ADLib Glossary (J to L)

More Information:

Landfill and Landfill Gases

Landfill

A waste disposal site for the deposit of waste onto or into land. This includes:
  1. internal waste disposal sites where a producer of waste is carrying out its own waste disposal at the place of production; and
  2. a permanent site (i.e. more than 1 year) which is used for the temporary storage of waste

A method used for both domestic waste and more hazardous chemicals. Landfill sites used for difficult and potentially dangerous wastes are now engineered, managed and monitored to prevent pollutants being released (see Landfill Gas below).

Landfill sites are thought to contribute to many environmental problems:

  • Releases toxins - Rotting rubbish emits explosive gases and polluting liquids. Methane emissions contribute to climate change.
  • Threatens our quality of life - Landfill creates problems for local communities. Nuisances include more traffic, noise, odours, smoke, dust, litter and pests.

In addition land suitable for these sites is now in short supply - moving them further away from towns and cities increases the cost of transporting waste to the disposal site and so increases the cost to householders and businesses.

Landfill Gases

The degradation of domestic and other wastes in landfill sites under anaerobic conditions results in the generation of a gas which is predominately composed of methane and carbon dioxide in the ratio of 65:35. The gas also contains trace components, at parts per million levels, of organic compounds. It has theoretically been estimated that each tonne of domestic refuse disposed of at a landfill site can potentially give rise to between 400 and 500 m3 of gas. In practice, however, the actual yield is much less at around 200 m3. In recent years moves have been made to exploit this gas by virtue of its methane content. Some such schemes include using the gas for electricity generation, heating of greenhouses and industrial premises, and brick and cement production.

Methane is potentially explosive when present in air at concentrations between 5% and 15%. There have been several incidents in the UK where the uncontrolled generation of the gas has resulted in explosions causing substantial loss of property and personal injury. There is now a high awareness of the safety and environmental risks associated with the gas.

Landfill Site (plus schematic):

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