Impact of electrocoagulation on membrane filtration resistance under different proportions of industrial wastewater: Impact of electrocoagulation on membrane filtration resistance

BACKGROUND: The principal purpose of the present work was to explore the mechanism of mitigation of membrane fouling in a periodic reversal submerged electro‐coagulation membrane bioreactor (SECMBR) with Fe–C electrodes. In this study, membrane resistance and activated sludge performance were compared in a SECMBR and a conventional submerged membrane bioreactor (SMBR). RESULTS: Adsorption fouling had a strong direct correlation with the soluble microbial products (SMP) and carbohydrates in SMP and had a moderate correlation with the mixed liquor volatile suspended solids, viscosity and average particle size. SECMBR enhanced the flocculation of suspended sludge, decreased the absolute value of the ζ potential, and maintained microbial activities. With increasing proportion of oil shale wastewater, more soluble microbial products were secreted by microorganisms in the SECMBR than in the SMBR. CONCLUSION: Electrocoagulation technology has the capacity to increase the sludge particle size and decrease the absolute value of the ζ potential to alleviate cake layer fouling and total resistance. As the proportion of oil shale wastewater was increased, microbial activity in the conventional MBR was inhibited, leading to less secreted SMP and a lower adsorption fouling rate. The results provide insight into understanding the mechanism of mitigation of membrane resistance in an SECMBR. © 2018 Society of Chemical Industry