Toxic forever chemicals have travelled as far as the Arctic Ocean, and were recently found pounding our coastlines on the back of ocean spray, making their removal from the environment all the more imperative.
So far, per- or poly-fluorinated alkyl substances (PFAS) remediation has been beset with obstacles. In the UK, it could cost £21 billion (around €25 billion) to remove all forever chemicals from our sewage alone, according to UK Water Industry Research (UKWIR).
Even if we did foot that bill, a question mark still hangs over the efficacy of the available technology.
But Oxyle, a Switzerland-based company, has discovered a way to dramatically clear PFAS-contaminated water while reducing costs.
“A lot of bottled water has PFAS in it,” says Fajer Mushtaq, Oxyle’s co-founder. “We're even lower than bottled drinking water after our treatment.”
The technology builds on Mushtaq’s doctoral thesis at ETH Zurich, where she developed nanoparticles that could oxidise and destroy PFAS. Having grown up in Delhi, her research was inspired by the city’s water crisis.
“Not having access to water whenever I wanted or rationing it in the months of summer, that leaves an imprint on you,” she says. “Since I was a child, I knew this is a really important resource which needs to be valued, and what happens when you don't take good care of it.”
Why is PFAS removal so difficult?
PFAS’ heat-proof, water-repellent properties make them attractive materials for hardwearing consumer products (like non-stick pans, waterproof clothes and stain resistant fabrics), but it also means they are hard to destroy.
When we wash clothes containing these forever chemicals, we inadvertently send them into our waterways through wastewater. PFAS are also present in some pesticides and firefighting foam.
The precise effects that PFAS can have on our health are still emerging, but studies have linked forever chemicals with some cancers (including kidney and prostate), a reduced immune system, hormonal changes and high blood pressure.
Their release into the environment is endemic and, with some PFAS taking more than 1,000 years to break down, they have accumulated in vast quantities. Their sheer ubiquity presents an expensive problem.
“They're called ‘forever chemicals’ for a reason,” says Karyn Georges, who co-authored a UKWIR paper on PFAS solutions. “They're not easily biodegradable. They're not easy to remove. That's why they were used in the first place.”
Complicating matters is the variation between PFAS. “There are more than 10,000 different PFAS,” Georges continues. “They comprise a whole range of physical chemical properties, and by that, I mean different ways you can potentially remove them.”
PFAS remediation methods can largely be split into three categories: adsorbents, separation and destruction.
Adsorbents and separation are both effective at removing PFAS from wastewater, but neither eradicates the offending chemicals.
Adsorption typically uses granular activated carbon (GAC) to draw PFAS from wastewater. The leftover carbon is then contaminated and needs disposing of - but sending it to landfill risks further pollution, as PFAS seep into the soil and groundwater.
“You have to destroy them, otherwise you're just circulating them to different media, be it sludge or even air,” says Georges.
In 2021, the UKWIR labelled incineration the only way to permanently destroy PFAS. This usually requires burning at temperatures above 1,000°C, spending huge amounts of energy.
Some studies have questioned whether incineration even destroys PFAS completely, or if it allows airborne particles to escape and form air pollution.
It may also release greenhouse gases like tetrafluoromethane and hexafluoroethane.
How does Oxyle work?
“We are purely destruction tech,” says Mushtaq. “We are oxidising and reducing these chemicals.”
Oxyle removes PFAS by chipping away at the bonds between molecules, breaking down long and short chains into their composite parts, which are safe to dispose of.
“Let's say you have a carbon hydrogen bond. We break it. You have a carbon fluorine bond, you break it,” says Mushtaq. “At the end of the treatment, all you're left with is CO2, water molecules, some fluorides, sulphates and minerals - basically, building blocks.”
The chemistry isn’t new, she explains, and is already in use with several companies. What sets Oxyle apart is how it creates energy to facilitate the reaction.
Where others might pass electricity through electrodes or apply UV light to the wastewater (both expensive and energy-intensive processes), Oxyle uses mechanical energy, like vibrations produced by bubbles or water flow.
It then applies the nanoporous material created during Mushtaq’s PhD to the water, where it forms a catalyst. “It gets activated and starts to split the water and forms different chemical species that are able to break the bonds of these PFAS molecules,” she says.
Using bubbles reduces Oxyle’s energy use by at least 15 per cent - in some cases even 60 per cent. “Energy is the biggest driver of cost for destruction tech,” says Mushtaq, which means Oxyle can offer lower operational expenses than its competitors.
“Our technology is quite modular,” she continues. “Each reactor can treat about 10 metre cubes an hour, which is 10,000 litres an hour.”
This gives Oxyle flexibility to scale their operations up, adding more reactors for larger customers.
Who is Oxyle working with?
Treating PFAS in wastewater is a costly business which, according to Georges, is largely shouldered by people’s water bills.
“The UK public are paying for the removal,” she says. “Companies producing those chemicals should be paying water companies, for example, to remove those chemicals.”
Oxyle already has such PFAS-producing companies within their sights. “It's mostly industrial players,” says Mushtaq. “The ones who are either producing these chemicals and have to treat the wastewater or have contaminated the facilities around and need to do remediation.”
Oxyle completed a pilot with Swiss chemicals company CIMO last year, when it treated groundwater contaminated by PFAS. Mushtaq says that Oxyle removed 99 per cent of the polluting compounds every day for six months.
“The kicker was we were able to do that at energy value, which they have never seen in the construction space before,” she says. That energy use equated to just over two kilowatts per metre cubed in an hour. “The nearest competition is around 20 kilowatt hours, which is 10 times higher.”
The limits of PFAS removal
Nonetheless, Oxyle is working against a monumental tide. With all the historic PFAS pollution, and the continued torrent leaking into the environment, we will need more than remediation to rid ourselves of forever chemicals.
“We're not removing it as fast as the pollution is happening,” says Shubhi Sharma, a researcher at CHEM Trust. “Stopping pollution at source has to be the priority. Remediation technologies can be applied in parallel, but they are a sticking plaster.”
While the EU has proposed a blanket ban on 10,000 PFAS from 2026, Sharma says regulation in the UK has been at a standstill.
“The lack of action in the UK on PFAS regulation is shocking,” she says. Prior to Brexit, she explains, a series of international treaties restricted PFOS, PFHxS, PFOAs and TDFAs (four types of PFAS that received international attention for their impact on health and the environment) but no new regulations have been introduced since.
“The UK government needs to align with the EU and bring forward a universal PFAS restriction as well.”
But, she cautions, there’s no instant fix for PFAS. PFOS was banned by the Stockholm Convention in 2009, yet still appears in the environment due to its persistence.
“As a company that does remediation of PFAS, we will be existing for decades,” says Mushtaq. “The sooner we ban the use of them the better, because it's less remediation needed.”
