Characteristics and Pollution Potential of Leachate from Municipal Solid Waste Landfills

Landfill leachate occurs as one of the by-products of waste deterioration. It is the mineralization of pollutants within the waste stream which gives rise to a very concentrated, dark and toxic chemical mix, depending on the type of waste disposed, age of dumpsite and climatic conditions of the site. Leachate is generally collected at the bottom of the landfills, in unlined landfills, leachate usually migrates through the underground strata and may travel down to the groundwater table. Some lateral migration of the leachate is also possible depending on the surface and subsurface geology. The migrating leachate can dissolve soluble chemicals, many with toxic constituents that may result in soil and water resources pollution. Hence proper leachate management procedures should be developed and incorporated into the design of landfills.