From the production of textiles to their use and disposal - in the effort to sustainably reduce the output of textile microplastics it's important to identify and exploit potential savings and optimisation at all stages of the product life cycle. This was the key finding of the conference "Textile Microplastics - Solutions by Industry and Research" held on November 7, 2019 in Berlin, organised by the TextileMission project partners and sponsored by the Federal Ministry of Education and Research (BMBF). The partners presented first results of their research activities and discussed promising solutions together with around 90 participants.
Key topics were:
- Causes and extent of microplastic loss in textiles
- Development of low-emission textiles
- Biodegradable plastics as alternative fibre materials
- Textile recycling and circular economy
- Retention of textile microplastics in wastewater treatment plant
Focus on the entire life cycle of garments
"Studies have shown that 20 to 35 percent of the microplastics found in the oceans worldwide originate from garments made of synthetic fibres. The fibre fragments can cause inflammations and entanglements in the digestive tract of marine organisms. They influence natural behaviour, reduce fertility and can lead to the death of marine animals," said Caroline Kraas, project manager microplastics at WWF Germany, one of the project partners. She explained the extent of the problem and gave advices on how to find a solution:
"From a sustainability perspective, it is important to extent the research and action framework as far as possible. It is not just a question of particle discharge caused by the household washing of synthetic textiles. There are already considerable emissions at the textile production stage, another source of particles is the abrasion that occurs during wearing, and finally fibres are also released during the transport and when textiles end up in landfills. Avoidance must start at the very beginning and go on throughout the cycle".
The presentation of Caroline Kraas can be found here.
Strongest microplastic release during the first three washes
What are the causes of microplastic emissions from textiles? What influence does the washing behaviour of consumers have? What textile technology approaches can be used to develop low-emission textiles? The project partners Dr. Jens Meyer and Malin Obermann, scientific co-workers of the Research Institute for Textiles and Clothing at Hochschule Niederrhein - University of Applied Sciences, provided answers to these questions. Up to now, fleece products have been the focus of their investigations - a focus that needs to be expanded, as Jens Meyer explained: "Fleece products were previously regarded as particularly microplastic-emitting due to the deliberate destruction of fibres during the shearing and roughening process in production. To a large extent, this is also true. However, in our washing and drying tests, conventional filament goods such as pullovers and T-shirts made of polyester show sometimes a similarly high particle output".
A further test result catches the eye: during the first three washing cycles of a new garment by far the most microparticles are released. "This indicates that there are often still loose fibre fragments from production in the product that are only discharged during household washing," says Jens Meyer. A solution that all TextileMission partners consider worth testing could be a processing step (e.g. prewashing or pre-drying) directly connected to the production process. Pre-drying would have several advantages: The resulting fibre fragments are generally easier to filter from air than from water. In addition, the haptics and volume of the new garments, which are important for sales, would be less affected than in the case of laundry.
Advice for consumers: Always pack the washing machine as full as possible
Should it prove practicable, this approach would take effect at the beginning of the product life cycle. Consumers, on the other hand, wonder what contribution they can make during the use phase. "One recommendation is to always fill the washing machine as much as possible. Textiles being washed at a low load are exposed to higher mechanical stress and therefore release more microplastic," explained Jens Meyer.
However, the textile researchers are sceptical about the use of a washing bag on the market that promises to filter out most of the textile microplastic. "Although the protection of the textile by the surrounding wash bag has certain positive effects, we were unable to prove the announced filter performance in our tests," says Meyer. In addition, the bag reduces the washing performance.
Product development: machine parameters and alternative joining techniques as levers
The Niederrhein University of Applied Sciences is researching not only into the causes of microplastic loss, but also into the development of sports and outdoor textiles, which have a lower microplastic by design. Malin Obermann explained two approaches at different stages of the textile production chain. "Already during the knitting process in the production phase there is a high generation of microplastic load.. Initial tests with our institute's own large-scale circular knitting machine have shown that even changing two machine parameters can lead to a significant reduction in particle emissions," said Obermann.
Later, when the raw material is joined to fleece jackets and pullovers by the manufacturers, there are also promising levers. "Conventional seams increase the emission potential. Alternative joining techniques such as ultrasonic welding, which we have already tested, can lead to a reduction in this output", Obermann added. It remains to be proven, however, whether garments produced in this way also have the same performance properties as standard products on the market. In the further course of the project, the textile researchers, together with the participating industrial partners such as VAUDE, will also test biodegradable fibre materials and work on the implementation of the solution approaches in the textile supply chain.
The presentation of Hochschule Niederrhein can be found here.
Biodegradability of fibre materials in sewage treatment plants: viscose performs well
The extent to which materials declared as biodegradable are actually degraded in a sewage treatment plant within the framework of TextileMission is a research focus of TU Dresden. Prof. Dr. Stefan Stolte, head of the Institute for Water Chemistry, explained the first results achieved by laboratory sewage treatment plants and the OxyTop test system to the participants: "Within our test period of 58 days, pure polyester was, as expected, almost not degraded at all, while cellulose fibres such as viscose were almost completely degraded. It was found that dyestuffs, which in this case accounted for about 0.2 - 0.4 weight percent of the viscose fiber, had no negative effect on the biodegradability of the material."
A possible toxicity of the usually not degradable dye, however, remains unaffected by this finding. Stefan Stolte also warned against a prematurely optimistic generalization of the results: "These statements on biodegradability refer to the system sewage treatment plant - the degradation behavior for example in the deep sea runs under completely different conditions". Water temperature and pressure are just two examples.
The presentation of Prof. Dr. Stefan Stolte can be found here.
Further lectures were given by the following top-class speakers:
- Prof. Dr. Gunnar Seide (Aachen Maastricht Institute for Biobased Materials) on the biodegradability of plastics,
- Prof. Dr. Hans-Josef Endres (Leibniz Universität Hannover) on end-of-life options and sustainability aspects of bio-based fibre raw materials,
- Jérome Pero (Federation of the European Sporting Goods Industry) on European policy aspects of textile recycling,
- Carsten Eichert (Rittec Umweltsysteme) on technical aspects of textile recycling and environmental services,
- Nathan Obermaier (UBA - Federal Environment Agency) on regulatory aspects of microplastics.