A special filter module for washing machines is being developed to reduce emissions of microplastic and synthetic microfibers into the environment. This is to be operated with virtually no pressure loss and manufactured from biodegradable polymers. The particularly innovative approach results from the adaptation of biological models.
Although the hazard potential of microplastics for humans and the environment cannot yet be fully assessed, there is already sufficient evidence that emissions must be drastically reduced. Fibers that end up in wastewater during washing are in 10th place among microplastic emissions in Germany with about 78 grams per capita and year (see Consortium study Microplastics). They thus make a not inconsiderable contribution to the pollution of the environment with plastics. FibrEX has set itself the goal of reducing microfiber emissions with the aid of a filter for washing machines. The filter concept should be transferable to applications in textile factories, industrial laundries, and for wastewater treatment plants.
During washing, microfibers mainly come loose from synthetic clothing due to abrasion and get into the wastewater when the washing machine is drained. The microfibers are not completely filtered out by wastewater treatment plants, so that they continue to flow into the waters with the sewage treatment plant effluent and can even be emitted into the air and soil via agriculturally applied sewage sludge. A technical process or product for the retention of microfibers, which are discharged from washing machines and industrial manufacturing processes into wastewater, is still lacking. Wastewater treatment plant operators are not currently experimenting with new filter technologies, but are focusing on optimizing washing and manufacturing processes to reduce the release of microfibers.
The development of the washing machine filter is very demanding as the filter itself should not lose any plastic particles during use and must be robust. It must also not cause any additional technical or financial effort and must be integrated into the existing washing machine system. As a result, both material and process engineering aspects are investigated. The focus lies on the use of bio-based polymers. The materials are tested in a test rig and the filter process optimized.
The filter concept is based on biological models. There are numerous organisms in nature that specialize in food in particle form, such as zooplankton and phytoplankton. They are grouped together as suspension eaters. They also include filter feeders such as mussels, crabs, and whales. They can serve as role models to optimize the structure, materials or function of the filter.
The project follows on from existing work by Fraunhofer UMSICHT, which has been dealing with microplastics since 2014. Following the studies on the current state of knowledge on microplastics and plastics in the environment, “fibrEX“ is now the first project to deal with a concrete solution to the microplastic problem. Project results are expected by the end of 2019.
Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT