| Abstract |
| The purpose of this study was the effect of the advanced treatment such as DOF (Dissolved Ozone Flotation) on the reduction of the non-degradable COD (Chemical Oxygen Demand) in the wastewater from the electronics manufacturing industry. We also developed a prediction model of effluent COD in the DOF process. For reasons relating to economical operations, proper ozone dosage was selected by analyzing the water quality of discharged water with the change of ozone dosage. The decomposition characteristics of COD by ozone were evaluated by molecular weight distribution analysis and DOC (Dissolved Organic Carbon) concentration measurement. As a result of analyzing the treated water quality in the range of ozone dosage of 4 ~ 10 O3 mg/L, 4.0 O3 mg/L was estimated to be the optimum ozone dosage and it was adversely influenced by additional injections. As a result of the analysis of the DOF treated water, the DOC of lower than 1,000 Da was 1.344 mg/L, which was 21.4% higher than that of the secondary treated water, and the DOC of higher than 10,000 Da was 0.735 mg/L, which was 10.1% lower than that of the secondary treated water. The results found that the DOF effectively reduced the large molecular weight fraction of DOC. Therefore it is possible to stably satisfy the effluent discharge limits including COD. Multiple regression analysis found that the temperature, COD and SS (Suspended Solids) concentration of the secondary treated water had a great influence on the COD removal efficiency by the DOF process. The results of multiple regression analysis predicted the effluent COD from DOF process with a reliability coefficient (R2) of 0.71. |
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| Key Words |
| Dissolved ozone flotation, Electronics wastewater, Molecular weight distribution, Multiple regression analysis |
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