How can we solve the problem of end-of-life tyres?

End-of-life tyres (ELT) are a global problem making up around 2 to 3% of all waste materials collected worldwide. CEO at the sustainability brand, Contec, Krzysztof Wróblewski, explains the damage they can cause to the environment and explores how we can solve the problem of ELTs.

It’s estimated that, globally, between 1 and 1.8 billion end-of-life tyres (ELTs) are disposed of each year, around 2 to 3% of all waste materials collected worldwide. The problem continues to accelerate as the global population grows and motorised vehicles become more readily accessible in developing countries. 

I believe the tyre waste problem needs to be addressed through circular solutions – “reuse” and “recycling” – that involve converting those ELTs into sustainable commodities.

Global waste problem in landfills

Consequently, one of the biggest problems we continue to see are tyres that simply end up in landfill. While that practice is banned in the EU, in the US, 16% of ELTs end up in landfills, according to a 2018 USTMA report. Not only do tyres take up a large amount of landfill space but there’s also a genuine concern over their environmental impact and the risks to human health.

Landfills filled with tyres are not a pleasant sight. Large piles of waste tyres attract disease-carrying rodents and insects because of the water that collects inside the tyres. As the tyres slowly decompose, they emit harmful chemicals into the atmosphere and soil, which affects the surrounding area. Recently, researchers discovered that a tyre chemical known as 6-PPD reacts with ground-level ozone to produce a 100 times more toxic compound.

Three major problems derived from ELTs

ELTs present several problems to human health and the environment.

Tyre incineration and harmful emissions

Another problem we should be aware of is the size and flammability of tyre materials. Large piles of discarded tyres often catch fire and create major environmental disasters.

One terrible example occurred in 1999: a lightning storm ignited seven million scrap tyres piled on the slopes of a canyon near Westley, California, according to Chemical & Engineering News (C&EN). A 60-metre fireball propelled smoke hundreds of metres into the air, sending soot as far as 100 kilometres away.

The blaze was only extinguished five weeks later. According to a subsequent investigation, the surrounding area was devastated by the spread of toxic emissions and the massive volumes of oil discharged from the heated rubber. A more recent example, the Kuwait fire, continues to burn to this day.

Burning tyres releases carcinogenic and mutagenic toxins into the atmosphere, which are known to cause cancer and genetic mutations respectively. Among the toxins emitted are cyanide, carbon monoxide, sulphur dioxide, and products of butadiene and styrene. 

Currently, incineration is an alternative solution to the waste problem caused by the disposal of ELTs, using advanced air emission control systems. However, inefficient or incomplete combustion also releases highly toxic compounds, including dioxins/furans, butadiene, styrene, and volatile organic compounds (VOCs). Heavy metals such as lead, mercury, and chromium VI are also released from incinerated tyres.

Unfortunately, the problem doesn’t stop there as tyres aren’t only made with rubber. They also contain fibre, textile, and steel cords to reinforce their structure, tensile strength, and durability. As with rubber, these materials aren’t easily broken down and will cause environmental harm if they’re not correctly disposed of and recycled.

Current tyre recycling environmental and health risks

There are many concerns over current tyre recycling solutions that are neither efficient nor safe. ELT waste disposal remains a critical environmental problem in many parts of the world and leads to severe air, water, and soil pollution issues. Despite being non-biodegradable, ELTs are still categorised as non-hazardous waste.

Unfortunately, poor management of ELTs is common in many developing economies, and globally, 75% of all ELTs are sent to landfills. In these locations, landfill disposal of whole and shredded tyres might be the most economical option. Nevertheless, it poses a genuine and major threat to the environment and public health. In the EU, ELTs sent to landfills have decreased from 50% in 1996 to only 4% today.

ELT disposal problem shifted to other countries

Dumping tyres in landfills has always been a sustainability problem. Over the last two decades, the EU has made enormous progress in solving the general problem of landfill waste. Since 1999, sending ELTs to landfills has been legally prohibited by the European Union, under Directive 1999/31/EC (EU. 1999).

However, it seems the problem hasn’t been comprehensively addressed but simply shifted elsewhere. If waste tyres aren’t being landfilled or incinerated in the EU, they’re being transported and disposed of in other parts of the world.

In the Middle East and North Africa (MENA), scrap tyres, along with other harmful materials, are often used to fire industrial ceramic kilns, according to EcoMENA, a regional think tank promoting green initiatives and fostering sustainable development.

In 2018, nearly half of the UK’s end-of-life tyres were exported to India to supply more than 55,000 cement kilns in the brick belt economy. The brick belt is an unofficial area covering parts of Pakistan, northern India, Nepal, and Bangladesh.

Both the UK and a number of importing countries want to see this trade, which is known for its unsafe working conditions and environmental pollution, stopped. 

EU directives towards improved waste disposal

Progress does continue to be made, I’m glad to say. In 2000, we saw the introduction of the End of Life Vehicles Directive 2000/53/EC. The document sets out measures for the “reuse, recycling, and other forms of recovery of end-of-life vehicles, and their components, which will reduce the disposal of waste”.

Also, the Waste Incineration Directive 2000/76/EC aims to “limit pollution by emissions into the air, soil, surface water, and groundwater, and the resulting risks to human health, from the incineration of waste”.

Currently, ELTs can be directly recycled via re-treading or turned into rubber-derived materials, with numerous applications in civil engineering. For example, some tyres are shredded to produce a ground surface for public thoroughfares and urban spaces.

It’s certainly a positive approach, but we need to develop more methods for sustainably recycling ELTs. Many more industries need to start considering their activities in response to the climate crisis and the urgent need for reducing CO2 emissions.

Pyrolysis – a sustainable alternative

Currently, more than one billion tyres reach the end of their useful life every single year. To meet CO2 emission goals set for 2050, I believe that implementing a circular economy across the tyre industry is essential. 

The integration of ELTs into a fully functioning circular economy would require tyre waste to be fully reprocessed into new materials. A process known as pyrolysis is increasingly recognised as the desirable and environmentally sustainable approach to solving the ELT problem. Pyrolysis technology has come a long way, and it’s now a safe and controlled process.

As byproducts, pyrolysis generates tyre pyrolysis oil (TPO), recovered Carbon Black (rCB), and recovered steel, which can be used to produce new tyre components and substrates. For tyre manufacturers, pyrolysis is the only effective and scalable solution to industry circularity.

Start now: address the global waste problem of ELTs

It’s reassuring to see major tyre manufacturers such as Continental, Michelin, and Bridgestone helping to lead the way forward in tyre lifecycle management. The manufacturing industry must now work together to reform current, unsafe tyre disposal and recycling methods to decarbonise supply chains and achieve emission reduction targets by 2050.

I believe pyrolysis technology is a crucial solution to the circular economy and can help the manufacturing industry move towards a more environmentally and economically sustainable future.

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