ENHANCED IN-SITU REDUCTION OF LEACHATE PARAMETERS DUE TO AERATION AND LEACHATE RECIRCULATION IN PILOT SCALE MSW BIOREACTOR LANDFILL MODELS IN TROPICAL CLIMATE

The processes for optimizing toxicity removal of leachate from pilot scale Municipal Solid Waste bioreactor landfills were attempted. Landfill models were simulated in Fibre Reinforced Plastic tanks of size 1.5m x 1.0m x 1.0m by applying interventions like aeration and leachate recirculation. It was found that the Chemical Oxygen Demand and Biochemical Oxygen Demand values increased till 46th week after which the values started reducing. On 89th week after closure of landfill, the aerobic landfill model showed the minimum values for COD (10,200 mg/l) and both anaerobic and aerobic models with leachate recirculation had the lowest BOD (4934 mg/l). By 116th week the least concentrations of COD and BOD were in anaerobic landfill model with leachate recirculation (64 and 22 mg/l). Ammonia Nitrogen was the least in aerated model with leachate recirculation by 116th week from closure (281 mg/l). Conductivity was less in the landfill models with leachate recirculation (4.2 and 5 mS/cm for anaerobic and aerobic respectively).