Landfill leachate analysis from selected landfill sites and its impact on groundwater quality, New Delhi, India

Managing leachates from landfills in India is an important economic and environmental concern. Due to the exponential growth of population, industrialization and urbanization, several types of byproducts have been generated from day-to-day life. These byproducts are dumped in a haphazard or unempirical manner into the open space, which causes an alarming state of problem in developing country like India. In Indian context, in one of the major metro cities like New Delhi, the landfill techniques have been said to be a menace to the health of nearby residents. The present study has been undertaken to assess the environmental hazards that municipal solid waste landfill leachate poses to the groundwater. Three landfill sites, Bhalswa, Okhla, and Ghazipur of New Delhi, have been selected to determine the physicochemical properties, including significant metals of lowland leachate. Furthermore, the leachates from three different dumpyards have been compared with the permissible limits prescribed by Environmental Protection Agency, 1986. Thus, the present research findings focus for the Bhalswa landfill site leachate analysis, which indicates a high biochemical oxygen demand concentration of 3356 mg/L and chemical oxygen demand concentration of 5942 mg/L, respectively. However, the total dissolved solids, electrical conductivity, and ammonical nitrogen concentrations have been 12,384 mg/L, 32,600 µmho/cm, and 36.6 mg/L. It is observed that the Ghazipur landfill site was highly tainted as compared to Okhla and Bhalswa landfill sites. Further, quantitative analysis deduces the trend of heavy metals concentration of iron, nickel, zinc, arsenic, and chromium in the order of Bhalswa > Okhla > Ghazipur landfill sites. The toxicity hazard of dumpsites from Bhalswa, Ghazipur, and Okhla was also examined using the leachate pollution index, and the values were obtained such as 21.57, 26.61, and 20.28, respectively. Additionally, the present study reveals that the leachate percolating through all the landfill sites exceeds the permissible limits prescribed by Environmental Protection Agency, 1986, and thus, an immediate attention is required to circumvent its other adverse effect on the nearby area and groundwater reserves.