Landfill

Landfill Overview

"Landfill is still the principal means of managing most of the waste, although landfilling of municipal waste has decreased (in England) from 79% in 2000/01 to an estimated 55% at the end of 2007 Around 44% of industrial and commercial waste is also managed by landfill. The Landfill Directive has set targets of reducing the amount of waste going to landfill and the Landfill Tax was introduced in 1996 in an attempt to reduce the amount of waste going to landfill. However, landfill will always be an important option for certain domestic, commercial and industrial wastes produced in the UK." (Environmental Services Association)

Landfill Gas (Methane)

One tonne of biodegradable waste produces between 200 and 400 cubic metres of landfill gas. Waste treatment, including landfill, released nearly 32% of the UK's methane emissions in 2004. About a third of the 500 landfill sites taking significant amounts of biodegradable waste have gas controls and many sites extract the gas for energy recovery.  About 28% of renewable gas and electricity now comes from landfill gas in Great Britain (Environmental Services Association). Burning the methane produces carbon dioxide, which has a much lower insulation potential. Extending these measures will reduce methane emissions over the next 10 years.

Methane is around 21 times more potent than carbon dioxide and allowing methane to escape into the atmosphere would have significant climate change implications. As the last decade has witnessed, increasingly landfill gas is being used to generate electricity or heat. Over the last decade, waste managers have reacted to a combination of the need to reduce greenhouse gas emissions, whilst recovering higher value from the waste stream. As electricity generation from landfill has increased, emissions from the sites have fallen.

Between 1990 and 2005 methane emissions  from landfill escaping into the atmospherefell by 61%.

Landfill Leachate

During landfill site operation, a liquid known as 'leachate' is produced. This is a mixture of organic degradation products, liquid waste and rain water. Leachate is extremely variable in composition depending on the nature of waste in the landfill, the landfill design etc. but typically has high organic carbon content, high concentrations of nitrogen and is usually slightly acidic.

Landfills are designed and operate to seal the wastes as much as possible from the surrounding environment. Central to this environmental protection is avoiding groundwater contamination.