IMPACT OF LEACHATE ON GROUND WATER QUALITY NEAR OKHLA LANDFILL SITE, NEW DELHI, INDIA

Abstract

The quality of ground water in the areas adjacent to the solid waste disposal sites i.e. Okhla landfill was examined in order to evaluate interactions and the possibility of groundwater contamination as a result of percolation of the leachates generated in the Solid Waste Disposal sites. Leachate generated in the landfills tends to drift from the landfill waste resulting in contamination of groundwater and underlying soil consequently making landfills, the potential source of groundwater contamination. An integrated approach to the examination was employed in the study. This included Ground water and leachate sampling; and laboratory-based instrumental and experimental analyses. Concentration of various physical parameters and chemical species determined in leachate samples and ground water and includes-pH total dissolved solids (TDS), Chemical Oxygen Demand (COD), Biochemical oxygen demand (BOD), Total Hardness (TH),Calcium Magnesium, chloride (Cl-), Sulphate(SO42-), Phosphate (PO43-), heavy metals (Fe, Mn, Cr, Co, Ni, Cu, Zn, As, Cd, Pb).The measured concentrations of TDS (540 mg/l), Fe (0.46mg/L), Ni (0.06 mg/L), Pb (0.063 mg/L), COD (3.2 mg/L) is above the permissible limit in the ground water sample, which indicates that the leachate percolation has influence on the Groundwater quality. Further they can act as tracers for the groundwater contamination. Presence of heavy metals in leachate supports the toxicity data The physical-chemical concentrations in groundwater samples were not as high as in leachate samples, thus indicating that chemical constituents in leachate are attenuated as they percolate through the aquifer into the groundwater system. Some remedial measures are also suggested to reduce further ground water contamination via leachate percolation.