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

• Published in: Journal of water process engineering 2020-08, Vol.36, p.101295, Article 101295
• Main Authors: Follmann, Hioná Valéria Dal Magro, Souza, Emerson, Aguiar Battistelli, André, Rubens Lapolli, Flávio, Lobo-Recio, María Ángeles
• Format: Article
• Language: English
• Subjects: Biomass activity; Electrocoagulation; Factorial design; Mixed liquor filterability; Nutrient removal
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2020.101295

[Display omitted] •Electrocoagulation used to treat sewage in Submerged Membrane Electro-Bioreactors.•Lower currents with lower exposure times improved the removal of pollutants.•Higher currents with high exposure times improved the filterability of wastewater.•Optimal conditions: 10 Am-2, 6'ON/30'OFF, pH 8 (using a factorial design).•Electrocoagulation stimulated the activity of the microorganisms. 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 PO4-3-P, NH4+-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 PO4-3-P, NH4+-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.