Novel electrokinetic approach reduces membrane fouling Sharif Ibeid a, *, Maria Elektorowicz a , Jan A. Oleszkiewicz b a Dept. of Building, Civil and Environmental Eng., Concordia University, Montreal, Canada H3G 1M8 b Dept. of Civil Engineering, University of Manitoba, Winnipeg, Canada R3V 1T9 article info Article history: Received 14 April 2013 Received in revised form 4 July 2013 Accepted 6 August 2013 Available online 22 August 2013 Keywords: Submerged membrane electro- bioreactor (SMEBR) Membrane bioreactor (MBR) Extra-polymer substances (EPS) Membrane fouling Electrokinetics Soluble microbial products (SMP) Floc-bound water abstract An innovative submerged membrane electro-bioreactor (SMEBR) was built to reduce membrane fouling through a combination of various electrokinetic processes. The objec- tive of this research was to assess the capability of SMEBR to reduce fouling under different process conditions. At the bench scale level, using synthetic wastewater, membrane fouling of the SMEBR was compared to the fouling of a membrane bioreactor (MBR) in five runs. Different protein concentrations in the influent synthetic wastewater were selected to develop different membrane fouling potentials: high (240 mg/l), low (80 mg/l) and zero protein addition. The MBR and SMEBR were operated at a flux equal to the membrane critical flux in order to create high fouling rate conditions. Membrane fouling rate, expressed as the change in the trans-membrane pressure per day (kPa/d), decreased in the SMEBR 5.8 times (standard deviation (SD) ¼ 2.4) for high protein wastewater, 5.1 times (SD ¼ 2.4) for low protein content, and 1.3 times (SD ¼ 0.7) for zero protein, when compared to the MBR. The supernatant concentrations of the soluble microbial products (SMP) were 195e210, 65e135 and less than 65 mg/l in respective experimental series. Following the bench scale study, membrane fouling was assessed in a pilot scale SMEBR, fed with raw un- clarified municipal wastewater, and operated under real-sewage variable quality condi- tions. The pilot SMEBR exhibited three times smaller membrane fouling rate than the MBR. It was concluded that electrokinetic processes generated by SMEBR led to a reduction of membrane fouling through: i) removal of soluble microbial products (mainly protein and polysaccharides) and colloidal organic materials; ii) change of the structure and morphology of the suspended solids due their conditioning by DC field. ª 2013 Elsevier Ltd. All rights reserved. 1. Introduction In spite of the growing applications of submerged membrane bioreactors (MBRs), the reduction of flux over time caused by membrane fouling remains the major issue to be resolved to ensure the sustainability of this technology (Drews, 2010; Meng et al., 2009; Le-Clech et al., 2006; Chang et al., 2002). Fouling has been typically classified as reversible (recoverable by physical methods) and irreversible (recoverable by chemi- cal cleaning). This classification is not entirely useful as membrane permeability deteriorates over time, even when the best management practices are implemented. Meng et al. (2009) classified fouling as removable through physical cleaning, irremovable or removable only through chemical cleaning and irreversible fouling that cannot be removed by any means. Even more precisely, Drews (2010) classified * Corresponding author. Tel.: þ1 514 803 2216. E-mail addresses: s_ibeid@encs.concordia.ca, shareefobaid@hotmail.com (S. Ibeid). Available online at www.sciencedirect.com journal homepage: www.elsevier.com/locate/watres water research 47 (2013) 6358 e6366 0043-1354/$ e see front matter ª 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.watres.2013.08.007