leachate

References

leachate

liquid contaminant

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

June 30, 2026

Quick Summary

Leachate is a liquid formed when water percolates through decomposing organic matter, such as in a sanitary landfill. This liquid can dissolve and carry soluble components from the waste. If leachate contaminates groundwater or seeps to the surface, it can cause significant environmental pollution and contaminate drinking water supplies.123

Controlling leachate is a crucial aspect of sanitary landfill design and operation. Methods include preventing surface water from entering the landfill and using impermeable liners to separate the waste from groundwater. Modern landfills also incorporate leachate collection and treatment systems. The term "leachy" describes soil that permits liquids to pass through easily due to its porous nature.24

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

6 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

hazardous-waste management
Secure landfills
…have two impermeable liners and leachate collection systems. The double leachate collection system consists of a network of perforated pipes placed above each liner. The upper system prevents the accumulation of leachate trapped in the fill, and the lower serves as a backup. Collected leachate is pumped to a treatment…
Read More
…have two impermeable liners and leachate collection systems. The double leachate collection system consists of a network of perforated pipes placed above each liner. The upper system prevents the accumulation of leachate trapped in the fill, and the lower serves as a backup. Collected leachate is pumped to a treatment…
Read More

solid-waste management
Controlling by-products
A highly contaminated liquid called leachate is another by-product of decomposition in sanitary landfills. Most leachate is the result of runoff that infiltrates the refuse cells and comes in contact with decomposing garbage. If leachate reaches the groundwater or seeps out onto the ground surface, serious environmental pollution problems can…
Read More
A highly contaminated liquid called leachate is another by-product of decomposition in sanitary landfills. Most leachate is the result of runoff that infiltrates the refuse cells and comes in contact with decomposing garbage. If leachate reaches the groundwater or seeps out onto the ground surface, serious environmental pollution problems can…
Read More

water pollution
Effects of water pollution on groundwater and oceans
…or unlined landfills or lagoons; leachates from unlined municipal refuse landfills; mining, fracking, and petroleum production; and leaking underground storage tanks below gasoline service stations. In coastal areas, increasing withdrawal of groundwater (due to urbanization and industrialization) can cause saltwater intrusion: as the water table drops, seawater is
Read More
…or unlined landfills or lagoons; leachates from unlined municipal refuse landfills; mining, fracking, and petroleum production; and leaking underground storage tanks below gasoline service stations. In coastal areas, increasing withdrawal of groundwater (due to urbanization and industrialization) can cause saltwater intrusion: as the water table drops, seawater is
Read More