Fish biology inspires a novel microplastic laundry filter

Engineers turn fish biology into a breakthrough microplastic laundry filter

Inspired by the filter feeding mechanisms of basking sharks and manta rays, a startup called Cleanr has developed a filter that traps over 90% of microplastics released in each wash cycle.

By Devin Nunnari

Let the best of Anthropocene come to you.

Max Pennington’s epiphany happened in the laundry room. As an engineering student at Case Western Reserve University, in Cleveland, Ohio, Pennington became deeply concerned about microplastic pollution—particularly microfibers pouring into waterways via washing machines. He wanted to see the problem for himself, so he teamed up with some classmates and created a filter from household products: a bit of mesh, an old cup, and some duct tape.

After one load of laundry, the filter was chock full of microfibers—debris from the breakdown of synthetic clothing. “Once we saw what came out of the washer hose, we knew it was something that needed to change,” said Pennington. Along with his classmates Chip Miller and David Dillman, he got to work creating a solution, in the late nights and early mornings around their class schedules. Huddled around monitors on the sixth floor of the Sears Thinkbox, a giant open-access makerspace, the three began building their first washing machine filter prototype. It uses a process modeled on how manta rays and basking sharks filter feed, to help keep microplastic pollution out of waterways.

Clothing and washing machines are the number one source of microplastic pollution—as many as 1.5 million fibers can be released from a single synthetic garment during a wash cycle.

“People are becoming more aware of microplastic pollution,” Pennington says, but fewer people know “that our clothing and our washing machines are the number one source of them.” Synthetic fibers now make up more than two-thirds of all fabrics produced each year, and as many as 1.5 million fibers can be released from a single synthetic garment during a wash cycle.

The exact amount varies. According to a study published in 2024, heavier fabrics—which are also potentially more durable ones—release more microfibers than lighter ones. Woven fabrics shed more than knit ones. Pre-wash cycles lead to even more pollution. And, in a particularly thorny problem for sustainability, recycled polyester sheds more than new fabric. Other factors include detergent type, water temperature, and the length of the wash cycle.

On top of all that, more people worldwide are purchasing washing machines: the number in use in households grew from 840 million in 2013 to 1.1 billion in 2020.

Yet one thing is clear: All that pollution is no match for traditional washing machine filters, or for wastewater treatment facilities that clean water before returning it to streams and rivers.

Sitting around their office late one night, Pennington, Miller, and Dillman began brainstorming things that perform filtering functions naturally. They landed on fish. Manta rays have cone-like mouths with parallel arrays of ridged lobes that cause plankton to ricochet off the filter walls and funnel straight down the ray’s throat, allowing water to separate into their gills. They studied the existing research on the physics of just how these filter-feeding fish separate food from water, then used that process as a model. Other researchers, like a team at MIT that got inspiration from mobula rays to inform water filter improvements, have looked to filter feeding fish to help guide engineering breakthroughs.

As soon as they started printing 3D designs inspired by the fishes’ mouths, they realized they had found a solution. Their patented technology, called Vortx, creates small vortices that separate and suspend microplastics and other particles in the center of the filter, reducing the amount of clogging that occurs. The plastics then flow to the back of the Cleanr filter into a disposable pod, making the design easy for consumers to use. The filter, sold directly to consumers for $299, is external and sits on top of or next to a washing machine.

Cleanr’s filter removes over 90 percent of microplastics released in each wash cycle, collecting particles as small as 50-microns, or around the width of a piece of hair. Pennington says it also clogs less than other filters. In fact, one of Cleanr’s early prototypes flooded Pennington’s college apartment. Another became clogged with dog hair. After that result, the team began sourcing dog hair from local groomers to test future prototypes.

Though Cleanr’s filter is innovative, it still faces competition. Other microfiber filters and solutions are already on the market, and more are on the way. The Cora Ball, a sphere layered with plastic coils, removes 30 percent of microplastics per load, while the Guppyfriend Bag, a mesh sack used to hold clothes, reduces between 80 and 100 percent. The PlanetCare, another external filter, reduces 98 percent per load—though it can be challenging to install and may not work well for pet owners. Meanwhile, researchers in Japan have successfully used sound waves to filter out microfibers.

Yohancha via Flickr

Their design inspired by the fishes’ mouths creates small vortices that separate and suspend microplastics and other particles in the center of the filter, reducing the amount of clogging that occurs.

To speed the uptake of microfiber filters, Cleanr is partnering with universities to install them in dormitory laundry rooms. Case Western Reserve and the University of Akron are backing the new technology by installing the filters in some of their dorms.

Ultimately, though, legislation may be the only way to integrate microplastic filters in every washing machine during manufacturing. Some countries are beginning to mull regulations requiring manufacturers to build microplastic filters into new washing machines. In 2021, the Australian government released its National Plastics Plan, which proposed phasing in filters in new washing machines by 2030. France began requiring microfiber filtration in new washing machines at the beginning of 2025, and the UK is considering similar legislation.

In the US, New Jersey, Oregon, and Illinois have introduced legislation to require microfiber filters in washing machines, and bills recently introduced in both the U.S. Senate and House would require all washing machines manufactured after 2030 to include or offer microfiber filtration—though it’s unclear what the future of those bills might be.

Another solution is to filter out microplastics downstream—at wastewater treatment facilities, before the water is released into waterways. Studies have found that it is possible to eliminate close to 100 percent of microplastics by using a variety of technologies at different stages of the treatment process—including mesh screens, enzymes, membrane bioreactors, and emerging technology like magnetic extraction, which uses iron nanoparticles. But reaching high levels of elimination is expensive—and often results in releasing the microplastic back to the environment anyway, in the form of sludge or other waste.

In the meantime, Pennington hopes to increase consumer awareness about plastic pollution from laundry. “It is critical to fight this problem head on,” Pennington said. “We want to make it as easy as possible for people to be a part of the solution.”

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