Leachate is any liquid that, in the course of passing through matter, extracts soluble or suspended solids, or any other component of the material through which it has passed. It is a liquid that drains or leaches from a landfill and varies widely in composition depending on the age of the landfill and the type of waste it contains. Leachate is a highly contaminated liquid that is generated from water percolating through a solid waste disposal site, accumulating contaminants. Leachate is associated with stockpiled coal and with waste materials from metal ore mining and other rock extraction processes, especially those in which sulfide-containing materials are exposed to air producing sulfuric acid, often with elevated metal concentrations.
Leachate can cause pollution if it reaches groundwater or seeps into nearby bodies of surface water. To ensure that leachate does not cause pollution, landfill sites have two impermeable liners and leachate collection systems. The double leachate collection system sits on top of the composite liner and removes leachate from the landfill for treatment and disposal. Operating practices include compacting and covering waste frequently with several inches of soil.
In summary, leachate is a liquid that drains or leaches from a landfill and is highly contaminated. It can cause pollution if it reaches groundwater or seeps into nearby bodies of surface water. To prevent pollution, landfill sites have two impermeable liners and leachate collection systems.
