Determination of the optimal electrocoagulation operational conditions for pollutant removal and filterability improvement during the treatment of municipal wastewater

This study aims to determine optimal electrocoagulation (EC) operational conditions for removal of nutrients and organic matter and improving the mixed liquor filterability during municipal wastewater treatment in a Submerged Membrane Electro-Bioreactor (SMEBR). First, the optimal electric-current exposure time for the removal of PO 4 -3 -P, NH 4 + -N, and chemical oxygen demand (COD) was determined. Then, different EC conditions were tested by varying the current density, mode of exposure, and pH, using a factorial design. Finally, the impact of the optimal conditions on biomass activity was evaluated. The observed optimal operational conditions were a current density of 10 Am -2 with an exposure mode of 6'ON/30'OFF at pH 8. Using these optimal conditions, electrocoagulation achieved high removal efficiencies of 99.51%, 98.56%, and 99.04% for PO 4 -3 -P, NH 4 + -N, and COD, respectively, after 48 hours of treatment. An increase in the size of the flocs, under these optimal conditions, improved filterability to 98.76%, which reduces membrane fouling in an SMEBR. In addition, the optimized conditions increased the autotrophic and heterotrophic oxygen uptake rate, demonstrating that EC can be applied in an SMEBR without reducing the biomass activity.