Leachate refers to the liquid that results from the percolation or seepage of water through a solid waste disposal site or spoil heap. The water, in this case, comes into contact with the waste, and as it flows through, it dissolves and carries away various contaminants, including heavy metals, organic pollutants, and pathogens.

The composition of leachate varies depending on the waste materials and their age, moisture content, and the surrounding environmental conditions. In some cases, leachate can contain toxic substances that pose a significant risk to human health and the environment.

Leachate management is crucial in waste disposal operations, as the untreated discharge of leachate can contaminate groundwater, surface water, and soil, and ultimately harm human and animal health. Proper management practices include containment systems, treatment processes, and monitoring of leachate to ensure it does not pose a threat to the environment.