Landfill

Landfill is the disposal of waste into or onto land. Today, landfill sites are constructed and operated to strict technical standards in order to reduce environmental effects. In 2005 there were 190 landfill sites in operation in Scotland.

Most types of waste may be disposed of via landfill; however the EU Landfill Directive 1999/31/EC1 requires that landfill sites must now be classified as either hazardous, nonhazardous, or inert. Reducing the amount of waste to landfill is currently being encouraged by the Landfill Directive to recover value from waste and develop more sustainable waste management.

When waste is received at the landfill it is weighed and checked to ensure it is compliant with its landfill operating permit. It is then tipped into the landfill, compacted and covered to prevent odour, litter, and pest infestations. The waste will then be gradually decomposed by microbes. This decomposition process, mixed with rainwater creates leachates and gas, which are both taken out of the landfill through a system of pipes. The leachates are then usually taken for treatment, while the gas, mainly a mix of carbon dioxide and methane, may be burnt off or used in an on-site energy generation plant which contributes energy to the national grid. When a landfill has reached its maximum capacity it is covered completely with an engineered cap, e.g. using clay and restored using soils or other covering materials so that the site can be used in the future for agriculture, amenities or nature conservation.