Optimization of ammonia and COD removal from municipal wastewater effluent by electrochemical continuous flow reactor equipped with Ti/RuO2 and Cu foam

• Published in: Journal of water process engineering Vol. 55; p. 104185
• Main Authors: Mardani, Shima, Baghdadi, Majid, Torabian, Ali, Goharrizi, Behnoush Aminzadeh
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-10-2023
• Subjects: Active chlorine; Ammonia nitrogen; Box-Behnken design; Copper foam; Electrochemical oxidation; Active chlorine; Copper foam; Box-Behnken design; Ammonia nitrogen; Electrochemical oxidation
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2023.104185

The aim of the present work was to study an electrochemical continuous-flow reactor for the removal of ammonia nitrogen (NH4+N), its by-product, and Chemical Oxygen Demand (COD) from synthetic and real municipal wastewater effluent. In this study, Ti/RuO2 electrode was prepared by the thermal decomposition method for the removal of NH4-N and COD. Characterization of the Ti/RuO2 was accomplished using FE-SEM, EDS, AFM, and XRD. Cyclic voltammetry and Tafel curves were used for the electrochemical feature of the Ti/RuO2 electrode. Box-Behnken Design (BBD) method was used to optimize the operating conditions. The effects of four independent parameters including the initial concentration of NH4+ (10–30 mg/L as N), Cl− concentration (100–500 mg/L), HRT (30–100 min), and current (0.4–1.4 A) were examined using continuous experiments for the removal of NH4+N and COD. Characterization results confirmed that RuO2 was successfully coated on the surface of titanium mesh. Optimum conditions for Cl− concentration, HRT, and current were 490 mg/L, 100 min, and 1.36 A, respectively for an effluent concentration of 30 mg/L NH4+N and 30 mg/L of COD. Under these conditions, the removal efficiencies of NH4+N and COD were respectively 97.79 and 89.64 %, and the concentration of NO3−N was 1.93 mg/L. This work highlights the importance of an electrochemical continuous flow reactor for further removal of nitrogen and COD from the effluent of municipal wastewater treatment plants.
•Effluent of municipal wastewater was treated by continuous electrochemical system.•Copper foam was used as the cathode and Ti/RuO2 mesh was used as the anode.•The designed system was used for the removal of NH4+and COD from real wastewater.•The performance of the continuous system was higher than that of batch reactor.•98.4 % of NH4+N and 91 % of COD were removed using current density of 6.8 mA/cm2.