Researchers Develop Innovative Filter to Combat Microplastics in Laundry Wastewater
Microplastics, tiny plastic particles prevalent in wastewater from washing machines, pose a significant threat to both humans and wildlife. In response, researchers at the University of Bonn have innovated a filter system inspired by fish gills, significantly reducing microplastic pollution. Early trials of this system have shown promising results, eliminating more than 99 percent of plastic fibers from washing machine wastewater, as detailed in the journal npj Emerging Contaminants.
It is estimated that a typical household of four can contribute up to 500 grams of microplastics annually due to the wear of textile fibers during washing. This makes laundry a substantial source of microplastic pollution. Currently, a large portion of these fibers end up in wastewater treatment plant sludge, which is often used as fertilizer, thereby dispersing the particles onto agricultural fields.
Challenges with Current Filtration Systems
Manufacturers have been striving to address the microplastic issue by creating filtration systems for washing machines. However, according to Dr. Leandra Hamann from the University of Bonn’s Institute for Organismic Biology, existing filters have limitations. “The filter systems available so far, however, have various disadvantages,” she notes. “Some of them quickly become clogged, others do not offer adequate filtration.”
Dr. Hamann, alongside her doctoral supervisor Dr. Alexander Blanke and colleagues, sought inspiration from nature, particularly from fish that have evolved to efficiently filter water over millions of years.
Certain fish, including mackerel, sardines, and anchovies, filter plankton by swimming with open mouths, utilizing their gill arch system for this purpose. Dr. Blanke, a member of University of Bonn’s “Life & Health” and “Sustainable Futures” research areas, explains, “We took a closer look at the construction of this system and used it as the model for developing a filter that can be used in washing machines.”
Biologically Inspired Self-Cleaning Filter Design
The research team emulated the cross-flow filtration technique seen in fish. The gill arch system functions as a funnel, starting wide at the mouth and tapering towards the gullet, with walls formed by comb-like branchial arches. These structures possess tiny teeth, creating a mesh to filter particles.
“During food intake, the water flows through the permeable funnel wall, is filtered, and the particle-free water is then released back into the environment via the gills,” Blanke explains. “However, the plankton is too big for this; it is held back by the natural sieve structure. Thanks to the funnel shape, it then rolls towards the gullet, where it is collected until the fish swallows, which empties and cleans the system.”
This design assists in preventing clogs by directing particles along the surface and towards the gullet, rather than a direct impact against a solid barrier. The method is highly effective, capturing nearly all plankton. The researchers adapted this system for washing machines, experimenting with various mesh sizes and funnel angles to optimize performance.
Promising Test Results and Future Outlook
“We have thus found a combination of parameters that enable our filter to separate more than 99 percent of the microplastics out of the water but not become blocked,” says Hamann. Laboratory experiments and computer simulations led to this outcome. The simple design, free from complex mechanical components, suggests that production costs could be low.
Microplastics are collected at the filter outlet and removed multiple times per minute. Hamann, now at the University of Alberta in Edmonton, Canada, suggests that the collected plastics could be compressed within the machine, forming a pellet that could be disposed of with regular waste after several washes.
Patent Efforts and Health Implications
The University of Bonn, in collaboration with the Fraunhofer Institute for Environmental, Safety, and Energy Technology UMSICHT, has already filed for a patent in Germany, with an EU-wide application underway. The research team hopes that manufacturers will integrate this filter into future washing machines to curb textile-based microplastic pollution. The urgency of this innovation is underscored by studies indicating potential health risks from microplastics, which have been detected in breast milk, the placenta, and even the brain.
Collaborative Research and Funding
This study involved the University of Bonn and the Fraunhofer Institute for Environmental, Safety, and Energy Technology UMSICHT. Funding was provided by the Federal Ministry of Research, Technology and Space (BMFTR) and the European Research Council (ERC). The Transfer Center enaCom at the University of Bonn, in partnership with PROvendis GmbH, is assisting with the invention’s protection and commercialization, under the NRW university network for knowledge and technology transfer “innovation2business.nrw.”
Original Story at www.sciencedaily.com