Ever wondered what happens to your car or van tires when the time comes to replace them? In many ways, it’s never been easier to buy replacement tires online, with companies like Avatyre providing a very straightforward means of choosing and ordering tires for almost any vehicle. However, as choosing your new tires becomes easier and cheaper, the conundrum of what to do with tires which have reached the end of their useful lives remains a significant problem for environmentalists.
The UK alone produces 55 million waste tires every year. With strict new EU legislation being recently introduced, the traditional option of sending life-expired tires to landfill is no longer available. In any case, sending tires for landfill had posed significant problems for some time. By their very nature, tires are largely unsuitable for disposal in this way. Their size and shape means that they take up a disproportionately large amount of space in landfill. Moreover, they can trap methane gasses, which can fill the well of the tire causing it to rise to the surface over time and, in some cases, damaging the lining material which protects the surrounding land and water table from contamination due to leaching from the landfill site.
The presence of zinc, heavy metals, and other chemicals used in the vulcanization process means that tires in landfill are quite an unwelcome proposition. The UK Government has shown itself to be committed to ensuring that tires are recycled properly and, as this Government document shows, it promises firm action against anyone involved in illegal disposal of tires.
Re-use or recycle?
Although extending the life of tire carcasses by replacing the tread pattern has fallen out of favor in recent years, there is still a booming export market for used tires. It’s estimated that at least 10% of the UK’s used tires are exported, mainly to Eastern Europe, South America and Africa for re-use. In many ways, this is an extremely green way of dealing with used tires. There is some concern, however, that unless the trade in used car tires is regulated, we may be merely exporting the problem to countries which do not have the legislation or facilities for the ultimate safe disposal of used tires when they finally reach the end of the road.
It is, of course, possible to make use of old car and van tires in more constructive and imaginative ways. Old tires have turned up as plant pots, garden benches, or even waste bins in municipal parks. While eye-catching, this sort of creative use for old tires is unlikely to make significant inroads into the numbers of waste tires generated each year by UK motorists.
For most life-expired tires, recycling is the most practical option. There are two principle means of recycling; shredding and combustion.
Shredding involves chopping up the tires using rotary cutting discs. The steel content is removed for conventional metal recycling. The rubber is further processed into small bead-like chunks. The resultant crumb-like texture has a variety of uses, from road making, paving material for play areas or sports grounds to moulded products such as gymnasium matting or park benches. Alternatively, the rubber content can undergo a process known as De-vulcanisation which effectively returns the rubber to its natural state by removing the bonding in the molecular structure. This ensures that the recycled rubber can be employed in a much wider range of uses – including new tires.
Tyre combustion in specialized incineration plant is probably the single most common fate for life-expired tires. The process, known as pyrolysis, involves heating shredded tires in a sealed, oxygen-free reactor vessel which drives off gasses for combustion, usually in a combined heat and power generator. Most of the remaining rubber breaks down into an oily liquid which can also be used as fuel. The small amount of remaining solids or “char” can be used as a low grade fuel or landfill. When carried out correctly, pyrolysis is a clean and almost waste free means of disposal.
So when you order your next set of tires online, you can be sure that, thanks to the ingenious ways in which your old tires are sent for disposal, the environment is being properly protected.