Tell me more about landfill
People have been burying waste in the ground for hundreds of years. Today waste is still buried in the ground, often in old quarries that have finished operating and then been especially adapted to contain the waste in a safe way for many years to come. These holes in the ground are referred to as landfill sites. The following paragraphs explain how landfill sites operate, why they are used for disposing of north London's waste now, how much they cost and why we no longer want to use them as a method of disposing of north London's rubbish in the future.
What is a landfill site?
A landfill site is a hole in the ground, often an old quarry which is adapted to be used for burying waste. Typically the quarry sides will be smoothed and then the site will be engineered to ensure that none of the liquid, which is produced as the waste decomposes, leaks out into the surrounding ground. An operator of a landfill site has to gain planning permission from the local authority and a permit from the Environment Agency before it can start operating a landfill site. Once operational, incoming waste collection vehicles filled with rubbish are weighed at a weighbridge on arrival and their load is checked to make sure that it falls within the waste permitted to be managed at the site. Once the waste is accepted the waste collection vehicles drive to an area of the site where they unload their contents. After the waste is deposited, the waste is spread out and compacted. The waste is compacted so that the landfill is filled with as much waste as possible and also so that the landfill operator minimises the risks of site subsidence over time as the waste decays.
Some landfill sites are rail linked, so that the waste arrives by train in enclosed containers which are then transferred to lorries which transfer the containers to the areas of the landfill for the rubbish to be deposited.
Once a site is full, the rubbish is covered with a capping layer of material including soil and it can then be used for farmland, forestry or recreation such as a golf course.
Landfill sites are designed to protect the environment so the compacted waste is covered with soil or alternative materials at the end of each day to minimise odour and windblown litter. The liquid produced as the waste decomposes is collected and either treated onsite or offsite for example at a sewage treatment works.
A landfill site will also produce landfill gas, a mixture of carbon dioxide, methane and water vapour. Over a 100 year period methane is 25 times more potent as a greenhouse gas compared to carbon dioxide so it is important to control landfill gas. The gas will be collected through a network of pipes in the site and then burnt in an engine to produce electricity. Landfill sites will continue to produce gas long after they have ceased accepting waste.
Where does North London Waste Authority landfill waste and why?
In north London only 32% of the waste from households in the area is reused, recycled or composted. This leaves 78% that must be disposed in some way. North London Waste Authority can use the Energy from Waste facility at the Edmonton EcoPark to burn the remaining waste to generate electricity, but as that has a limited capacity we also need to dispose of waste elsewhere. Landfill sites provide a suitable alternative disposal outlet.
We currently dispose of waste from north London The majority of waste from north London which goes to landfill goes by train to a site in Buckinghamshire. Some waste goes by road to other at landfill sites in Cambridgeshire, Essex, Leicestershire and Northamptonshire.
What does it cost
Landfill sites charge a fee for every tonne of waste that is brought into the site plus the government's landfill tax. The costs for disposing of waste to landfill ranged from £80 to £121 per tonne including tax according to the Waste and Resources Action Programme in 2013 . However, that Waste and Resources Action Programme report was prepared when the landfill tax was £64 per tonne, and the tax has now risen to £80 per tonne so the total average costs are significantly higher. In addition to the cost of disposing of waste to landfill there is also the cost of transporting the waste to the landfill site.
Why we can't go on doing this
We want to move away from using landfill sites as a disposal solution for managing waste for a number of reasons:
1. As waste decomposes in landfill sites it generates landfill gas - a mixture of methane, carbon dioxide and water vapour. Methane is 28 times more powerful as a greenhouse gas than carbon dioxide over a 100 year period. Landfill sites also have the potential to create odour, windblown litter and traffic noise as the collection vehicles and compaction vehicles move around across the site. In addition, as the waste decomposes it produces a liquid which must also be collected for treatment. These impacts will be minimised by the way each landfill site is managed, but to discourage waste generation and encourage reduction in use of landfill, landfill tax was introduced. In recognition of the environmental impact of landfill, ‘active’ waste (household-like waste) which decays in landfill sites is taxed at a higher rate than ‘inactive’ waste (rubble, soils, etc) which won't decompose to create landfill gas or liquid for treatment.
2. landfill sites are running out, particularly in the south east of England. As we fill up the sites that do exist, there are not enough new sites being developed to replace them.
3. landfill sites are expensive to use. Most sites are remote from London so the transport costs are relatively high and in addition the landfill tax is an added incentive to move away from landfill disposal as soon as possible.
4. putting waste into a landfill means disposing of north London’s waste outside of the capital in someone else’s area. As evidence that some local authorities outside of London no longer want to accept north London’s waste and also anticipate the closure of out of London facilities, the South East Waste Planning Advisory Group objected to north London’s spatial plan for allocating land for waste use in north London. The South East Waste Planning Advisory Group argued that more treatment capacity for waste would be required and that additional capacity should be provided for within the Plan for new waste facilities. In their response to the draft North London Waste Plan for the area, the South East Waste Planning Advisory Group responded that:
“The NLWP should set out how and where all the waste arising within the plan area will be managed over the plan period. If facilities outside the NLWP area are to be used, the deliverability of these facilities should be confirmed. The "homeless" waste is currently being sent to facilities outside the plan area, several of which are scheduled to close within the next four years. The covert strategy in the Plan is not deliverable because the facilities currently managing a significant portion of waste arising in North London will not be available for the majority of the Plan period.”
(North London Waste Plan, Schedule of Representations, February 2012 - http://www.nlwp.net/documents/2012_examination.html)
5. The Mayor of London’s planning policies require London to become more self sufficient in terms of managing the waste that is created in the capital within the capital over time.
6. Putting waste in a landfill site means that the value of any natural resources contained within the waste is lost for good. However, if waste is recycled any metals for example can be extracted for further use and even if something is burnt any ferrous metal can be extracted from the incinerator ash and the energy produced can be used to generate electricity.
7. Waste that is separated for recycling can be sold to generate an income which can be used to offset some of the costs of the recycling collection and treatment. Sending waste to landfill is more costly.