Now that the urgency of climate protection has been compounded by the urgency of the geopolitical impact, resource efficiency is the burning issue of our time. What is literally burning, however, is a large proportion of the 650,000 tonnes of used tyres that accumulate in Germany alone every year. While interest in the circular economy is slowly gaining momentum, Cologne-based bicycle tyre specialist Schwalbe has been working on a circular business model for years. In 2015, the brand introduced a tyre recycling process with 100% recyclability for inner tubes - today, every standard Schwalbe inner tube consists of 20% recycled rubber.
Compared to inner tubes, however, dismantling and recycling a tyre with all its different components is much more complex and time-consuming. In the 1990s, Schwalbe launched a downcycling process and turned the old tyres into rubber mats for the trade. The tyres were not incinerated, but a material cycle still seemed a long way off.
The drivers
This is why the brand regularly sought contact with the Technical University of Cologne. At its :metabolon Institute (on the site of a former landfill site), the university develops concepts for a sustainable circular economy. At the suggestion of his professor, Sebastian Bogdahn - himself a passionate cyclist - finally approached Schwalbe in 2019 in search of a cooperation partner for his master's thesis on bicycle tyre recycling. The pot finds its lid.
In his work, Bogdahn developed a holistic process chain - in theory. "But our goal and aspiration was always to realise it. What you work out in the lab and sketch out on paper doesn't necessarily have to work in practice. But it quickly became clear that the chances of success were there - and, above all, that everyone involved had the will and ambition to make it work."
The intensive collaboration resulted in the 34-year-old now being permanently employed by Schwalbe. As Recycling Manager, he is part of the four-person Corporate Social Responsibility team, which is led by Schwalbe's founding grandson Felix Jahn. In 2022, Schwalbe actually became the first bicycle tyre manufacturer in the world to launch a recycling system for tyres.
The converters
In addition to the TH Köln, Pyrum Innovations is one of the key players in the process. The Saarland-based company has a start-up story straight out of a picture book. In 2007, four friends decided to set up a company in a 9 m2 garden shed in Dillingen that would thermally break down rubber and plastic waste using pyrolysis: a process that works without oxygen. This means there is no combustion and therefore no emissions or odours. Several people had tried this before, but no one had yet succeeded. The Saarlanders were successful with their patented process.
"When I approached them three and a half years ago, they were still in an advanced start-up phase," says Bogdahn. Pyrum has been listed on the stock exchange for just over a year, and CEO and co-founder Pascal Klein is listed as a "Top 40 under 40" by Capital magazine in 2022. In the plants developed and built by Pyrum, the used tyres are first shredded and sorted into three components: steel, textile fibres and rubber granulate. The latter breaks down into steam and coke in the pyrolysis process. The vapour condenses into high-quality oil, which is purchased by BASF and used as a substitute for crude oil - for example in Vaude jackets or Mercedes door handles. The gas produced in the process feeds the plant, which is therefore completely energy self-sufficient. And the soot obtained, known in technical jargon as Recovered Carbon Black (rCB), is used by Schwalbe in the production of new tyres.
The collectors
However, the logistical implementation of the cycle also presented Schwalbe with challenges. A take-back system had to be developed that would bring the used tyres from specialist retailers to Pyrum and also get the dealers on board. At the start of the project in mid-2022, there were 50 bike shops - by the beginning of 2023, there were already over 1,300. Incidentally, tyres of any brand can be handed in. One retailer from Freising holds the tyre return record - and will probably continue to do so for many years to come: Ingo Ruhland refused to dispose of old tyres for over 23 years. Instead, he stacked them in the vault of his bike shop, a former beer cellar. At some point, he was convinced, they could be returned to a tyre recycling process. 20,000 collected tyres later, in November 2022, he and his team of five heaved the tyres into a lorry.
"We should be doing more in all areas to recycle such material instead of always mining new raw materials," he said during the collection. In future, returned tyres will no longer end up in the cellar at Radl Ruhland, but in the specially manufactured Schwalbe recycling box. Once it is filled with 200 tyres, it will be collected by logistics partner Emons. The Cologne-based company was also confronted with completely new challenges. "The exciting thing about this project was and is the unknown volume," says Emons branch manager Jan Hochlenert-Pottberg. "Nobody could say exactly what to expect during the initial discussions. But thanks to the early contact, we were able to play a key role in the logistics process, which very quickly resulted in an exceptionally trusting collaboration. Now we can sometimes even collect the filled boxes at the same time as delivering bikes to the dealer."
From master's students to tyre manufacturers, from the garden shed to the beer cellar... the cycle established by Schwalbe shows how wheels can interlock and make things happen if there is the will and commitment to the subject.
Interview with Pascal Klein, CEO of Pyrum Innovations
MYBIKE: Mr Klein, the bicycle industry is relatively marginal - why does it still play an important role for Pyrum Innovations?
Because it's a very nice market with which you can reach a lot of people. It's also a good way of demonstrating that it works and how it works. You wouldn't believe how many politicians, business leaders and decision-makers have contacted us because they are cyclists and first heard about us in a bike shop. This has opened an incredible number of doors for us. On a "small scale", we were able to show that it really is possible to close the circular loop.
You also work on the pyrolysis of mattresses, house insulation, carbon fibre products, etc. Why did you start with used tyres?
Because we really can bring about a massive improvement in the used tyre market in the short term and become completely "green". Currently, around half of the approx. 650,000 tonnes of used tyres produced in Germany every year are incinerated in cement works. This does not even include bicycle tyres. It can be assumed that almost 100 per cent of them are incinerated, as they are almost exclusively disposed of in the residual waste bin.
What actually happens to the steel?
The melted steel is turned into wire for new tyres. Here we have one hundred per cent recycling.
Apart from researching and implementing the process, what were the biggest challenges for you?
The technology is very complicated, and a number of companies have already burnt their fingers and miscalculated in the development of an efficient pyrolysis system. So there was always the prejudice: "Well, if large corporations couldn't do it, why should a couple of young guys from the Saarland be able to do it?" We were always on our own and were only taken seriously when BASF invested in us. Now people suddenly believe in us.
What are Pyrum's goals?
The long-term plan is to build up to 20 plants in Europe and thus recycle 15-20 per cent of the used tyre market in Europe.
Politicians and business leaders have learnt about us in the bike shop.
Schwalbe's tyre recycling system - the process
- The used tyres are shredded and separated in four stages. 1 tonne of used tyres yields 150 kg of steel, 100 kg of textile fibres and 750 kg of rubber granulate.
- The rubber granulate ends up in the pyrolysis oven at 700° in the absence of oxygen. This produces 190 kg of process gas, 250 kg of pyrolysis oil and 310 kg of pyrolysis coke (recovered carbon black, rCB).
- The pyrolysis plant is operated energy self-sufficiently with the gas.
- The oil is used as a crude oil substitute and is purchased by BASF.
- The rCB is used for the production of new tyres.
Interview with Sebastian Bogdahn, Recycling & Sustainability Manager at Schwalbe
MYBIKE: Sebastian, Schwalbe is the first bicycle tyre manufacturer in the world with a tyre recycling system. What does it look like outside the industry?
Our project has now become a model and is actually being cited as a blueprint for the circular economy in the tyre and rubber industry. It makes us proud that we, as a small medium-sized company, have managed to establish a flagship project within two or three years that now serves as a guide.
The challenge also lies in achieving a quality of recycled carbon black that can be used to produce long-lasting, high-performance tyres. What are the challenges here?
Tyre compounds are obtained from virgin carbon black, a black, carbon-rich mixture of crude oil and gas. The characteristics of the carbon blacks are very precisely defined - and this is not the case with Recovered Carbon Black. Different tyres from different brands are processed, and there is a corresponding variance in quality. We are now researching how to achieve as consistent an output as possible. Then we can adjust the rubber compound. This requires analyses, checks and a lot of fine-tuning.
The first Schwalbe tyre made from 100 percent rCB will be launched in 2023. What are your goals?
In the short term, the aim is to further optimise the processes and then, once everything is running smoothly, to roll out the programme in other countries. To do this, we need to clarify both legal and logistical issues. And, of course, our aim is to equip as wide a range of our tyres as possible with rCB - without compromising on quality and durability.
Specialist dealers pay 139 euros per collected box with 200 tyres. Has the financing model also been criticised?
I had actually expected this, but it was almost never the case. It was clear that such a process would have to pay for itself - we don't earn anything from it. And the disposal of tyres always costs something. Some dealers also demand a small contribution from their customers when they return tyres. There doesn't seem to be any criticism here either. I think this is also due to the fact that cyclists are generally sensitive and aware of the issue.
Tyre recycling: the benefits
- Avoiding waste and CO2 emissions during incineration
- Gaining crude oil substitutes in energy self-sufficient production
- Profit from Recovered Carbon Black for new tyres
- Reduction of CO2 and fossil raw materials in the manufacturing process
