Assessment of Contamination Potential in Okhla Landfill, New Delhi by using Leachate Pollution Index

Abstract

Landfill leachate generation from a landfill site is one of the main problems for both developed and developing countries around the world. Leachates liberated from the site contain various organic, inorganic, heavy metals, and sometimes hazardous chemical and organic pollutants, which are the origin of the deterioration of air and water quality in its vicinity. The present attempt was performed to assess seasonal variation of the leachate quality, and also determine three sub-indices of leachate which are LPIorg, LPIin, and LPIhm, and the overall LPI of operational, uncontrolled landfills in South Delhi by using leachate pollution index (LPI). Around twenty-five (25) parameters were analyzed during pre-monsoon, monsoon, and post-monsoon seasons from the collected leachate samples. Out of twenty-five pollutants, COD, BOD, NH4-N, EC, and TDS were found beyond the set standard limit in all seasons. Other pollutants like TKN, TSS, TCB, and Cl were also found in high concentrations. Arsenic (As) concentration was found beyond permissible during post-monsoon. The concentration of lead (Pd) in the pre and post-monsoon season was observed beyond the standard limit. Sub-LPI indices in the pre-monsoon season were observed as LPIorg 82.0, LPIin 40.8, and LPIhm 6.9, and likewise, Sub-LPI in monsoon season were LPIorg 81.4, LPIin 25.5, and LPIhm 5.2 and Sub-LPI post-monsoon season was calculated as LPIorg 90.5, LPIin 30.2 and LPI hm 6.2. Almost in all the seasons, LPIorg i.e. organic pollutants was dominated then followed by LPIin, and LPIhm. The overall LPI value of the study area during the pre-monsoon, monsoon and post-monsoon was 32.5, 28.2 and 32.0, respectively. It was observed that overall LPI (calculated) was maximum during pre-monsoon followed by post-monsoon and monsoon. LPI value was beyond the standard limit, except for LPI hm, which was below the standards. It was recommended that more waste-to-energy plants and decentralized waste segregation units need to be set up, to avoid direct dumping of all mixed waste in the landfill sites.