<p>In this study, the treatability of a chemical industry wastewater by coagulation-flocculation pretreatment followed by persulfate oxidation process was investigated. In pretreatment, iron chloride (FeCl₃), aluminum sulfate (Al₂(SO₄)₃) and polyaluminum chloride (PAC) coagulants were tested at different pH and dose conditions, and the best COD and TOC removal efficiency was obtained with FeCl₃ at pH 7 and 1750&#xa0;mg/L dose. After coagulation-flocculation, UV (UVA, UVB, UVC) and heat (50–90&#xa0;°C) activated persulfate oxidation processes were applied to the wastewater and their performances were compared. The highest removal efficiency in UV activation was achieved with UVC, and a total of 89.8% COD and 84.6% TOC removal was obtained. In heat activation, as the temperature increased, the removal efficiency increased, and 91.9% and 95.8% COD and 86.1% and 91.6% TOC removal was achieved at 70&#xa0;°C and 90&#xa0;°C, respectively. However, the increase in removal was limited after 70&#xa0;°C and the cost increased significantly. According to the cost analysis, oxidation studies conducted at 70&#xa0;°C were determined to be the most suitable option in terms of removal efficiency and cost. As a result, it was revealed that chemical industry wastewater can be effectively treated with UV or heat-activated persulfate oxidation processes after coagulation-flocculation pretreatment.</p>