The effect of electric field on membrane bioreactors performance and membrane fouling reduction

Rapid growth of population is leading to high water consumption and producing large amount of waste water which needs to be treated and being reutilized for reusing purposes.   Among sewage treatment methods, the use of integrated activated sludge and membrane separation is increasing due to advantages such as higher quality effluents, lower ecological footprint, less sludge production, and lower operational costs. Despite the many benefits, the problem of membrane fouling due to deposition and adsorption of colloidal and soluble material on the surface of membrane has limited the use of this method. There are several methods for eliminating and mitigating membrane fouling, each with disadvantages such as increasing costs, producing secondary pollutants, increasing sludge production, reducing the membrane life and durability, etc. In recent years, the use of electrical coagulation as a method to reduce membrane fouling in the MBR system has been taken into account. Submerged Membrane Electro Bioreactors (SMEBR) is a new approach that reduces clogging of the membrane by combining the MBR system with the electric field. In the forthcoming research, the effects of electric field on the system were investigated by applying a low voltage electric field (1.5 volts per cm) in the MBR reactor. The results of the experiments showed that applying the electric field in this case improves the characteristics of the wastewater (reducing the concentration of COD, nitrate and phosphate) and reducing the concentration of external polymeric substance (EPS) and soluble material product (SMP) protein. Also, the application of an electric field in MBR reactors reduces fouling and improves the output flux more than the conventional membrane.