Optimization of the Treatment of Chemical Industry Wastewater by Coagulation and Fenton Oxidation

ABSTRACT In this study, the treatment of chemical industry wastewater, which is used in producing auxiliary chemicals for various industries, through coagulation and Fenton oxidation was examined. Coagulation studies with alum were done at various pH levels and doses to find the best conditions for wastewater treatment, and the pre‐treated wastewater was treated with Fenton oxidation using different chemical oxygen demand (COD)/Fe 2+ and COD/H 2 O 2 ratios (by weight). During coagulation (pH 5, 300 mg/L alum), COD, total suspended solids (TSS), color index (CI), and turbidity removal efficiency was obtained as 74.8%, 92.0%, 93.0%, and 93.3%, respectively. After coagulation, Fenton oxidation was achieved at a COD/Fe 2+ /H 2 O 2 ratio of 1:3:7.5, resulting in 89.2% TSS removal, 97.3% turbidity removal, 97.7% CI removal, and 74.8% COD removal. As a result, the treatment of chemical industry wastewater through coagulation and Fenton oxidation processes resulted in TSS, turbidity, CI, and COD removal of 99.0%, 99.8%, 93.0%, and 93.5%, respectively. As chemical industry wastewater has high COD and TSS content and toxic properties due to various chemicals, it was thought that applying Fenton oxidation after pretreatment with coagulation process would reduce the chemicals used in Fenton oxidation and thus reduce the cost. In summary, it has been shown in this study that complex chemical industry wastewater containing various chemicals can be effectively treated by alum coagulation followed by Fenton oxidation.