Comparison of ozonation, Fenton, and photo-Fenton processes for the treatment of textile dye-bath effluents integrated with electrocoagulation

Abstract

This study aims to investigate treatment efficiency and evaluate the energy efficacy of integrated electrocoagulation system combined with ozonation, Fenton, and photo-Fenton processes for successful textile dye-bath effluents' treatment. In this regard, the characterization of physicochemical parameters such as pH, turbidity, salinity, total dissolved solids (TDS), total suspended solids (TSS), electrical conductivity (EC), and chemical oxygen demand (COD) was analyzed to estimate removal efficiency of each treatment process. Moreover, the electrical energy consumption of all aforementioned processes was measured individually to work out cost-effectiveness. Fenton process appeared to be ineffective for reducing COD and other parameters. While the overall performance of ECS alone showed far better results, COD and color removal efficiencies were 57.4%, and 40%, respectively. However, the application of ECS/O3 resulted in complete decolorization and almost 99.7% COD removal under optimized operating conditions including ozone flow 300 mg/h, pH 7.1, Temperature 25 °C. ECS/photo-Fenton process resulted in COD, and color removal of 95.6%, and 97%, respectively. Electrical Energy per Order of ECS was found 1.58 kWh/m3 for minimum removal of dyes and COD. ECS/Ozonation is responsible for 100% decolorization but at a very high cost. ECS/photo-Fenton process proved to be the second-best option in terms of treatment and energy consumption. Hence, an integrated treatment system of ECS with AOPs appeared to be the most feasible and eco-friendly. That could lead to the treated wastewater for reuse and recycling purposes within the industry.