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| Optimization of sulfate radical-based advanced oxidation process using response surface methodology for treating effluent from biological treatment of landfill leachate |
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Abstract Generally the quality of the effluent from biological treatment of landfill leachate couldn’t meet the national discharge standard due to the relatively high concentrations of recalcitrant COD, NH4+-N and NO2--N. In this study, sulfate radical-based advanced oxidation process (SR-AOP) was adopted for the advanced treatment of the effluent. Single factor and combined effects of pH, temperature (T) and sodium persulfate concentration (SPC) on SR-AOP in removing TOC and TN from the effluent were evaluated using response surface methodology. Results showed that each factor alone could significantly influence the TOC removal but not TN. The influential extent on the TOC removal was more significant with pH, followed by T and SPC. On the other hand, both TOC and TN removal rate could be significantly impacted by the combined effect. The order in TN removal efficiency was T+SPC>pH+SPC>T+pH, whereas that in TOC removal was T+pH>pH+SPC>T+SPC. The highest TOC and TN removal rate, 35.5% and 16.9%, respectively, was obtained under the optimal condition of 0.5g/L SPC and 3.8g/L FeSO4at pH 5and 30℃ for SR-AOP in treating biological effluent from landfill leachate. In addition, BOD5/COD ratio of the effluent could also be significantly improved after SR-AOP. These results indicated that SR-AOP could be an effective method for advanced treatment of the effluent derived from biological treatment of landfill leachate.
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Received: 01 November 2014
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