-granular activated carbon, Bacteriophage MS2, membrane fouling, Quorum sensing