What happens to … Old car tyres?
Every year, the Dutch car dismantling companies and garages collect some eight million tyres that have reached the end of their useful life. The resultant huge stack of tyres is subsequently very efficiently recycled. But exactly what form does the process take and what can be made from old car tyres?
The collection and processing of old tyres is well organised in the Netherlands. Importers and manufacturers of car tyres have joined forces in the Vereniging Band en Milieu (Association for Tyres and the Environment – BEM), which since 2004 has implemented the Besluit beheer autobanden (Car Tyres Management Decree – Bba). An efficient collection and recycling system has been created for this work, that operates under the name RecyBEM. The principle behind the system is as effective as it is simple: for every new tyre sold, certified collection companies take receipt of one old tyre. In this way, almost 100 percent of all end-of-life car tyres in the Netherlands are processed in an environmentally responsible manner.
One of the RecyBEM-certified collectors is the Amsterdam-based Granuband, a company that has been a serious player in the recycling of tyres for more than 25 years. A large proportion of the collected tyres are supplied by ARN-affiliated dismantling companies. As well as car tyres, the company also processes truck tyres, bicycle and motorcycle tyres and tractor tyres. The process starts with a screening stage to select tyres still suitable for reuse. “Following selection, around one quarter of all end-of-life tyres is given a second life, for example in Africa, where they can still be driven a considerable number of kilometres,” explained Maarten van Randeraat, director of Granuband.
For the remainder – each year the company processes some 3.5 million tyres – Granuband has set up a professional factory in Amsterdam. Here, the tyres are fed into a shredder, that grinds them into tiny pieces. The various raw materials are then separated in phases. As well as rubber, other materials such as steel and canvas are also used in tyres. “To better separate the steel wires present in the tyres from the rubber, we ourselves developed what is known as the Clean Wire System. This system increases the purity of the recycled steel, and saves several more percent of the rubber. We sell the steel to a client who uses it as reinforcing steel for concrete,” continued Van Randeraat. “Following separation the canvas is incinerated and the thermal energy is recovered. The separation process also produces a small quantity of minerals, from the sand that comes with the tyres. That fraction can for example be used in road building.”
Clearly, the lion’s share of a car tyre is rubber. The rubber material is ground at the Granuband factory into granules of different sizes. A large proportion of the granulate is used by Granuband itself for the production of rubber tiles. “We are the only tyre processor with its own production facility; all other tyre processors deliver their raw materials to the industry,” explained Maarten van Randeraat. “The rubber tiles we sell under the brand name Granuflex are for example sold to municipalities and DIY centres across Europe. We make them in a range of colours and they are used in playgrounds but also in animal sheds and on roofs. We also produce rubber mats for use in gyms, in our own plant.”
Artificial turf and noise insulation
Granuband sells on any residual granulate to other parties who convert it into a whole variety of products, ranging from brake blocks for cars and flexible adhesive through to the filler granules spread on artificial sports pitches. “To ensure the ideal playing conditions, sand and small rubber granules have to be washed into artificial turf. Rubber granulate is also often used as a filler layer beneath an artificial turf pitch. Together with the Gemeentelijk Vervoer Bedrijf (Municipal Transport Company GVB) and the Port of Amsterdam, we have completed a project to make tram rails quieter by installing profiles produced from our recycled rubber against the rails. The initial results of the trial are extremely positive and The Hague and Rotterdam are considering taking part in the future,” said Maarten van Randeraat.
As with regular car recycling, developments in and around the recycling of car tyres continue to take place. Granuband for example has developed a tile that can be used on rooftops as a water buffer, in response to the growing trend for the use of green roofs in urban environments. “The tile has a capacity of 15 litres per m2. By buffering rainwater in this way, the sewer system is relieved and humidity levels in cities are improved,” continued Maarten. “Another important development is the devulcanisation of recycled rubber. Researchers at the University of Twente have achieved huge advances in this process. In the future, it should be possible to process 50 percent of recycled rubber from the compound. The current maximum is just 5 percent. This promises to make a huge saving in raw material use.”
100 year lifecycle
If it is left to Maarten van Randeraat, recycling and the various possibilities of reuse will extend the total lifecycle of car tyres to a staggering 100 years. Even today, the recycling of old tyres is almost a closed circle. “Over the past few years, our sector has become more professionalised. We are increasingly succeeding in our efforts to extract and reuse the last remaining minerals and the textile fraction from tyres. Only a very small proportion of the car tyre – around 1 percent – is left for incineration, and even from that 1 percent we recover energy. A car tyre has a useful life of 3 to 5 years, before being reused on several occasions, in granulate form. The filler layer for an artificial turf pitch lasts between 8 and 12 years, and a rubber tile on a playground can be left in place for up to 20 years. Tiles that end up as water buffers on rooftops can have a useful life of 50 years. All together, you soon end up with a lifecycle of 100 years. It is hard to imagine a more sustainable product lifecycle.”