The dinky device slots seamlessly into the modest space above my washing machine. A pipe snakes down from it, drawing in wastewater from my clothes washes. At the end of each wash cycle, the machine makes a polite whirring noise: that’s the sound of the groundbreaking bit of technology working, according to its inventor, Adam Root. That invention is a microplastics filter.

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

About three weeks after it was installed, it beeps to tell me it’s time to empty it out. I remove the canister and scoop out the contents with the built-in scraping tool pressed into the lid like a yoghurt spoon. My excavations reveal a surprisingly substantial stew of grey matter – probably a grim mixture, Root tells me, of microfibres, skin cells, hair and dust.

Root’s invention is the basis of his Bristol-based company, Matter Industries, which claims it can capture 97% of microfibres before they escape a washing machine. In 2025, it made Matter a runner-up in the oceans category of the Earthshot prize. (Root was just behind Rebecca Hubbard, the director of the High Seas Alliance, who campaigned to create the historic high seas treaty.) Matter’s filter is now available in more than 30 European markets and the UK, and the company plans to expand to the US.

The experiment that led to all of this unfolded a few years ago on a wet garage floor, littered with buckets, and with an investment of just £250 behind it. Root had rigged up 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 recalls. After a few dicey attempts, he says, “I managed to get something that worked. I demonstrated I could capture microfibres.”

His invention joins others including Xeros, and the US-based Cleanr and Filtrol, that work to filter out microplastic before it reaches waterways.

His filter cleaning itself is, according to Root, what makes his particular invention unique. Matter Industries finds that each wash cycle produces about 1g of fibre waste, and to capture as much as possible the mesh must be especially fine. But this makes filters prone to blockage, so Root’s version rinses itself after each wash, clearing the mesh surface so that wastewater can continue flowing through.

The machine doesn’t just capture plastic textile fibres but all types. And that’s a good thing, says Anja Brandon, the director of plastics policy at the US non-profit 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.” The instructions warn you to place the waste into the bin, not wash it down the drain.

An estimated 69% of all clothing contains fossil fuel-based plastic textiles such as polyester, nylon and acrylic, which shed billions of fibres into the environment. In the UK, domestic washing machines annually discharge between 6,000 and 87,000 tonnes of clothing fibre into rivers and ultimately the ocean. The US’s bigger population, more frequent washes, and penchant for activewear means it produces significantly more.

Several studies show that microfibres are the most ubiquitous type of 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,” says Brandon. They can constitute more than 90% of the microplastics that marine animals consume, and are present in the air, our drinking water and food.

Root would ultimately like to see his filters in municipal wastewater treatment plants to capture as much microplastic as possible before it enters the sea. He is also campaigning for legislation to get microfibre filters into all washing machines in the UK.

Root started out as a mechanical engineer and then moved into a role in product innovation at Dyson. But he says it was scuba diving that opened his eyes to the extent of ocean pollution. “I didn’t really feel like I was doing anything super-positive,” he says. He then quit his job to go solo. “I thought there was an opportunity to go change some big-picture stuff.”

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

Matter will soon be piloting its technology at an industrial scale in textiles factories across Portugal, Egypt and Bangladesh. Factories produce kilometres of fabric each day, all of which need multiple rounds of washing and dyeing. That process wrings out huge quantities of fibre waste – 360 tonnes annually, in the case of one factory Matter sampled in its field research – which is sometimes discharged directly into rivers. Catching domestic microplastics is crucial, but industrial effluent is a big global polluter too. “You have to be where the pollution is,” Root says.

Not everyone agrees that this is where our pollution-fighting efforts should be trained, however. Richard Thompson, professor of marine biology at the University of Plymouth, first alerted the world to the threat of microplastics in a landmark 2004 study. His team’s research has since found that microfibres become a problem long before the laundry stage. “Most of the world’s population probably don’t have a washing machine,” he says. “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’s concerned that if we overestimate downstream fixes, we’ll overlook the important things we need to fix upstream, such as designing better textiles. Thompson highlights the developing global plastics treaty as a venue where countries can work together to bring about such system changes.

Root agrees that textile redesign is critical. But he worries about the time it could take to improve synthetic textiles, especially as they’re intertwined with the enormous global oil industry. Alongside long-term efforts to shift the system, he thinks filters are an available tool that can help alleviate the damage now. “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 says. “I think you have to look at what you can change.”