Assessment of Landfill Leachate and Its Surface and Subsurface Migration: Experimental and Numerical Investigations

Abstract The present study focuses on assessing geoenvironmental contamination due to the leachate from the Achan landfill, Srinagar, Jammu, and Kashmir, receiving 500 t per day (TPD) of municipal solid waste. The leachate produced from the landfill either finds its way into the open expanses forming leachate pools contaminating the soil and groundwater below or drains directly into the nearby stream via surface drainage. In the present study, for heavy metals detection, triplicate samples were acidified (pH < 2), kept in a refrigerator at 4°C, and filtered before testing them with an atomic absorption spectrophotometer (Agilent, Model 240 FS), as per the recommendation of U.S. Environmental Protection Agency. Lead (Pb2+) was identified as the prominent heavy metal contaminant in the leachate which is a widely used toxic and carcinogenic heavy metal. With improper disposal and high solubility in water, Pb2+ finds its way to the surface and subsurface water bodies, contaminating them. The geotechnical parameters of the soil at the site, physicochemical properties of leachate and water samples, pollution indices, sorption studies using response surface methodology, and numerical modeling of subsurface migration of Pb2+ were investigated. The analysis of variance (ANOVA) technique was also used to determine the significance of various independent variables and their impact on the percentage of Pb2+ removal. The subsurface migration of Pb2+ through local soils was modeled using HYDRUS and validated by the one-dimensional vertical column tests. The removal efficiency of the local soil was in the range of 70% to 100% for different adsorbent dosages. The current study concludes that such encouraging removal efficiency indicates that the remediation of untreated leachate draining into the river stream should take precedence over the flooded leachate pool in the landfill. Practical Applications This work addresses a fundamental issue with the Srinagar Municipal Corporation regarding Srinagar city’s only landfill. Given the corporation’s funding constraints, gradual steps must be planned and executed. This work was performed by considering the hazards associated with the nonmaintenance of the landfill site and the dire need for a new fourth cell for the scientific dumping of waste, which would relieve the highly overloaded Cell-2. Over and above, the work has quantified the hazardous heavy metals, hazardous physicochemical characteristics of the leachate, and its ef