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Landfills and Methane Gas – Any Upside?
Which is the lesser of the evils?
- landfill waste that biodegrades, or plastic;
- biodegradable waste in the landfill or even recyclables?
Read on to assess if biodegradable waste in landfills is even better than recycling.
About half of our waste lands in the landfill though the amount has been declining steadily since 2007 as a result of UK and European directives that urged an increase in recycling and other means of disposal. But because there still remain many types of materials that cannot be recycled or disposed of in any other way, landfill still remains an important part of disposal system.
Waste in the landfill does result in the production of biogas, especially when anaerobic bacteria decompose organic waste. The biogas comprises mainly methane and carbon dioxide. Methane is more potent as greenhouse gas than carbon dioxide as it is 28 to 36 times more effective at trapping heat in the atmosphere over a 100-year period.
All attempts should of course be made to reduce waste, reuse and recycle. But the reality is that we will end up with some waste and not all can be recycled.
Recycling has its own problems and of the waste that ends in the landfill, the lesser of the two evils is the one that biodegrades.
Obviously an impossible goal! Given the myriad of waste materials and their numerous chemical compositions, recycling has its own problems, some of which are:
- Recycling involves high usage of energy and resources and hence a net environment cost. Furthermore, many of the products that we think are ‘recycled’ are actually ‘downcycled’. For example a plastic milk carton can never be recycled into another carton but made into a lower-quality item like plastic lumber, which can’t be recycled again!
- Less than 10% of recyclables plastic containers get to the recycling facility as this is dependent on customers’ behaviour patterns. They need to end in the right bin and not the garbage bag on the way to the landfill!
- Even if they do get to the recycling facility success of recycling depends on the facilities capability. Recyclable paper food containers can pose a challenge to the facility because of their polyethylene coating.
Landfills are plagued by bigger problems than biogas production.
Waste that does not decompose – namely the infamous plastic and petroleum- packaging materials that can remain in the landfill for 100’s of years. They never fully biodegrade and persist as litter breaking up into pieces and find their way into our waterways and the ocean. They harm marine life both mechanically and chemically – choking and clogging their digestive systems and when these plastic feeding fish find their way to our dinner table, they harm us too.
Modern Landfills and Biodegradable waste
Landfills are nowadays constructed and operated to stricter standards in order to reduce adverse environmental effects. The amount of waste, especially hazardous waste is reduced and all efforts are made to recover value from the waste.
In some modern landfills, the conditions (water, humidity, temperature, and lighting) are optimally tuned to bring about a speedy biodegradation.
Element 100% biodegradable tableware will biodegrade under the right environment within 120 days, producing a non-toxic humus waste that can be used as fertilizers.
Methane emissions – the upside
In some landfills, the decomposition process will result in biogases, notably methane which is both hazardous as well as valuable. The EU Landfill Directive requires all new landfill sites from 2002 to capture the methane produced.
A recent study by the Environmental Change Institute, University of Oxford has found that the largest factor in the mitigation of methane from landfill is through methane capture, rather than diversion or recycling, due to the quantities of waste already in landfill sites. For the past two decades, technology has made advancements in monitoring and measurement techniques, controlling the movement of the gas for safety and health reasons and most importantly for capturing the gas for use. Improved landfill caps on new landfill sites resulted in a 61% reduction in methane emissions from landfill between 1990 and 2002. In addition, systems have been developed not only to control, but also to capture, landfill gas, involving the use of a network of pipes, wells, fans and/or vacuums to provide a favourable migration route to a common end point. Once collected, the gas is either disposed of by flaring or recovered for its energy value. The energy recovered is classified as a renewable energy source under the Renewables Obligation and so any electricity generated is eligible for ROCs.
In fact, about 40% of Britain’s methane emissions come from landfill sites and with careful management, UK’s electricity supply is increasingly coming from these recovered biogases (source: https://www.businesswaste.co.uk/facts-about-landfill/)
Methane gas recovery and electricity generation plant at a landfill site in Godmanchester, Cambridgeshire, England