Comparison of kinetics and costs of Fenton and photo-Fenton processes used for the treatment of a textile industry wastewater

In this study, the treatment of textile industrial wastewater by Fenton and Photo-Fenton oxidation processes was investigated. For this purpose, the pH, Fe2+ and H2O2 concentrations with the best organic matter and color removal were determined in the Fenton process and comparison with Fenton was made by Photo-Fenton oxidation at the optimal Fe2+/H2O2 ratio. The influent COD and TOC values of the wastewater used in the study were 848 mg/L and 253 mg/L, respectively. With the Fenton process, the best organic matter and color removal was obtained at pH 3, at 200 mg/L Fe2+ and 300 mg/L H2O2 concentrations. Under these conditions, 88.9% COD, 84.2% TOC and over 97% color removal were obtained with Fenton oxidation, and 93.2% COD, 88.9% TOC and 98% color were obtained with Photo-Fenton oxidation. However, when Fe2+ and H2O2 amounts were reduced to 50 mg/L and 75 mg/L, both organic matter and color removal were reduced with Fenton process, while higher organic matter removal and color removal were achieved with Photo-Fenton process. The total cost was changed between 9.56-16.88 euro/m3 and 13.46-20.13 euro/m3 with Fenton and Photo-Fenton oxidation process for all Fe2+/H2O2 ratios, respectively. With the Photo-Fenton oxidation process, higher organic matter removal was obtained at optimum Fe2+ and H2O2 concentrations. In addition, less Fe2+ and H2O2 chemicals were used in Photo-Fenton oxidation process to achieve the same removal efficiency compared to the Fenton oxidation process.