Researchers at the University of Bonn have developed a groundbreaking filtration system inspired by the natural feeding mechanism of fish, offering a powerful new solution to the growing problem of microplastic pollution from washing machines. Early tests show that the newly designed filter can remove more than ninety nine percent of plastic fibres from laundry wastewater, marking a major advance in efforts to protect water systems and public health.
The findings have been published in the scientific journal npj Emerging Contaminants, and the design has already entered the patent application stage in Germany, with European-wide patenting now underway.
Washing machines emerge as a major source of microplastic pollution
Microplastics released during washing are increasingly recognised as one of the most significant sources of plastic pollution. According to researchers, a single washing machine in a household of four can release up to five hundred grams of microplastics every year. These particles are shed from fabrics as they wear down during routine washing cycles.
Once discharged, the microplastics enter wastewater treatment plants and become trapped in sewage sludge. Since this sludge is often reused as agricultural fertiliser, the plastic fibres can spread into soil, crops, and eventually the food chain.
Seeking a more effective and durable solution, researchers turned to biology for inspiration. Certain fish species such as anchovies, sardines, and mackerel feed by filtering water as they swim, using a highly efficient gill arch system to trap plankton.
The research team closely examined this natural system, which has evolved over hundreds of millions of years. The fish gill structure functions as a funnel-shaped filter, allowing water to pass through while guiding particles along the surface rather than trapping them head-on.
This principle, known as cross-flow filtration, prevents clogging and allows the system to clean itself continuously.
Self-cleaning design prevents blockages and boosts efficiency
Unlike conventional filters that clog quickly, the fish-inspired filter allows microplastic fibres to roll along the mesh surface toward a collection point. Clean water flows through the system, while plastic particles are separated and gathered without obstructing the filter.
By adjusting the mesh size and the funnel opening angle, the researchers identified a design that achieves extremely high filtration efficiency without blocking. Laboratory tests and computer simulations confirmed that the filter removes more than ninety nine percent of microplastics while remaining fully functional over time.
The filter contains no complex mechanical parts, making it inexpensive and practical for mass production. Microplastics collected by the filter are regularly suctioned away and compacted into small pellets, which can be removed after several dozen washing cycles and safely disposed of with household waste.
Researchers believe this approach could be easily integrated into future generations of washing machines, significantly reducing microplastic pollution at its source.
Health concerns add urgency to microplastic control efforts
Scientists warn that microplastics are not just an environmental issue but a growing health concern. Studies have already detected plastic particles in breast milk, the placenta, and even the human brain, raising serious questions about long-term health effects.
By targeting one of the largest entry points of microplastics into the environment, the newly developed filter could play a critical role in limiting human and ecological exposure.
Next steps focus on industry adoption and global impact
The research was conducted in collaboration with the Fraunhofer Institute for Environmental, Safety, and Energy Technology and supported by funding from national and European research bodies. The team now hopes that appliance manufacturers will adopt and refine the technology for commercial use.
If widely implemented, the fish-inspired filter could help stem the flow of microplastics from textiles, offering a practical and scalable solution to a problem that continues to grow with global reliance on synthetic fabrics.