CHARACTERIZATION OF LANDFILL LEACHATE AND EFFECTS OF PARAMETERS OPTIMIZATION ON THE QUALITY OF EFF LUEN T S BASED ON F e2' ACTIVATED PERSULF ATE

摘要

Biological technology is the most preferred and most widely used approach for landfill leachate treatment. However, after treatment, there are residual persistent pollutants in the effluent, which required for remediation prior to discharge into environmental media. The use of transition metal ion to activate persulfate (PS) for the generation of sulfate radicals (SO4· - ) was adopted to investigate the oxidation efficiency of Fe2+/Na2S2O8 system on the removal of chemical oxygen demand (COD) and color in the leachate biochemical effluent samples. The effects of different variables on the oxidation efficiency, including oxidant dosage, catalysts dosage, pH value, and reaction time, were optimized by the orthogonal experiment. The influence degree of various factors was shown as following: Na2S2O8 dosage ! pH ! Fe2+ dosage ! reaction time. The COD and color removal were 60 and 95 when the optimal conditions were 4.0g/L Na2S2O8 dosage, 1 g/L Fe2+ dosage, pH 4, and 12 h reaction time. Through the analyses of three-dimensional excitation-emission matrix fluorescence spectrum (3DEEMFS), ultraviolet-visible spectra (UV-vis), and Fourier Transform infrared spectroscopy (FTIR), it can be found that the aromaticity and substituent groups of the organic pollutants in the wastewater sample were lessened in a large part after the treatment of Fe2+/Na2S2O8 system. The activation of PS with Fe2+ was an alternative technique for the treatment of leachate biochemical effluents, and a good removal efficiency of COD and color would be achieved under the optimal conditions.