Treatment of leachate from domestic landfills with three-stage physicochemical and biochemical technology

Because domestic landfill leachate concentrates complex organic pollutants, effective treatment of landfill leachate has gained increasing attention in recent years. In this paper, three-stage physicochemical and biochemical technology for treatment of domestic landfill leachate is presented. Based on an eight-month pilot operation, over 96% of the main pollutants, for example COD Cr , BOD 5 , SS, NH 4 + –N, coliform, and chrominance, can be removed, among which the removal efficiency of COD Cr was 89.5, 8.6, and 1.7% in stages 1, 2, and 3, respectively, and the removal efficiency of BOD 5 was 90.3, 8.3, and 1.4%. In the treatment, the biochemical process played a principal role on the removal of pollutants from the leachate. The treatment efficiency depends on how the syntheses of physicochemical, anaerobic, and hydrolytic procedures pave the way for biochemical treatment. Application of a combined efflux and mixed-flow aerator enhanced the removal efficiency during each procedure.