Water treatment Surface water PFAS

TECH DIVE: Piecing together the PFAS puzzle

Monday, 25 September 2023

Ahead of the Aquatech Innovation Forum workshop on PFAS, we spotlight some of the latest developments and companies paving the way to solve the PFAS challenge, research being carried out and technology innovation in development.

What are PFAS?

Per- and polyfluoroalkyl substances (PFAS) continue to be a critical concern in the water industry due to their persistence, toxicity, and widespread presence in the environment. 

PFAS, commonly known as 'forever chemicals', are synthetic substances found in various everyday products such as firefighting foam, non-stick cookware, and water-repellent fabrics. Unfortunately, their widespread use has resulted in water sources being contaminated worldwide.

Exposure to PFAS has been linked to serious health problems, including cancer, liver damage, and developmental issues. This contamination in drinking water poses a significant risk to communities.

The main issue with PFAS is that they are highly persistent and do not break down easily in the environment. This means they accumulate in ecosystems, potentially disrupting aquatic life and food chains.

PFAS find their way into water sources through various channels, including wastewater treatment plant discharges. Unfortunately, these treatment methods are often inadequate at removing all PFAS chemicals.

Industrial factories also contribute to the problem as they use PFAS chemicals for various processes, releasing them into local waterways. Extensive studies have been conducted on PFAS contamination in water and the environment, revealing high levels of contamination near industrial facilities where PFAS are used.

Removing PFAS from water and the environment

Communities worldwide continue to face significant challenges in removing PFAS from water. Methods such as activated carbon filtration, chemical oxidation, and membrane treatment are being explored to safely and effectively eliminate PFAS from our water systems. Utilising this knowledge, cities and counties are testing different methods in the hope of ensuring clean and safe drinking water for the future.

Several companies are making strides in PFAS treatment with innovative solutions. Aclarity, a startup based in Massachusetts, US, recently secured $3 million in funding for its solution to remove PFAS from drinking water and wastewater. Aclarity's low-energy, electrochemical process has proved effective in tackling PFAS in landfill leachate and concentrated PFAS streams.

In a full-scale pilot, sponsored by Xylem water technology company, it demonstrated that PFAS can be destroyed at full-scale capacity. Third party lab results using standard ASTM method D7979 confirmed Aclarity destroyed PFAS compounds in landfill leachate continuously at a centralised waste treatment facility at levels of greater than 1,000 ng/L to below 10 ng/L. The equipment operated continuously for four weeks using less than 100 Watt-hr/gallon.

Meanwhile, London company Puraffinity has also raised a significant $13.9 million in Series A funding for its PFAS solution. 
Its patented technology allows for the rapid development of high-capacity adsorbent materials, an approach that engineers the surface of raw materials using tailored molecular groups that trap PFAS compounds and removes them from the water.
The adsorbent media, which can be modified to target different types of PFAS, can operate in Brita type cartridge applications, as well as in large steel tanks or vessels for industrial applications.
“As an advanced precision materials company, our long-term vision includes diversifying into new market segments and exploring broader applications for our adsorbent technology beyond PFAS-related solutions,” says Henrik Hagemann, CEO of Puraffinity (pictured above).

UK PFAS developments

Also in the UK, Nextech was recently awarded a six-figure grant from the government’s Innovate UK organisation for its PFAS removal technology. 

The company says its SMZ technology successfully binds PFAS in existing infrastructure. Nextech has combined two technologies to achieve this the first a low-cost clinoptilolite capture/filter, conditioned with a natural surfactant formulation (FGX3) to remove anionic substances, the second electro coagulation to extract the PFAS in back-wash effluents.
Steve Fox, President of Nextech says the company has also developed “a PFAS concentration and removal technology in backwash effluent to eliminate toxic chemicals returning to the environment and reduce disposal costs”. 

Scientific research and development

Research is ongoing into potential future technologies to tackle the PFAS problem. Scientists in Canada have developed a new filter technology which they describe as a "thousand times better" than a Brita filter. The material they developed can remove long and short chain PFAS chemicals at rates matching or exceeding industry standards, they say. Captured PFAS can be stripped away, making the material potentially reusable or recyclable. To date, the solution is being tested in pilot trials but has not yet been proven at scale in real-world settings. 

“We are hoping to be able to take this to be part of the collective toolbox that we have for addressing PFAS contamination of our water supplies,” says Madjid Mohseni, a professor of chemical and biological engineering at the University of British Columbia.

Elsewhere, Scientists at Saarland University and the University of Illinois have found a method for removing PFAS from water and then immediately releasing them again. The key to this method, they say, is the use of metal-containing polymers called metallocenes, specifically iron-based ferrocene and cobaltocene. These metallocenes act as electrodes that can filter out PFAS molecules from even the tiniest amounts of water. When an electrical voltage is applied, the metallocenes efficiently release the PFAS molecules, allowing the electrodes to be used over and over again. 

Unlike traditional activated carbon filters that need to be destroyed once the PFAS molecules are trapped, this new method offers reusability. This research lays the foundation for larger-scale developments to effectively filter out unwanted chemicals from rivers and oceans, they say.


Predicting the absorption of microplastics in water

Finally, a team of researchers led by the University of Maine has developed an innovative model for predicting the adsorption of microplastics and per- and polyfluoroalkyl substances (PFAS) in water. This model considers various factors such as the characteristics of microplastics, the properties of PFAS, and the chemistry of the water. By utilising this model, researchers can minimise the reliance on extensive lab testing, leading to more efficient development of technologies for PFAS removal.

Through their models, they discovered that polystyrene microplastics are more likely to adsorb long chain PFAS compared to short chain ones. They also found that microplastics in saltwater have a higher adsorption capacity for PFAS than those in freshwater. Moreover, the team identified the polarisability and hydrophobicity of PFAS as the key factors influencing their adsorption into microplastics.

This research is part of the UMaine PFAS+ Initiative, an ongoing effort to address the PFAS pollution crisis with a multidisciplinary approach. 

The water industry is at the forefront of addressing PFAS contamination, driven by a commitment to safeguard public health and the environment. While challenges remain, ongoing research, innovation, and collaboration between industry stakeholders and regulators hold the promise of developing more effective and cost-efficient solutions for conquering the PFAS problem in years to come. 

- The ‘Piecing together the PFAS puzzle’ workshop will take place during the Aquatech Innovation Forum, bringing together viewpoints from regulators, R&D, solution providers and consultants. More information on this not to be missed session can be found here