Insight into the effect of in-situ galvanic micro-coagulation on membrane fouling mitigation treating surface water

Membrane fouling is an inevitable drawback of the membrane based long-term operations. In this study, we investigated a spontaneous galvanic process for membrane fouling mitigation, which termed as the in-situ galvanic micro-coagulation (GMC) process. Results demonstrated that the GMC contributed to a lower transmembrane pressure development in contrast with the control system (7.15 vs 14.11 KPa/LMH/cP for about 1200 h operation). Significantly, a reduced concentration of extracellular polymeric substances (EPS) in terms of polysaccharides and proteins was observed for the GMC system on both the membrane surface and membrane pores, in comparison with the control system i.e. (134.09 ± 7.37 vs 379.55 ± 9.64 μg/cm 2 of polysaccharides and 27.48 ± 2.48 vs 35.87 ± 3.53 μg/cm 2 of proteins) and (70.46 ± 1.93 vs 120.46 ± 3.21 μg/cm 2 of polysaccharides and 17.96 ± 1.39 vs 20.52 ± 2.12 μg/cm 2 of proteins) respectively. Additionally, higher accumulation of EPS on the membrane surface of control system results in higher roughness of biofilm, lower porosity, robust and thicker biopolymer microstructure as compared to the GMC system. This kind of morphology and biofilm structure formed on the membrane surface of control system directly contributed to the higher transmembrane pressure. Overall, this work shows a potentially feasible and promising approach for membrane fouling mitigation, especially for the decentralized system with relatively low permeate flux .