What happens to our rubbish - Landfill
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What is a landfill site?
A ‘ landfill site’ is a hole in the ground that is filled with rubbish. A ‘landrise site' is where rubbish is piled on the land where there is no hole. The pictures below show a Devon landfill in an old quarry, and Malta's highest point, a landrise site.
Some people insist that they do not like landfill sites; however, beyond how they look, there is little wrong with a modern well engineered site. Modern day landfill sites (from late 1980’s onwards) are well engineered to hold rubbish, liquid and gas and inspected regularly. Landfill sites deal with waste safely, as a last resort.
What are the main problems with landfill sites?
1) The speed we fill them up.
There are three ‘active’ landfill sites in Devon at Heathfield, Broadpath and Deepmoor. These sites have about 7 years available space remaining until they are either full, or need further planning permission to extend their life. Devon’s largest landfill site accepts approximately 1,000 tonnes a day.
Devon also has 55 old landfill sites; 18 of which are still monitored regularly to make sure that they do not cause pollution. Old sites must be monitored until they are no longer considered a risk to the environment, which could be hundreds of years!
In England and Wales, there are almost 500 landfill sites estimated to contain 615 million cubic metres of rubbish. Whilst this country does have some very large landfill sites, the biggest tend to be found in the tropics and southern hemisphere. Some of the largest sites deal with over 10,000 tonnes every day, and can be up to 200 meters deep!
Some scientists believe that the worlds biggest landfill is not actually on land, it is in our Oceans and known as the Great Pacific Garbage Patch!
2) Pollution
A landfill site is not a treatment site. It simply contains waste safely in one place.
When a section of a landfill site is being filled (an ‘active cell’) it has no cover, so large amounts of rain collect in it. This 'Landfill liquid’ is known as leachate and is potentially very polluting, and expensive to treat. An average landfill may produce up to 150m3 of leachate every day which is equivalent to the amount of water a typical household uses every year. Once a cell is filled, it has a cover put on it to reduce this problem.
Our rubbish also contains ‘organic’, or compostable material such as food and garden waste (see ‘ What’s in a typical dustbin’). Compostable things in a landfill site produce a greenhouses gas called methane. Whilst some landfill sites capture methane to generate energy, they are not able to capture all of it, because it is a gas. If the gas could be captured and converted to energy, a typical landfill could provide enough electricity to power 20,000 homes.
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In order to fit more in, rubbish in landfill sites is regularly squashed. This squashing, removes air which leads to the landfill becoming anaerobic (without air). Unlike ‘composting’ which is an aerobic process (with air), different bacteria get to work. Anaerobic bacteria produce methane whereas aerobic bacteria do not. This is why composting is good for the environment but compostable waste in landfill sites is not.
Why do we still use landfill sites?
We use landfill sites because we continue to throw away a lot of rubbish and they are very convenient.
However, there are a number of reasons why we are not using these sites as much as we used to;
1) Legislation to reduce the amount of rubbish buried in these sites was introduced in 1999 through the EU Landfill Directive. This directive limits the amount and type of rubbish (such as organic waste) that can be buried, and because of it, there are now very few families in Devon who do not have a recycling collection service from their houses.
2) There is also pressure on landfill sites through increasingly tight environmental controls which has led to many smaller sites closing. This has resulted in the bigger sites taking more rubbish from a wider area. In addition, certain sites are only licensed to take certain types of rubbish depending, among other things, on the engineering and geography of the site.
3) Depending on the site, it costs around £35 for every tonne of rubbish delivered to a landfill site (a dustbin lorry will contain around 10 tonnes). However, landfill tax is also charged at £56 per tonne (2011/12). Landfill tax, aims to reduce our use of landfill sites and will increase by £8 every year until it costs at least £80 per tonne. At this point, it will cost over £120 to bury 1 tonne of rubbish in a landfill site.
This website is intended to provide a broad introduction to waste management in Devon, if it doesn’t answer all your waste questions, please contact us via the ‘Ask a question’ page on this site and we will do our best to answer it.
