Experimental research of combined ozone/hydrogen peroxide oxidative degradation of chemical oxygen demand in sauce-flavored liquor wastewater

Sauce-flavored liquor wastewater is characterized by high concentrations of complex organic compounds that resist degradation, resulting in chemical oxygen demand (COD) values well above the permissible limit of 15 mg/L despite multi-stage treatment. This study systematically optimized the operational parameters for both ozone-only oxidation and O 3 /H 2 O 2 co-oxidation using one-factor experiments, orthogonal design, and response surface methodology to evaluate their efficacy in deep COD reduction. Under optimized conditions, ozone-only oxidation achieved only a 60% COD removal efficiency, with low ozone utilization efficiency and high dosage requirements. To address these shortcomings, an O 3 /H 2 O 2 combined oxidation approach was adopted. At pH 8.5 with ozone and hydrogen peroxide dosages of 100 mg/L and 94 mg/L, respectively, the COD removal efficiency increased markedly to 78.6%, reducing effluent COD to 9 mg/L while lowering ozone consumption by 28.6%. Kinetic analysis confirmed adherence to a second-order reaction model. The O 3 /H 2 O 2 co-oxidation technology thus offers superior efficiency and cost-effectiveness for treating recalcitrant sauce-flavored liquor wastewater, presenting a promising industrial solution for the deep treatment of hard-to-degrade organic effluents.