How does a landfill site work? (1) When waste arrives, it is weighed and its' contents checked to ensure it complies with the landfill operating licence. (2) This waste is then tipped into the ‘tipping face' of the landfill. This is then compacted by specialist machinery and covered with layers of cover material, such as soil. This layer helps to reduce odour produced by the waste and deter scavengers, like rodents, flies and birds. At the end of each day the operational area of the landfill is completely covered with a layer of cover material. (3) A common misapprehension is that waste is simply dumped and buried in landfills, but actually much of it is naturally broken down by microbes under anaerobic (absence of oxygen) conditions. This decomposition, combined with rainwater filtering through the landfill, results in the production of liquid, called leachate, and gas. (4) This gas is mostly carbon dioxide and methane and due to its harmful nature is often burnt off or directed to an on-site energy generation plant, where it is converted into electricity, which is most commonly exported to the National Grid. (5) The liquid is pumped into storage tanks where it is treated and cleaned before being discharged into the sewer. The dustbin of Europe "The Dustbin of Europe" was how the UK was described in 2007. Almost five years ago, Britain was reported as disposing of more rubbish in UK landfills than any other EU state. The Local Government Association (LGA) estimated the UK put 27 million tonnes of waste into landfills every year, 7 million more than any other country and that the area given over to landfill space was about the size of Warwick. Not just that, but we would run out of landfill space by 2016. The UK produces 434 million tonnes of waste every year. That is enough to fill the Albert Hall every two hours. Householders produce almost 30 million tonnes on average each year. 73% of this waste goes to landfill, even though 90% of it is recoverable and could be recycled, reused or composted. We're wasting food! As a country the UK is still throwing out millions of tonnes of food that goes directly into landfills. Last year, 5.3 million tonnes of food and drink that could have been consumed, were disposed of in landfills. This wasted food added up to £480 per household per year, or £680 per year for families. In total, this equates to £12 billion in food waste. It's not just the waste that damages the environment, but also the carbon emissions - the wasted food mounts up to 20 million tonnes (22 million tons) of carbon dioxide emissions. That's about 2.4 percent of greenhouse gas emissions associated with all consumption, or about the same carbon emissions of two million UK citizens each year. Waste or energy? In order to reduce the amount of rubbish that goes into landfills, the Government has implemented a Landfill Directive which lays out targets for reducing the amount of waste put into the ground. They include ensuring that by 2012, the waste sent to landfills should be 75 per cent of that sent in 1995. But how is this done? Firstly, a site is needed. Once prepared and equipped with essential containment systems and structures. These include liner systems, gas pipes, leachate collection control and monitoring boreholes. These containment, control and processing systems stay in operation for up to approximately 50 years after the landfill is closed, ensuring the landfill's stability and the protection of the environment. Landfill is still the principal means of managing most of the waste in the UK. Landfill tax was introduced in 1996 in an attempt to reduce the amount of waste going to landfill. In order to reduce the number of landfills the country has, the amount of waste we produce needs to be cut down. However, that is not easy when, currently, the largest lake in Britain could be filled with rubbish from the UK in eight months. Landfill gas (Methane) One tonne of waste tipped in a landfill produces between 200 and 400 cubic metres of landfill gas. Landfill sites released 32% of the UK's methane emissions in 2009. Methane is about 21 times more potent than carbon dioxide and allowing methane to escape into the atmosphere has significant global warming implications. 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 the waste in the landfill and the landfill design, but typically it has high organic carbon content, high concentrations of nitrogen and is usually slightly acidic. Landfills are designed and operate to seal the waste as much as possible from the surrounding environment. Central to this environmental protection is avoiding groundwater contamination. Recycle The more rubbish, waste and junk that gets recycled is the less that has to go to landfill. This in turn means less methane is released, causing less global warming, and less leachate seeping into the earth and damaging our already fragile eco system. |