Leachate
Leachate is the liquid produced when water percolates through any permeable material. It can contain either dissolved or suspended material, or usually both. This liquid is most commonly found in association with landfills, where rain percolates through the waste and reacts with the products of decomposition, chemicals and other materials in the waste to produce the leachate. If the landfill has no leachate collection system, the leachate can enter groundwater, and this can pose environmental or health problems as a result. Typically, landfill leachate is anoxic, acidic, rich in organic acid groups, sulfate ions and with high concentrations of common metal ions, especially iron. Leachate has a very distinctive smell which is not easily forgotten.