Ozone assisted alternating current-electrocoagulation technique for color and COD removal with determination of electrical energy from industrial wastewater

Abstract

The use of conventional direct current-electrocoagulation (DC-EC) in wastewater treatment is limited by its drawbacks, which include electrode passivation, high energy consumption, and significant sludge production. Therefore, to address these issues, alternating current–electrocoagulation (AC-EC) has been developed. This research aimed to compare the efficacy of advanced oxidation processes (AOPs) and electrochemical including ozone (O3), DC-EC, AC-EC, and O3-direct/alternating current-electrocoagulation (O3-DC/AC-EC) processes, with regard to the elimination of color and chemical oxygen demand (COD) (%) from distillery industrial wastewater (DIW). Additionally, the study assessed the usage electrical energy (UEE) associated with each process. The results of the experiments indicate that the hybrid O3-AC-EC process achieved complete color–100% and COD–100% removal efficiencies while using less electrical energy—4.90 kWhr m−3—than single processes like O3, DC-EC, AC-EC, and hybrid O3-DC-EC. Using a hybrid O3–AC–EC method, the effects of important operational factors on COD removal efficiency (%) and UEE of DIW were examined. These parameters were COD, pH, treatment duration, distance between electrodes, concentration of O3, current density, electrode pairing, and pulse duty cycle. This work also investigated and reported on the synergistic effect of the O3 and AC-EC processes, as well as kinetic investigations of the O3-AC-EC technique. The O3-AC-EC approach efficiently and effectively removes contaminants from wastewater, making it the most suitable process when compared to the others.