This work aims to investigate removal efficiency of oxidation and coagulation/flocculation processes, to provide an effective method for the treatment of biologically pre-treated leachate. Leachate containing 985 mg L−1 COD was treated by using three treatment schemes, i.e. oxidation, coagulation/flocculation and the combined process of coagulation/flocculation followed by oxidation. The application of single oxidation resulted in the effective removal of COD and color up to 80.4 and 83.2%, respectively. However, residual COD values lower than 200 mg L−1 could only be achieved under intensive experimental conditions (high dosage of Ca(ClO)2 and prolonged oxidation time). Coagulation/flocculation yielded residual COD values higher than 200 mg L−1 even at the optimum coagulation conditions. The combined treatment by coagulation/flocculation followed by oxidation yielded final COD lower than 100 mg L−1 at the following conditions: pre-coagulation with 250 mg L−1 PFS (poly-ferric sulfate) and over 30-min post-oxidation, or pre-coagulation with 300 mg L−1 PFS and over 20-min post-oxidation. Hence, pre-coagulation with PFS followed by oxidation with Ca(ClO)2 was recommended for advanced treatment of biologically treated leachate.
Treatment of biologically treated leachate by oxidation and coagulation
H. Y. Zhang, Y. C. Zhao, J. Y. Qi; Treatment of biologically treated leachate by oxidation and coagulation. Water Sci Technol 1 October 2011; 64 (7): 1413–1418. doi: https://doi.org/10.2166/wst.2011.377
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