Assessment of Impact of Leachate on Groundwater, in the Vicinity of the First Engineered Landfill Site in Delhi, India
Keywords:Leachate Pollution Index, Groundwater characterisation, Narela-Bawana landfill, correlation matrix, Integrated Municipal Solid Waste Management Facility, Engineered landfill site
The dumping of solid waste in sanitary landfills can cause significant impacts on the environment and human health. The main concern is focussed on the pollution potential due to movement of the leachate generated from these landfills into the groundwater, surface water or the sea. Hence, to decide whether the leachate is to be collected and treated, or may be allowed to discharge into the adjoining soil or public sewer or surface water body, it is essential to have the assessment of its composition, strength and its variation with time and space. In this paper, the experimental work carried out at the first engineered landfill site in New Delhi, India, to ascertain the composition of leachate, and its effect on the groundwater under the existing scenario, is presented. For asserting the contamination potential of the landfill site, a tool called Leachate Pollution Index (LPI) has been used. LPI is an increasing scale index, where a higher value indicates poor environmental condition, developed based on the Rand Corporation’s Delphi Technique; which is an opinion based research technique to extract information from a group of panellists. LPI includes 18 parameters, out of which the leachate samples were analyzed for 16 parameters viz. pH, TDS, BOD5, COD, TKN, Ammonia nitrogen, Total Iron, Copper, Nickel, Zinc, Lead, Total chromium, Mercury, Arsenic, Chlorides and Cyanide. The groundwater samples collected from the vicinity of the landfill were analyzed for 12 parameters viz. pH, TDS, Chlorides, Total iron, Arsenic, Cyanide, Lead, Zinc, Copper, Total chromium, Mercury and Nickel. In order to determine the factors which had higher detection rate and larger impact, the Pearson correlation matrix has been developed among the parameters tested of groundwater samples. Results clearly indicated that the likely contamination of groundwater due to leachate released from the landfill. Results are further compared with Bureau of Indian Standards and standards laid down by World Health Organisation (WHO), for drinking water. Presence of contaminants in groundwater particularly near the landfill sites warns its quality and thus renders the associated aquifer unreliable for domestic water supply and other uses.