Prof. Dr. Andreas Fath (left) and Michel Mues also want to use a playful approach to educate people about the topic.
Research project at Furtwangen University investigates the recycling of artificial turf
There are over 6,000 artificial turf pitches in Germany. If you were to lay them all side by side, they would cover an area 1.5 times the size of Frankfurt Airport. Artificial turf offers a number of advantages over natural grass: for example, it does not need to be watered or mown and can be used all year round. “However, artificial turf pitches also have disadvantages; for example, they rank fifth among the largest sources of microplastics. This is mainly due to the three tonnes of plastic granules used per pitch. Every year, a whole tonne of granules is blown away by the wind, or sticks to the soles of shoes as they leave the pitch, ending up in the natural environment,” explains Prof. Dr Andreas Fath from Furtwangen University (HFU).
Prof. Dr Andreas Fath and Michel Mues are part of a project team working on the “Re-integration of heavily weathered waste plastics into the circular economy” (RewitAl). For RewitAl, scientists from HFU have joined forces with researchers from the Universities of Aalen and Pforzheim. “Each university is exploring a different potential recycling approach, and we are in close contact with one another. HFU is contributing its expertise in the chemical approach,” reports Fath.
Not only does the infill on the pitches need to be topped up regularly whilst they are in use, but once their 12- to 15-year ‘playing life’ has come to an end, they also become a real problem when it comes to recycling. “Artificial turf consists of five to six different plastics for the fibres, infill and backing, which are very difficult to separate from one another. That is why artificial turf is often simply thermally recycled – in other words, incinerated,” says Michel Mues. Mues studied Applied Biology at the HFU and went on to complete a Master’s degree in Sustainable Bioprocess Engineering before joining the project.
“Our first major work package was analysing the constituents of the plastics used. In the granules made from end-of-life tyres, for example, we still found soot from the roads,” recalls Mues. “This work package has now been completed,” says Prof. Fath happily.
“I’m working on the functionalisation of plastics. That means I’m trying to chemically modify plastics in such a way that they develop useful properties,” explains Mues. He started by working with granules made from old car tires — or, in chemical terms, “styrene-butadiene rubber” (SBR). “We had the idea that this might be used to make a good absorbent because it contains styrene, which we’ve already used to achieve good results in other projects. Plus, the granules already have a large surface area, so they offer plenty of space for substances to bind to,” Fath summarises. Mues adds, “Depending on the surface structure and base material, different substances can bind to an absorbent. For example, microplastics or heavy metals can be filtered out of the water — similar to how a magnet works.”
“In the first step of transforming the turf granules into an absorbent, the granules are boiled in a mixture of sulfuric acid and hydrogen peroxide. This process not only chemically alters them but also cleanses them at the same time. By adjusting factors such as temperature and duration, we can influence the absorber’s subsequent properties,” Michel Mues explains the process. “Copper dissolved in water is visible as a bluish discoloration. After adding the absorber, the liquid has lost its colour again. “This is simple proof that the functionalisation was successful, because the copper in the water has deposited on the absorber. That was a major initial success,” says Mues. Next, the project team will examine other components of the artificial turf, likely the fibers. “We hope to find a chemical process that will allow us to give the fibers a new lease on life as well,” reports Mues.
“Together with the other universities, the project is examining the entire process — from dismantling the turf to recycling options for the individual plastics — whether chemical, thermal, or mechanical — all the way to the economic viability of these methods and possible alternative materials for future turf,” summarises Michel Mues. “Together, we want to give old artificial turf a new lease on life.”
The RewitAl collaboration project will continue to receive funding from the Baden-Württemberg Ministry of Science, Research, and the Arts through September 2027.
Internal link opens in the same window:More about the project
Further impressions
