Leachate Characteristics of Aged Soil-Like Material from MSW Dumps: Sustainability of Landfill Mining

Abstract

Soil-like material (SLM) constitutes the largest component of reclaimed material from old municipal solid waste (MSW) dumps, often exceeding 50% of the excavated material. One attractive option for use of this material is bulk applications in earthfills instead of natural soil. This paper presents the leaching characteristics of soil-like fraction (finer than 4.75 mm) of aged municipal solid waste excavated from three old dumps of India. The leaching behavior of this soil-like fraction was assessed to examine its use as an earthfill. The total dissolved solids (TDS), chemical oxygen demand (COD), release of color, and ammoniacal nitrogen in the leachate from soil-like material were found significantly higher in comparison with the water extract of local soil. Relatively elevated concentration of some metals (arsenic, chromium, copper, cobalt, and nickel) were observed in the leachate from soil-like material in comparison to the water extract of local soils. The study indicates that the soil-like fractions obtained from landfill mining have to be screened for physicochemical characteristics and pollution potential before using them as an earthfill.