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Get the knowledge: understanding the impacts of waste
We create mountains of waste every day. How do we get rid of it all? Where does it go? And why is our appetite for rubbish an increasing problem for other countries?
The world has a serious waste problem. According to The World Counts, globally, we create an average of 60 tonnes of household waste every single second, and the World Bank predicts global waste will increase by 70% by 2050, resulting in a total of 3.4 billion tonnes of waste generated every year. All this waste needs to go somewhere.
We can all play a significant role in keeping waste out of landfill and incineration facilities
A major contributor to this growing mountain is municipal solid waste, which is the rubbish produced by homes, businesses, schools and organisations within the community. And the huge assortment of materials thrown away under this category – plastics, metals, glass, paper and cardboard, food, electronics – adds to the problem.
Much of these materials can in theory be reused or recycled but factors such as infrastructural limitations, consumer behaviour and international policy means it is often cheaper and more convenient to simply write it off as waste, although this varies greatly by country. Read more about recycling and its challenges.
If not recycled or repurposed, waste will be disposed of in three main ways:
Landfill
A landfill site, also known as a tip or dump, is probably the oldest form of waste disposal. It is essentially a large hole in the ground which is filled with waste, and when full, covered over. There are multiple environmental issues associated with landfill, including:
Contributing to climate change
When certain material, such as organic matter, breaks down it releases biogas (primarily a mixture of methane and carbon dioxide) into the atmosphere, which leads to global warming. According to the International Solid Waste Association (ISWA), landfill sites stand to account for 10% of the world’s greenhouse gas emissions by 2025.
Contaminating soil and water
Waste in landfills often contain toxic materials, including heavy materials such as lead and mercury, and toxic plastic additives, which can leach into soils and water near the site impacting plant and animal health.
Creating a hazardous environment
Methane produced by waste can cause explosions and fires, while the structure of landfill sites can cause devastating accidents. In March 2017, for example, the Addis Ababa landfill site in Ethiopia collapsed, killing an estimated 113 people.
Impacting wildlife
Bird populations are increasingly choosing to nest near landfill sites instead of heading south, because of the endless food supply they provide. As well as toxins in the waste harming the health of birds and their offspring, the change in migratory behaviour spells disaster, certainly in Europe, where food waste going to landfill is being significantly reduced.
Landfill sites in developed countries are built with a number of safety controls, including leachate collection, monitoring wells and vent pipes. Some have degassing methods to remove methane, and other noxious gases, which is an improvement over traditional landfill sites, but are not without problems.
Degassing is usually performed after a landfill site has been covered over, so a large proportion of methane will have already been released into the atmosphere. As research from the World Bank demonstrates, around 37% of global waste is disposed of in some kind of landfill site, only 8% of which are classed as ‘sanitary’ landfill sites with gas collection systems. Open dumping, meanwhile, is still prevalent, accounting for about 31% of waste.
Incineration
After landfill and open dumping, incineration is the next most popular form of global waste disposal. Here, waste is burned at high temperatures to convert it into ash, flue gas and heat, with the heat used to generate electric power. This is why incineration is sometimes called ‘waste to energy’.
Compared to landfill, incineration has some advantages. Incinerators don’t take up much space, they are less polluting of groundwater and air (if effluent and emissions control is used) and the creation of electricity as a by-product is certainly a benefit. But the drawbacks to incineration mean it remains a contentious method of waste disposal.
Firstly, the amount of electricity generated is minimal. According to the International Energy Agency (IEA), for example, in 2018 in the EU the overall energy production of all waste (including industrial waste as well as municipal solid waste) amounted to just 2.4% of the EU’s total energy supply.
Secondly, while modern incinerators have made progress in cutting their emissions, pollution still occurs. As more local authorities view incineration as a ‘greener choice’ compared to landfill, more incineration facilities are being constructed – even though they are extremely expensive – which will exacerbate this environmental impact.
The environmental NGO ClientEarth estimates that by 2035 incineration will be more carbon intensive than landfill, as well as an increasing source of toxic air pollution.
Finally, incinerators don’t get rid of waste entirely. The process will reduce the original volume of waste by around 90%, which is clearly a significant improvement on the space taken up by landfill, but the incinerated waste still needs to be disposed of, and it’s usually landfill.
Composting
Composting is only suitable for organic waste matter, but given the world’s increasing food waste problem, it represents a key method of waste disposal. According to the World Economic Forum, around 931 million tonnes of food goes to waste every year, responsible for up to 10% of global carbon emissions.
There are two main types of large-scale composting, many of which are used by local authorities in regions where household food waste collections are available.
In-vessel composting
This involves mixing food waste with garden waste, shredding it and then composting it in an enclosed system for around 2-4 weeks at temperatures of up to 70°C. This speeds up the composting process and ensures any harmful microbes are killed off. The material is then left outside to mature for a further one to three months with regular turning and quality checks before going on to be used as soil conditioner.
Anaerobic digestion
This process uses microorganisms to break down food waste, animal manure, slurries and energy crops in the absence of oxygen, inside an enclosed system. As it breaks down it gives off methane, which is collected and converted into biogas and used to generate electricity, heat or transport fuels. It also creates a nutrient-rich digestate that can be used as a fertiliser for agriculture and in land regeneration.
The main challenges of composting in either form is that it is a slow process which requires – on a commercial scale at least – high levels of investment in tanks and equipment. It can also be a rather pungent process, which makes finding suitable locations for large-scale facilities a challenge.
The global waste trade
Another method that countries rely on for getting rid of waste is to export it overseas, ostensibly for further treatment, disposal or recycling. Typically, waste is sent from developed countries to developing countries, in part to help reduce costs, and also to mitigate the lack of waste infrastructure in their own nations. Countries in the Global South tend also to have fewer regulations around waste, which is why they are major recipients of toxic and hazardous waste materials.
For a long time, this arrangement was seen as beneficial to developing countries, since it created an economic boost through the provision of jobs and value of recovered materials. But the environmental and social toll taken on these regions is significant. From communities living and dying in landfill sites, to the mismanagement of materials resulting in toxic waste fires, the global waste trade comes with a huge range of problems.
As a result, the amount of the UK’s low quality and hard-to-recycle plastic taken by China fell 94%, according to the BBC. Malaysia has also sent back thousands of tonnes of non-recyclable waste to countries including the US, UK, Canada and Australia, after the country’s environment minister Yeo Bee Yin said that it will not be "a dumping ground to the world".
Without the option to simply palm the waste problem off onto other nations, developing countries are now increasingly reliant on landfill and incineration.
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How to reduce waste
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What’s the best type of waste disposal?
Each of these methods of waste disposal come with their own disadvantages, but they do have something in common: none of them address the underlying problem of waste. The best-case scenario – as promoted by circular economy thinking – is to prevent waste from occurring in the first place, and then for waste that is unavoidable, to ensure it is reused or recycled.
As such, we can all play a significant role in keeping waste out of landfill and incineration facilities, just by being mindful of the waste we create and how we get rid of it.
Check it out
For more information on these issues:
- The World Counts data on household waste generation.
- International Solid Waste Association Roadmap for closing waste dumpsites.
- World Bank report on global waste.
- IEA data on EU energy production from renewables and waste.
- Groundwater contamination from a municipal landfill, Science of the Total Environment, October 2020.
- Birds diss migration, live on landfill, Movement Ecology, March 2016.
- Tolkic Consulting Energy from Waste 2019 report.
- ClientEarth report Greenhouse gas and air quality impacts of incineration and landfill, March 2021.
- World Economic Forum article Global Food Waste Solutions March 2021.
Media reports, including from The Independent on communities living and dying in landfill sites and the BBC on hard-to-recycle plastic taken by China and Malaysia, and NGO campaigns, including Greenpeace's on the mismanagement of materials.
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