Leachate

Author: Jeff le Roux ~ Enviroserv

( Article Type: Explanation )

Leachate is the liquid that is formed and drains out of a landfill site. It is derived from three sources:

• Liquid waste disposed on site
• The natural liquid product of waste decomposition
• Rainfall and storm water catchment entering the site.

Liquids percolate down through the waste body and in the process dissolve and carry organic and inorganic compounds in the waste creating a highly contaminated and potentially toxic liquid (landfill leachate). This liquid is collected in the leachate collection system of the landfill cells and stored in ponds.

Leachate is often the source of undesirable odours emanating from landfill sites. Aerators can be installed into leachate dam to minimise odour problems, enhance biological degradation and encourage evaporation. Special aspirating sub-surface aerators, which result in air being drawn down into the leachate, rather than the more familiar aerators used at sewage treatment plants, result in considerably lower odour formation.

Non-toxic leachate can be used on site to control dust by spraying access roads and working areas.

Normally, leachate would be treated chemically and released into the sewer system once approved quality standards have been achieved.