Advanced Treatment of Landfill Leachate by Micro-electrolysis and Photocatalytic Oxidation

In the past, the landfill leachate in the municipal solid waste landfill was treated by biochemical methods, but output wastewater could not reach standards.It is a cost-effective method to properly improve the former treatment process in order to meet the objective.In this paper, a novel route for the advanced treatment of the landfill leachate after biochemical treatment was proposed viairon-carbon micro-electrolysis and photocatalytic oxidation.The expermental parameters of micro-electrolysis including pH, processing time, iron-carbon ratio and particle size of iron pellet were examined and optimized.The results showed that when the optimal conditions were: pH=4.5, retention time=120 mins, iron-carbon ratio=2, and with small iron fillings pellet(rubs fillings), the removal rates of COD_cr and chroma in the landfill leachate reached 71.2% and 97.0%, and the removal rates of BOD₅ and NH4-N in the landfill leachate reached 70.8% and 67.5%, respectively.The output wastewater was further treated using photocatalytic oxidation.Finaly, the COD_cr value in waste water was only 52.8mg/L, the removal rate of COD_cr in the leachate reached 94%, the removal rates of BOD₅, NH4-N and chroma in the landfill leachate reached 80%, 73.9% and 98%, respectively.The proposed procedure was applied to treat landfill leachate with satisfactory results.