A study on the treatment of landfill leachate using chemical coagulation and fenton oxidation

초록

The objectives of this study are to determine the optimal operation condition of chemical coagulation with ferric chloride and fenton oxidation for effluents of a biological denitrification treatment and an existing lagoon treatment of landfill leachate, and to investigate the influence for removal efficiency of COD affected by effect of alkalinity on fenton oxidation, and to set up optimum operation condition of chemical coagulation and fenton oxidation of landfill leachate. In jar-test, optimum dosage of ferric chloride for removal of COD was 1,500mgFe3+/L and removal efficiencies of CODCr and CODMn under this condition were about 55% and 64%, respectively. After chemical coagulation using ferric chloride of biological treatment effluents, it was most efficiently treated with Fenton oxidation at 1.5 of Fe2+/H2O2 ratio, in terms of 600 mgFe2+/L of ferrous sulfate and 400 mgH2O2/L of hydrogen peroxide. Also, when the more alkalinity increased, the more removal efficiency of COD decreased rapidly. When applied the experimental result of chemical coagulation and fenton oxidation of effluents to Sudokwon landfill leachate treatment plant, optimal dosage of ferric chloride was 450 mgFe3+/L such that CODCr could be removed up to approximately 60%. When injecting ferrous sulfate 240 mgFe2+/L and hydrogen peroxide 130 mgH2O2/L into fenton oxidation after chemical coagulation treatment, removal efficiency of CODCr was about 31% and quality of water was acquired stably as 185 mgCODCr/L.