What is a landfill? Why do we need landfills?
Any waste that is not recycled or reused has to go somewhere, and it usually ends up at a landfill site. Landfill sites can be created from a void made by quarrying or may form part of a land reclamation scheme.
Landfill sites exist all over the UK, and all over the world. Some sites practice ‘landraising’ (piling the rubbish directly on the ground), and some practice ‘landfilling’ (filling a hole in the ground with the rubbish). The rubbish in these piles is a mixture of household and commercial waste.
It is a fact of life that humans produce waste, that cannot be changed. Waste is cumbersome issue that civilisation has to deal with. The average household in the UK produces more than a tonne of waste every year. Add this up, and it equates to a total of 31 million tonnes per year, which is equivalent to the weight of three and a half million double-decker buses, a queue of which would go around the world two and a half times.
Landfill sites contain both household and commercial rubbish. Household waste that gets sent to landfill consists of mostly organic waste, for example food, paper, cardboard or wood. Other household rubbish contains plastic or tin packaging.
A lot of our individual rubbish is known as Municipal Solid Waste (MSW). World Bank defines MSW as: “Waste that includes non-hazardous waste generated in households, commercial and business establishments, institutions, and non-hazardous industrial process wastes, agricultural wastes and sewage sludge. Specific definitions vary across jurisdictions.”
A lot of the rubbish put in landfill sites today is from construction and commercial businesses, such as soil, concrete and brick rubble. This is known as inert waste because it is unlikely to react with other rubbish, making it relatively safe for landfill. and the commercial waste is mainly inert rubbish such as rubble, bricks, soil, and concrete. The inert waste is often used to build roads onsite, and then to cover the site over when it is full. Once the site has been covered and has been made ‘safe’, the area can then be repurposed, but there are heavy restrictions in place regarding this.
Landfills are located, designed, operated and monitored to ensure compliance with regulations. They are also designed to protect the environment from contaminants, which may be present in the waste stream. Landfills cannot be built in ‘environmentally-sensitive’ areas, and they are placed using on-site environmental monitoring systems. These monitoring systems check for any sign of groundwater contamination and for landfill gas.
What happens when a landfill reaches capacity?
When a landfill reaches full capacity, it is limited, and rehabilitated, to be turned into green spaces such as parks and community grounds. These will be maintained for up to 30 years after capping.
Depending on waste type and volume, landfills take many years to reach maximum capacity. Then a landfill is capped with a final layer of cover material, clay and vegetation. This cap layer forms a barrier, keeping odours in and rainwater out. The site is planted to suit its future use when it will be restored for recreation or light cultivation.
Why are landfills bad for the environment?
Landfill sites are ugly. And it’s not just the eye sore of increasing piles of waste that’s the problem, landfills are a major source of pollution, and there are many negative issues associated with them. Rubbish buried in landfill breaks down at a very slow rate and remains a problem for future generations.
The three main problems with landfill are toxins, leachate and greenhouse gases. Organic waste produces bacteria which break the rubbish down. The decaying rubbish produces weak acidic chemicals which combine with liquids in the waste to form leachate and landfill gas.
There are some secondary side effects as well: nauseous odors, unpleasant views, rat and seagull infestations, which create their own waste problems.
Many materials that end up as waste contain toxic substances. Electronic waste is an example. Waste such as televisions, computers and other electronic appliances contain a long list of hazardous substances, including mercury, arsenic, cadmium, PVC, solvents, acids and lead. Over time, these toxins leach into our soil and groundwater, and become environmental hazards for years.
Leachate is the liquid formed when waste breaks down in the landfill and water filters through that waste. This liquid is highly toxic and can pollute land, ground water and water ways.
Landfill contains vast quantities of substances that are harmful to the environment. Plastics such as PVC and other materials leach toxic chemicals as they break down.
E-waste is the fastest growing waste segment in the developed world. Even though it’s the most toxic everyday waste stream of all, most of it ends up in landfill. Electronic waste is loaded with heavy metals, solvents, and acids.
It takes a year or more to fill each landfill cell, during which time the contents are naturally exposed to rainfall. Rainwater filtering through the landfill dissolves and flushes 5-7 percent of the toxins with it to create a foul smelling liquor, known as leachate, which contains ammonia and various toxic salts.
Depending on rainfall, a single landfill site can easily produce several Olympic sized swimming pools of leachate each year. Leachate is carefully collected and recirculated into the landfill cells to prevent contamination of land, groundwater and waterways. Some leachate is reabsorbed when passed back into landfill, but the rest filters through again, picking up more toxins with each pass.
Greenhouse gas production is perhaps the biggest environmental threat posed by landfills.
When organic material such as food scraps and green waste is put in landfill, it is generally compacted down and covered. This removes the oxygen and causes it to break down in an anaerobic process. Eventually this releases methane, a greenhouse gas that is about 25 times more potent than carbon dioxide. Landfill gas comprises 35-55% methane and 30-44% carbon dioxide. Methane is also a flammable gas that can become dangerous if allowed to build up in concentration. The implications for global warming and climate change are enormous. Composting your food scraps and green waste in a compost bin can eliminate many of these problems.
Within the first 20 years of emission, methane’s greenhouse effect is far worse—somewhere between 84 and 100 times more potent than carbon dioxide. And when it comes to moving the needle on greenhouse gas emissions, what really counts is what happens over the next 10 – 20 years.
So how much methane is produced by a typical landfill site? A huge amount. In fact, enough to fuel a power station.
For example, a landfill that serves a population of half a million, generates nearly 1.7 million cubic metres of methane each month. Usually 85% of this gas is captured and fires a generator which provides electricity to about 10,000 homes. While plant operators and governments often choose to describe landfill gas power as renewable energy generation, it’s certainly not a sustainable, or environmentally friendly form of generation. When burned, methane produces carbon dioxide – just like oil and coal.
Landfills are the earliest form of waste management, however in the modern day we have come to realise that these sites aren’t good for our planet. Some of the reasons include:
- Landfill is expensive for taxpayers
- High levels of methane gas and CO2 are generated by the rotting rubbish in the ground. These are greenhouse gases, which contribute greatly to the process of global warming.
- Toxic substances end up in landfills, which leech into the earth and groundwater over time. This creates a huge environmental hazard. Substances include: arsenic, mercury, PVC, acids, lead, and home cleaning chemicals. Leachate – the toxic liquid formed when water filters through landfill waste – can easily contaminate our waterways.
- Landfills present a fire risk due to the gases they create. Methane is the main gas created, and it is also highly combustible. If a fire does occur, firefighters will often use a fire-retardant foam instead of water to fight the fire, due to the fact they don’t know what chemicals they are dealing with – further adding to the chemical footprint of the landfill site.
- Landfills trap waste underground with little oxygen, and so even waste that would usually decompose quickly, such as fruit and vegetables, will take a long time to do so in landfill. Some materials in landfill will take over a million years to break down! Throughout this time, the landfill will be releasing undesirable and dangerous gases, meaning the area will have to be managed forever to ensure there is no excessive pollution or urgent issues.
Why are landfills necessary?
Landfill meets a critical infrastructure need – to deal with the residual waste produced by businesses and households. This waste is expected to grow as the population increases, and with current consumer behaviours.
Even with improved recycling rates, there is still general waste (anything that cannot be recycled) to be managed safely and effectively.
How can we send less to landfills? What is the solution to landfills?
At some level, most of us agree we should try to avoid, or at least reduce rubbish that we send to landfills. The word landfill conjures up images of vast, foul smelling open tips, strewn with garbage, teeming with scavenger birds and flies. Let alone the pollution, and problems to wildlife and nature that come with landfills, which is becoming a more talked about subject.
You may have heard of the term ‘zero waste’. Learn more on this here. Living a zero-waste lifestyle means you strive to use as little single-use plastic as possible, instead opting for sustainable and reusable alternatives. In short, it means you send as little as possible to landfills. Replacing as much as possible with reusable products includes everything from food and drink packaging, to hygiene products, to clothing, either more sustainable or plastic free, which will help protect the environment, benefit communities and support a circular economy. The 3 R’s play an important role in this; Reduce, Reuse, Recycle. This means reducing what you ‘use’ where possible, reusing as much as you can, send whats left to recycling, and compost what you cannot, then finally the small part of waste left goes to landfill. It’s about making a conscious effort to make better choices.
At Unisan, we love helping workplaces dramatically increase their recycling rates and manage waste better, in order to send less waste to landfill and become more sustainable. Setting up an effective recycling station can make all the difference.
Some points to help you recycle better at work:
- Clear labelling/signage – make your bin station ‘fool-proof’ by communicating in a crystal clear way what can go in each bin. Then anyone who uses the bin can tell at a glance where to put their waste.
- Make sure there’s enough of them – make sure that it’s just as easy for your staff to correctly recycle waste as it is to just put it in general waste.
- Remove personal bins – having bins under every desk makes it too tempting to just put all waste in one bin. Remember, the goal is to make recycling as easy as single-stream waste disposal; which may have to mean making it harder not to recycle!
- Run a waste awareness day/programme. The key to ensuring staff know what they can recycle is to enable them to fully understand the process; don’t just tell them what, tell them why. Some waste management companies today will actually run an event at your workplace, giving staff in insight into the process behind their waste management
“the people who make the biggest difference are the ones who do the littlest things constantly”
We’re enthusiastic about making recycling at work easier and more engaging. We believe this enables people to do the right thing and allow companies to demonstrate their commitment to sustainability and the environment. Find out more here on how we help transform companies environmental commitments for the better, or call us on 0300 700 6000 for expert advice on how your business can move further towards zero waste!
We have a fantastic range of recycling and waste bins, whether for offices, schools, universities, reception areas, break out or canteen areas, or even for back of house, such as warehouses and distribution areas. Click here to see our range.
We also offer bespoke solutions, which focus on design, so that they’re not only highly effective and suit your waste & recycling needs, but they look great in your workplace. Click here for inspiration.
In theory, providing there are no earthquakes, or underground methane gas explosions, landfill sites that are well constructed and managed may be able to contain toxic chemical and leachate byproducts for hundreds of years. But the vast quantities of landfill gasses from landfills cannot be so contained.
Before any methane is burned, landfills produce almost as much raw carbon dioxide as methane. And after taking into account burned off methane, a typical landfill site produces thousands of tonnes of carbon dioxide per month.
In striving to make our organisations and waste management more sustainable, we should be doing everything in our power to eliminate landfill waste.
A detailed look at landfill sites
A) To prepare the land before waste is deposited, several layers of linings are installed to seal up the base. Before beginning to deposit waste, this process has to be verified independently for quality assurance. The process is:
1. A regulating layer is laid down to smooth out the surface.
2. A layer of clay is then put down to provide an impermeable material to help prevent liquid from escaping.
3. The third layer is a plastic liner
4. Geotextile is then placed over the plastic.
5. A fifth layer of gravel is then installed.
6. A layer of geotextile is the last stage of preparing the base.
B) All waste from the local area (e.g your general waste bin), is brought to the site and tipped into the specially created cells. A compactor rolls over the waste to squash it and fill the space efficiently, to create a level surface.
C) Each cell is built up with waste stage by stage. At the end of each stage, it is covered with inert soils or a special matting that helps to prevent odours and keeps the waste in place until more waste can be placed on top to complete the cell.
D) Gas extraction wells are inserted into the cell to allow the gases that are created as the waste breaks down to be captured to generate electricity.
E) The gases are pumped to a turbine house where they generate electricity for the National Grid.
F) When water falls onto site it runs through the waste and collects solids and liquid. This liquid is called leachate. Leachate runs to the bottom of the cells where it is collected in a sump and pumped to storage tanks before it is taken off site to be treated before disposal
G) Each cell is filled with waste until it reaches a certain agreed level. Then the area is capped with a permanent plastic cover before we begin work to restore the land.
H) Restoration involves creating several layers above the waste to seal in what is below and protect what will grow above using a combination of high tech linings, subsoils and topsoils. The idea of this is to bring that land ‘back to normal’ to encourage nature and wildlife back to the area.
I) Monitoring bore holes are located on and off site to allow us to ensure the quality of ground water in the vicinity of the site.
J) Surface water ponds can be found on the site. As surface water runs off the landfill site it is collected in the ponds to allow any soil particles that may have been collected in the process to settle before the water is allowed to discharge off site.
K) Around the perimeter of the site there is a de-odourising system installed along the fence. This helps to capture airborne odours and neutralize them before they leave the site.