Effect of electrocoagulation on MBR under different power supply conditions

Abstract

The impact of electrocoagulation (EC) on membrane bioreactor (MBR) under different power supply conditions was investigated in this study, which included constant voltage/current of 1 V, 3 V, 5 V and 0.15 A from direct current (DC) power source and undulate voltage from 18 V/10 W solar panel. The EC actuated by constant current of 0.15 A from DC power source and undulate voltage from 18 V/10 W solar panel could mitigate the membrane fouling obviously with 14 and 20 days of operation times, respectively, as results of sludge bulking inhibition and specific resistance to filtration (SRF) reduction after effective EC. When the EC was applied, the suitable power supply condition could inhibit the sludge bulking caused by filamentous bacteria well. The protein and polysaccharide reduced from SMP and LB-EPS of sludge and filter cake was another reason for membrane fouling mitigation. The application of EC in MBR could also improve the removal efficiency of pollutants, especially for phosphate (PO43−). The maximum removal efficiency of PO43− was 92.45% under 5 V condition with influent PO43− of 26.20 ± 0.11 mg/L. The community diversity could be maintained well although community richness was reduced in EC-MBR during operation. The EC could embed the filamentous bacteria inside sludge particle and then eliminate its effect on membrane fouling.