what is the purpose of landfill liner?

A landfill liner, or a composite liner, is  a low permeable barrier, which is laid bottom under engineered landfill projects. The landfill  liner retards migration of leachate, and its toxic constituents, into underlying water or nearby rivers. Modern landfills generally require a  compacted clay, overlaid by a high-density polyethylene HDPE geomembrane.

What are landfill liners made of?

The landfill liner is also known as the ‘bottom liner’, the landfill lining is made of a synthetic material or clay. It is important to consider the material of the product to make sure that it can efficiently prevent toxic and leachate from migrating to the soil,  water. Some landfill liners are also used as capping cover. Capping covers provide secondary protection against contamination. Meanwhile,landfill capping covers can help retain gas, which are produced by toxic byproducts. The gas then be used for electricity conversion.

Why are liners laid down at the bottom of a landfill?

The landfill’s major purpose is to contain the waster. The landfill bottom liner prevents the waster from migrating to  the soil, espicially the groundwater. The liner is usually durable, puncture-resistant synthetic plastic (polyethylene, high-density polyethylene, polyvinylchloride). It is usually 30-100 mils thick. The landfill liner may be also be combined with clay soils as an additional liner. The landfill liner may also be protected on each side by geotextile that can  help to keep the landfill liner from tearing or puncturing from the  rock and gravel layers.