关键词: 混凝, 聚合氯化铝, 臭氧氧化, 羟基自由基, 焦化废水

Abstract: The process of coagulation-ozone oxidation for bio-treated coke plant effluents was studied, and the influence of poly-aluminum chloride (PAC) dosage, ozone concentration, pH value and reaction time on the removal of COD and chroma reduction was investigated. Based on both treatment cost and removal efficiency, optimum reaction conditions were proposed. Under the optimum conditions of a PAC dosage of 100 mg/L, an ozone concentration of 100 mg/L, a pH value of 10.61 and a reaction time of 30 min, the removal rate of COD and chroma reduction rate reached 80.05% and 96.74%, respectively. As compared with single ozone oxidation, the removal rate of COD and chroma reduction rate by coagulation-ozone oxidation increased 29.19 and 19.9 percentage points, respectively. The treated wastewater had a COD concentration of 53.87 mg/L and chroma reached 6 times, which indicated that the qualities of this treated wastewater could meet the first level requirements of the National Integrated Wastewater Discharge Standard (GB 8978-1996).

Key words: coagulation, PAC, ozone oxidation, hydroxyl radical, coking wastewater