ABSTRACT
The main long-term emissions from landfills are leachate and gas. While the gas phase can be controlled to a high degree and environmental effects are limited, leachate control is much more difficult. Leachate is the medium by which soluble materials inside a landfill may subsequently be transported into the environment. In the construction of barrier systems different kind of materials, either natural or synthetic, can be used individually or as component of a composite manufact, according to the different functions required. In recent years synthetic materials have been used increasingly to enhance soil behaviour properties. These materials are able to perform many of the functions required of a barrier system in a landfill unit. Geonets and geocomposite drains have been proposed for drainage and collections but their efficiency is disputed, particularly when used as primary drainage system. Mechanical protection of synthetic liners can be achieved by layers of sand or small-sized rounded gravel.
