Invisible, pervasive microplastics are the most intangible but intractable pollution problem of our time. But new research from the University of Bonn [50.7°N, 7.1°E] could stop the spread of this gloomy attitude: Based on the way fish have filtering particles from water for millions of years, researchers have designed a filter that could prevent the vast majority of microplastic fibres from ever leaving our homes in the first place.
A big problem hiding in plain sight
Washing synthetic clothing sheds tiny plastic fibres into wastewater. Even the best sewage treatment plants cannot fully solve the problem: although most fibres are captured, they accumulate in sewage sludge, which is often spread on agricultural land, quietly re-introducing plastics back into waterways and soil; entering our food in a highly undesirable cycle.
When it comes tackling the problem at source, the “turning the tap off” analogy is close to the truth.
Fish teaching man sustainability
Many fish feed by filtering particles from water as they swim, using delicately structured gill arches that guide food towards the throat while clean water flows away. Crucially, these systems do not clog, despite operating continuously in particle-rich environments.
The researchers translated this biological insight into an elegant engineered device: a fish-inspired filter that uses a gently conical shape and angled flow to keep fibres moving rather than stuck. Instead of forcing all water straight through a mesh (as most filters do), the design encourages particles to roll, slide and concentrate towards an outlet, where they can be periodically flushed away: Less of a sieve than a living system.
Near-total capture, without the clogging
The results are remarkable. In laboratory tests, the filter captured up to 99.6% of microplastic fibres, at least as high as existing solutions. But beyond this stat; while traditional filters trap fibres inside the filter itself, leading inevitably to clogging, rising pressure, and frequent maintenance, this new design actively moves most fibres out of the filter during periodic self-cleaning, collecting them in a small concentrate stream that accounts for only about 5% of the total water volume.
In effect, this means:
- Far less clogging
- Much longer operating life
- Less energy use
- Easier disposal of captured plastics
It is not only efficient, but practical.
Small design choices, big performance gains
One of the most impressive aspects of the study is how carefully the researchers explored the details. They show that performance depends on subtle factors such as the angle at which water meets the filter surface, the geometry of the inlet, and the timing of cleaning cycles.
At shallow angles, fibres are more likely to keep rolling instead of sticking. With the right inlet design, flow becomes smoother and more effective. With periodic back-flushing, the system clears itself before problems arise. This is biomimicry as engineering discipline.
Important implications beyond washing machines
Although the immediate application is domestic laundry, the implications are wider. Microplastic pollution is a systemic problem, and solutions that work at scale must be robust, low-maintenance and easy to integrate into everyday infrastructure.
This research demonstrates that:
- High microplastic retention is possible without complex membranes
- Self-cleaning filtration can dramatically reduce maintenance burdens
- Nature-inspired designs can outperform conventional approaches
It also quietly challenges an assumption that has shaped water policy for decades: that pollution must be dealt with downstream. Instead, it shows how source-level interventions can be both simpler and more effective.
A hopeful note in a difficult story
Microplastics are often framed as a problem we have already lost control of. This paper offers a rare counterpoint: a solution that is clever, grounded, and ready to be developed further.
Learning from fish, the researchers have shown that we do not always need more complex technology. Fresh ideas can be better.
If even a fraction of washing machines were equipped with filters like this, the reduction in microplastic emissions would be immediate, measurable and lasting. It is a reminder that progress on environmental challenges does not always arrive with grand gestures. Sometimes, it begins with a mesh, an angle, and a little humility towards nature’s engineering.
Source
A self-cleaning, bio-inspired high
retention filter for a major entry path
of microplastics, NPJ Emerging Contaminants, 2025-12-05
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