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

• Published in: Journal of membrane science 2020-09, Vol.610, p.118234, Article 118234
• Main Authors: Xu, Lei, Wei, Chaocheng, Siddique, Muhammad Saboor, Yu, Wenzheng
• Format: Article
• Language: English
• Subjects: Biofilm microstructure; Biopolymers; Galvanic micro-coagulation; Membrane fouling; Ultrafiltration
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2020.118234

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/cm2 of polysaccharides and 27.48 ± 2.48 vs 35.87 ± 3.53 μg/cm2 of proteins) and (70.46 ± 1.93 vs 120.46 ± 3.21 μg/cm2 of polysaccharides and 17.96 ± 1.39 vs 20.52 ± 2.12 μg/cm2 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. [Display omitted] •The in-situ GMC is utilized to alleviate UF membrane fouling for the first time.•GMC can effectively reduce the biopolymers in surface water.•The accumulation of EPS on membrane surface is inhibited by GMC.•GMC leads to a higher porosity biofilm with thinner and slender microstructure.•GMC weakens the interactions between the biofilm and the membrane surface.