A landfill liner, or composite liner, is intended to be a low permeable barrier, which is laid down under engineered landfill sites. Until it deteriorates, the liner retards migration of leachate, and its toxic constituents, into underlying aquifers or nearby rivers from causing potentially irreversible contamination of the local waterway and ...

A geosynthetic clay liner (GCL) is comprised of two geotextiles that are needlepunched together, encapsulating a layer of sodium bentonite clay between them. GCLs are known for having consistent, very low permeability.

A thick plastic layer forms a liner that pre-vents leachate from leaving the landfill and entering the environment. This geomem-brane is typically constructed of a special type of plastic called high-density polyeth-ylene or HDPE.

However, most landfill cell liner systems share common features like multiple layers of material. Some projects call for just three to four layers of material to trap leachate, while others can use seven or more distinct layers.

Textured LLDPE or HDPE geomembrane on a prepared sub grade covered with a geocomposite drainage layer is the most common closure system for closed landfill cells. These two layers of geosynthetic products are then covered with a soil cover, which is seeded to prevent soil erosion.

What Types of Liners Are Used in Landfills? Clay liners are typically the only type of natural liner that is suitable for use in a landfill, although they aren’t used on their own. Dense, highly compacted clay has low permeability and can be used to line the bottom and sides of a landfill.

Geosynthetic clay liners (GCLs) are factory manufactured hydraulic barriers consisting of a layer of bentonite or other very low-permeability material supported by geotextiles and/or geomembranes, mechanically held together by needling, stitching, or chemical adhesives.

Geosynthetic clay liners (GCLs) represent a relatively new technology (developed in 1986) currently gaining acceptance as a barrier system in municipal solid waste landfill applications. Federal and some state regulations specify design standards for bottom liners and final covers.

The most critical components of a landfill cap are the barrier layer and the drainage layer. The barrier layer can be low-permeability soil (clay) and/or geosynthetic clay liners (GCLs). A flexible geomembrane liner is placed on top of the barrier layer.

Liner installation consists of seven layers of protection that ensure our landfill is safe and sanitary. View our slideshow to see the whole process of installing the liner in a new landfill cell.