Inventor’s Washing Machine Filter Captures 97% of Microplastics

A compact device installed above a washing machine uses a pipe to draw wastewater from clothes washes. At the end of each cycle, the machine emits a polite whirring noise that inventor Adam Root says indicates his groundbreaking microplastics filter is working.

“The most common thing we hear [from customers] is: ‘I cannot believe how much material is coming out of the washing machine,'” Root said. “Somebody sent me [photos of] dinner-platefuls.”

About three weeks after installation, the filter beeps to signal it needs emptying. The user removes a canister and scoops out contents using a built-in scraping tool stored in the lid. The extracted material is a substantial stew of grey matter that Root described as a mixture of microfibers, skin cells, hair and dust.

Root’s invention forms the basis of his Bristol-based company, Matter Industries, which says the filter captures 97% of microfibers before they leave a washing machine. In 2025, the company was a runner-up in the oceans category of the Earthshot Prize, just behind Rebecca Hubbard of the High Seas Alliance. The filter is now available in more than 30 European countries and the UK, with plans to expand to the United States.

The experiment leading to the filter began on a wet garage floor with buckets and a £250 investment. Root rigged a temperamental old washing machine with a homemade microplastic filter. “I was turning this thing on and off with a broom handle; it was pissing water all over the place. I was terrified of electrocuting myself,” he recalled. After a few dicey attempts, he said, “I managed to get something that worked. I demonstrated I could capture microfibres.”

His invention joins others, including Xeros, Cleanr and Filtrol, that filter microplastics before they reach waterways.

The self-cleaning feature makes Root’s filter unique, he said. Matter Industries finds each wash cycle produces about 1 gram of fiber waste, requiring a very fine mesh to capture it. That mesh is prone to blockage, so Root’s filter rinses itself after each wash to clear the surface and allow continued flow.

The filter captures not only plastic textile fibers but all types, which is beneficial according to Anja Brandon, director of plastics policy at the Ocean Conservancy. “Plastics are our chief worry with microfibres, but other textiles are chockful of chemicals and colourants, and we know they have impacts as well,” she said. Instructions direct users to dispose of waste in the bin rather than down the drain.

An estimated 69% of all clothing contains fossil-fuel-based plastics like polyester, nylon and acrylic, which shed billions of fibers into the environment. In the UK, domestic washing machines discharge between 6,000 and 87,000 tonnes of clothing fiber annually into rivers and oceans. The United States, with its larger population, more frequent washing and preference for activewear, produces significantly more.

Several studies show microfibers are the most ubiquitous microplastic in the environment. “They’re among the most common types of microplastics found in tissue samples of species across the board. So they’re a massive part of the problem,” Brandon said. They can constitute more than 90% of microplastics consumed by marine animals and are found in air, drinking water and food.

Root ultimately wants his filters installed in municipal wastewater treatment plants to capture microplastics before they reach the sea. He is also campaigning for legislation requiring microfibre filters in all washing machines in the UK.

Root began his career as a mechanical engineer and later worked in product innovation at Dyson. Scuba diving opened his eyes to the extent of ocean pollution. “I didn’t really feel like I was doing anything super-positive,” he said. He quit his job to work alone. “I thought there was an opportunity to go change some big-picture stuff.”

A small grant from the Prince’s Trust allowed him to build that garage-floor prototype, which won Innovate UK’s Young Innovator of the Year award and helped launch his company in 2018. Since then, Matter Industries has raised $20 million (£15 million), employs 50 people, and partnered with Bosch and Siemens to manufacture units containing Matter’s Regen filtering technology.

Matter will soon pilot its technology at industrial scale in textile factories in Portugal, Egypt and Bangladesh. Factories produce kilometers of fabric daily, requiring multiple washing and dyeing cycles, generating large quantities of fiber waste — 360 tonnes annually at one factory Matter sampled — sometimes discharged directly into rivers. “You have to be where the pollution is,” Root said.

Not everyone agrees that filters should be the focus. Richard Thompson, a marine biology professor at the University of Plymouth who first alerted the world to microplastics in a 2004 study, found that microfibers become a problem long before laundry. “Most of the world’s population probably don’t have a washing machine,” he said. “We showed that more than half of all the [microplastic] emissions actually occur while you’re wearing the clothes.”

Thompson sees microplastic filters as “part of the answer,” adding: “I certainly don’t want to pour cold water on any potential solution.” But he worries that overemphasis on downstream fixes could overlook upstream improvements like better textile design. He highlights the developing global plastics treaty as a venue for countries to work on systemic changes.

Root agrees textile redesign is critical but worries about the time needed to improve synthetics intertwined with the oil industry. Alongside long-term systemic shifts, he sees filters as an immediate tool. “I kind of imagine myself being knee-deep in shit. You’ve got your shovel, and you just have to start at your feet and work your way out,” Root said. “I think you have to look at what you can change.”