FEATURE: Halting the rising tide of microplastic pollution – Professional Engineering

Tanya Weaver
Plastic does not belong in our oceans but that is where a huge amount of it ends up. While we’ve seen the footage of plastic rubbish bobbing in the waves and washed up on the beaches, the true danger lurks beneath the surface.
According to the National Geographic, there are 5.25 trillion pieces of plastic debris in the ocean. But the more staggering statistic is the four billion microplastics per square kilometre that litter the deep sea.
This not only has severe consequences for ocean ecosystems and marine life that ingest these microscopic particles, but for human life too through the seafood we consume. A recent study published by Hull York Medical School revealed that these tiny plastic particles we ingest do indeed cause damage to human cells. 
While such studies make headline news today, five years ago the extent of the issue was still relatively unknown to the public. Keen scuba diver and ocean lover Adam Root came to find out about it through a series of talks organised by conservation groups that he attended in Bristol during the summer of 2017.  
Root is also a trained mechanical engineer, and the talks left him feeling shocked at the environmental damage being caused but also inspired to use his engineering skills to do something about it.
“I started out by mapping all the ways plastic enters the ocean and I found that the largest proportion by a nautical mile is microplastic. I then researched what was being done about it and the answer that revealed itself to me was very little because once it gets in our waterways and into the ocean it’s technically very difficult to remove. So it needed to be stopped at the source,” says Root.
More research revealed that most of the microplastics are generated through the process of washing clothing. These are the tiny strands of plastic thread, less than 5mm long, that are shed from synthetic fabrics during washing. 
He says: “A washing machine is like a cheese grater inside. Every time you wash something it breaks it down a bit. In the UK, we’ve got 24 million domestic washing machines with each producing about a gram of microplastic per wash. That works out to 14-16 tonnes a day of material going down the drain. If it’s a flood scenario where we have high rain, which happens about 400,000 times a year, that water goes straight out without being filtered in the wastewater treatment plants. It then makes its way into our rivers and the ocean.” 
In July 2017 Root quit his job as a senior design engineer at Dyson where he’d been working on product innovation. He readily admits it was a scary move because, although he enjoyed his time at the company, which he had joined five years previously as a graduate design engineer, he wanted to use his experience in designing domestic goods to create some sort of filter for washing machines that could capture microplastics. 
He set up his own design consultancy called Inheriting Earth, which afforded him some income. He then put a pitch together and with it won a £250 ‘Will It Work?’ grant from the Prince’s Trust. With this money he built a rig using a bucket, wood and an old washing machine that he’d taken apart.
He explains: “I placed the bucket on top of a small oak table I’d built. I put the washing machine pump inside the bucket, which pushed water through the microplastic filter I’d made and so draining the clean water into the bucket. This created a little circular loop. To imitate the microplastic, I shredded the elastic from a pair of pants – which is essentially what happens in the inside of a washing machine – and sprinkled that in the water.” 
Although crude, the rig proved that his retrofit washing machine filter worked. From here things started to escalate for Root. He was given Innovate UK’s Innovator of the Year Award in 2018 and that year was also asked to represent the UK at the G7 Summit in Canada. He also attracted investment, which enabled him to take on his first two employees, one of whom was fellow engineer Reuben Kettle Aiers who had worked with Root at Dyson, and together they developed the prototype.  
(Credit: Sam Gibson)
Four years later, Matter (of which Inheriting Earth is the holding company) operates out of a warehouse near Bristol’s city centre. It’s a vast space featuring an open-plan office, an R&D facility that is partitioned off behind a large curtain, and what looks to be a laundry with various items of clothing draped over washing lines. “We do thousands and thousands of cycles to make sure our filter product is not only efficient but robust. So a benefit of working here is you get your washing done for free,” smiles Root.
Behind the curtain, the R&D lab is equipped with various technologies and 3D printers as well as all the prototypes that were created and iterated upon on the journey towards the final product. Root explains: “We’ve developed our own design process using roughly the Technology Readiness Levels process but added a bit of colour into it for stuff like marketing, intellectual property and usability. We’ve gone from really rudimentary models made from wood and plastic through to a production-ready product.”
The device, called Gulp, was soft launched at the end of 2021, with a proper launch planned for later this year. Connected between the outflow pipe and the drain, this retrofit washing machine filter captures microplastics as they leave the machine in the wastewater.
A tiny, red, squiggly piece of microplastic seen against the white surface of the washing machine does seem small and inconsequential. But these fibres soon accumulate and Root estimates that 240g of microplastic is captured in just one of its domestic washing machine filters each year. Multiply that amount by every washing machine in a UK home and it soon becomes apparent how tonnes and tonnes of microplastic are entering our waterways. “While not all of these fibres are plastic, with 65% of all garments today made of synthetic materials, a lot of them are,” says Root.
The key innovation with Gulp, and which posed the biggest engineering challenge during the design process, is that the device features no replacement parts or disposable filters. Instead, the filter is emptied once a month and then reused. “Most filtration technology, including the medical face masks we’ve been wearing during Covid, works by capturing the material and embedding it in the filter, which is then effectively disposed of,” says Root. 
“Microplastics is quite a simple thing to capture, what’s hard to deal with is everything else. All sorts of things go through the wastewater network, from skin cells and silica through to disposable nappies. What we’ve been working on for a number of years is the technology to do that efficiently and to make it scaleable.”
With one of the company’s founding principles being that of supporting a circular economy, the ambition is not merely to pioneer technology solutions for capturing microplastics but for harvesting and recycling them too. Currently, Gulp customers are being asked to send their captured microplastics to Matter, which is researching ways of feeding this material back into the manufacturing process where it can be used to make new products. “It will be a complete closed loop, cradle to cradle. That is the mission and we’re working to achieve that,” says Root. 
While the ambition is admirable, being a sustainable company is challenging but it’s a challenge that Matter is determined to meet. Indeed, one of Matter’s first employees was a sustainability officer to ensure that the company’s impact on the environment remains minimal. “Sustainability is part of our company mission and DNA,” says Root emphatically. 
“We look at five key criteria in terms of how we operate as a company. The first is material health and being very particular about the types of sustainable materials we select. The second is material reutilisation, which is about how recycled and recyclable is the material we are using. The third is energy usage. 
“The fourth is water stewardship and ensuring that we are not producing microplastic in our testing facility. In fact, we have designed our own capture system for harvesting the water. The final criteria is social fairness and setting standards for the types of businesses we work with.” 
Having successfully secured investment from Builders Vision’s Rising Tide Fund and the British Design Fund, Matter is looking to scale up its activities across three spheres – R&D, education and legislation. Currently in the process of selecting a supply chain to scale up the making of its Gulp product, Matter is working with white goods manufacturers to incorporate its technology into new products in the coming years. It is also developing filtration systems for integration inside washing machines. One of the key areas where it is campaigning for change is for the UK to follow France’s lead in making it illegal to buy a washing machine without a microplastic filter from 2025.
But the source of the problem is higher up in the design and manufacture of textiles, which needs to change to prevent microplastics ending up in our washing machines in the first place. In the meantime, Root says we all need to do what we can to prevent climate change. As he puts it, “We can’t decide not to do this. We will be burning banknotes to stay warm if climate change happens the way scientists predict it will as the financial system will mean nothing.”
He believes that engineers have a key role in creating the solutions to tackle climate change. “Engineers are often making the decisions in a design process and have such a responsibility to set the intention of a product,” he says. “Fundamentally, it’s about cradle to cradle and designing a system that is circular. If we nail that, we not only protect earth, it allows us to look beyond earth and become a spacefaring nation.”
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