Landfill Liner System
Landfills are designed with "cells" that are lined to prevent groundwater contamination. The liner consists of a two-foot layer of low-permeability,> re-compacted clay soil. Over this layer, a 60-mil, high-density polyethelene (HDPE) plastic liner is installed to complete the composite liner system, covering the entire bottom and sides of the landfill cell. A blanket of geotextile fabric, composed of synthetic, felt-like fibers, is laid above the primary liner system, along with a geonet made of mesh-like plastic. Together, these prevent fine clay particles from clogging the leachate collection layer and promote removal of leachate from the liner surface. Click here for a diagram illustrating the anatomy of a landfill. Strick construction guidelines must be followed in constructing the liner systems, which are summarized below: