Leachate: What is it, where is it found and how it can affect your landfill?
Leachate is defined as a type of pollutant created by water passing through a solid waste material generated within municipal confines. This discharge is created by the change in the physical, biological, or chemical waste products which are exposed to water, or other liquids while they’re disposed of stored in waste plants, landfills, or treatment zones. This discharge is often toxic and hazardous in nature, and depending on the site at which it is being generated can pose a huge risk to human life, vegetation and animals being exposed from it. When leachate is produced at the site of landfills, it seeps into the ground water, and adjacent soil leading to a number of problems –right from creation of toxic fumes, destroying the soil, to contaminating the ground water. Leachate treatment and disposal is a cause of concern for many municipal bodies around the world due to its toxic nature and potential for damage. Before leachates were identified as pollutants, given the huge amounts of waste being generated, there have been several instances where these liquids have led to health issues for communities surrounded by contaminated ground and surface water.
Common problems with handling leachate in landfills:
Since landfills are typically repositories of human waste, which includes a wide range of waste types, it’s not possible to plan the type of leachate which can be potentially generated. While most municipalities around the world aim to separate all types of waste, there are still several unknown aspects which lead to unpredictability in the interaction of soil, water, and the waste being disposed at the landfill site, or other sites of segregation. Leachate liquid typically contains chemicals, liquids, and other particles in varying concentrations, and therefore must be suitably separated from the waste where it’s being generated often, due to anerobic activity over sustained periods of time. As a result, when landfills are being constructed, there is a need to create a separate area for leachate collection, to minimise the interaction of this liquid with the layers of soil, underneath the landfill site. The collection site further must be such that it remains impervious and doesn’t allow for leakage of liquids.
How can leachate be handled with geotextiles?
With geotextiles, or geosynthetic liners, the creation of a separation layer at landfill sites becomes easier. These liners create a non-biological, physical and chemically resistant barrier between the site and the liquid being generated from the whole landfill site. This collection pool can be further covered, and once the liquid is gathered it can be suitably treated further to reduce its toxicity before being released into the environment. At Strata Geosystems, in addition to the use of geotextiles for leachate drainage and collection, we have also evolved the use of a gas detection layer at landfill sites to offer another layer of safety and protection. By being able to separate gas and liquids at the site, we’re able to create a safer landfill site –whether it needs to be expanded, capped, or widened, and improves the overall quality of the natural resources surrounding the landfill site by the addition of a layer of vegetation. In case of StrataDrain™–a proprietary product manufactured by Strata Geosystems — is a geonet-geotextile drainage composite manufactured with high-density polyethylene (HDPE) geonet and polypropylene, which is designed to withstand the most aggressive soil and chemical exposure in addition to the physical strain of the product at time of installation. This resistant material is one of the most widely used geocomposites when it comes to landfills due to its dual properties of separation and filtration both, allowing for liquid and gases to pass simultaneously.