Electrochemical treatment of solid waste Leachate using combined electrocoagulation and electrochemical oxidation treatment

Abstract

The combined electrocoagulation and electrochemical oxidation (EC-EO) technique was used to electrochemically treat solid waste leachate by efficiently removing COD, nitrogen-based products, and chromium using bipolar and monopolar electrodes arranged in one reactor with BDD as an anode, stainless steel as a cathode, and Al as bipolar electrode. After 12 hours of treatment, the removal efficiency of the EC-EO reactor was 22% higher than that of the EO reactor, and after 24 hours of treatment, the COD removal efficiency of the EC-EO and EO reactors was 98.5% and 97.8%, respectively. After 24 hours of EC-EO treatment at 0.7 A current intensity, NH4+-N, Cr (VI), and TN removal efficiency was 85.8%, 85.3%, and 62.2% for NH4+-N, Cr (VI), and TN, respectively. The integration of EO with the EC process enhanced overall performance, as indicated by the results in terms of energy usage. The EC-EO procedure uses 50kWh/kg to remove 98% of COD and 847kWh/kg to remove 85% of NH4+-N, respectively. The combined EC-EO method removed more than 97%, 63%, 62%, and 40% of COD, NH4+-N, Cr (VI), and TN from solution after 16 hours. The pH effect in the study also revealed that neutral or acidic conditions are beneficial for great treatment during the EC-EO process, and removal efficiencies are increased by decreasing the initial pH value to 4 and 6.5, and more than 90% treatment of COD, NH4+-N, Cr (VI), and TN was obtained in less than 16 hours in the combined EC-EO process, and pH=6.5 was chosen as the optimal pH value for the combined EC-EO process. A comparison of the developed treatment method with other reported reactors in the literature revealed that the developed reactor performed similarly to some reported reactors, if not better, which can be attributed to the well-organized and efficient activity of electrodes in the presented EC-EO reactor.