A sustainable solution to remove ‘forever chemicals’ from wastewater & air emissions for good

The omnipresent and potentially toxic per- and polyfluoroalkyl substances (PFAS) have quietly permeated our world. For this reason, the EU persistent organic pollutants (POPs) regulation and other legislations are restricting the use and emission limits of these molecules in industrial wastewater and air emissions. However, DESOTEC has developed a secure and POP-compliant removal method that enables manufacturers to permanently and sustainably address the persistent challenge of ‘forever chemicals’.

What’s the fuss about PFAS?

PFAS compounds belong to a group of thousands of man-made chemicals. In 2021, the Organization for Economic Cooperation and Development (OECD) defined PFAS as fluorinated substances that contain at least one fully fluorinated methyl or methylene group. Because of their high thermal and chemical resistance, manufacturers across many sectors have tapped into PFAS: Food packaging and preparation (e.g., non-stick pans), cosmetics (e.g., makeup), textiles, firefighting foam. You name it. However, the industrial functionality of PFAS-containing products has turned into an environmental legacy. PFAS can now be found everywhere across the globe, even in drinking water sources. In fact, if production wastewater is not properly treated, PFAS may enter both surface and ground water, where they break down very slowly or not at all. That’s why they are dubbed as ‘forever chemicals’. Recent studies revealed the presence of PFAS in tap water across the US as well as over 17,000 contaminated sites around Europe. Also, with researchers unearthing the potential negative effects on human health of PFAS’ excessive exposure, regulations on their use and emissions are becoming increasingly stringent.

The PFAS legislation landscape

The EU was a global pioneer on PFAS control. The POPs regulation has restricted the use of perfluorooctane sulfonate (PFOS), one of the most widely applied ‘forever chemicals’, since 2009. EU regulators have then widened the legislation scope to include other PFAS compounds such as perfluorooctanoic acid (PFOA) and perfluorohexane sulfonic acid (PFHxS). In February 2023, the European Chemicals Agency (ECHA) changed gear by proposing to ban 10,000 PFAS compounds. Once approved, this landmark regulation will affect both EU-based producers and their non-EU suppliers for PFAS use on their own, in mixtures, and in products. Waiting for PFAS to be eradicated by European industrial processes forever, the EU revised its Drinking Water Directive to introduce a limit of 0.5 µg/l for all PFAS. On top of that, the European Commission proposed to add a series of PFAS among the controlled chemicals released both in groundwater and surface water.

US legislators are scrutinising general PFAS emission. In 2021, the Environmental Protection Agency (EPA) released a PFAS Strategic Roadmap to limit their pollution. In particular, companies discharging PFAS-tainted wastewater must comply with an emission limit which mostly depends on the quality standards of the receiving water. In the USA, the reactivation of PFAS-containing activated carbon has been promoted by the American Department of Defense (DoD) to effectively destroy PFAS.

Considering this regulatory scenario and the low PFAS removal efficiency of conventional wastewater treatments, companies have to look into more adequate purification technologies to keep up with the compounds restriction.

PFAS removal methods

According to both researchers and regulators, the three most ready-to-use technologies to treat PFAS include membrane separation, anion exchange resins (AER), and activated carbon. Also, the Stockholm Convention’s guidelines recommend activated carbon as best available technology (BAT) for removing PFAS from a polluted stream (i.e., waste, air, liquid, or gas).

Membrane separation

Membranes are a solid porous media that can separate a certain pollutant from a liquid or gas phase. Based on PFAS properties (e.g., molecule size), reverse osmosis (RO) and nanofiltration (NF) are one of the most suitable separation processes. Previous studies found these methods to be effective at removing PFAS from water. On the other hand, they require an upstream pre-treatment (e.g., activated carbon filtration) to prevent membrane fouling and extend their lifespan.

Anion exchange resins

As the name suggests, this purification route entails swapping the negatively charged PFAS ions dissolved in water with some other anions (e.g., chlorides) embedded into a polymeric resin bed. This exchange occurs through an adsorption mechanism. Resins exhibit great adsorption capacities and effectively remove a wider range of PFAS. Nonetheless, being a less mature technology, its cost was estimated to be three times higher than that of activated carbon.

Activated carbon filtration

In this case, PFAS are adsorbed on the highly porous inner structure of activated carbon. The superior surface area of these sorbents is created via the high-temperature treatment (i.e., activation) of either coal or renewable feedstock-based chars. While being able to trap a broad array of PFAS within their pores, activated carbon’s adsorption performance increases with the contaminant chain length.

How to remove PFAS from wastewater via activated carbon

DESOTEC’s activated carbon filtration solutions were found to be a highly effective technology for removing PFAS from industrial wastewater, groundwater or firefighting wastewater.

Being able to work as a stand-alone technology makes activated carbon filtration more cost-efficient than the above mentioned techniques. This is particularly true when renting plug-and-play mobile filters rather than buying fixed installations upfront. Furthermore, activated carbon filtration can be upgraded to a closed-loop solution if the PFAS concentration on the activation carbon is below the POPs regulation thresholds and the activated carbon can be reactivated. Other benefits from mobile filtration are higher safety (i.e., pollutants are not handled on site), greater flexibility, and a minimal cost of ownership.

How to remove PFAS from air emissions via activated carbon

Unfortunately, PFAS can also sneak into your air emissions. Common examples include fabric coating, Which is why new regulations to control PFAS’ release are in the air too. Yet, you’re in luck. Our sustainable filtration solutions go beyond wastewater treatment. If you want to remove PFAS from your air emissions, DESOTEC can provide you with an ad-hoc activated carbon filter.

How to destroy PFAS in a law-proof & eco-friendly way

Although PFAS-containing products can be incinerated, their incineration is potentially bad for the environment as it doesn’t fully break down toxic compounds. To ensure full compliance with the stringent EU POPs regulation, in collaboration with VITO we’ve devised a validated method to accurately measure the level of PFAS adsorbed on activated carbon. If the PFAS concentration on the spent carbon is below the established and safe limits outlined in the European POPs Regulation, the saturated carbon will be subjected to a thermal reactivation process at our facilities. This route reactivates the carbon while breaking PFAS down completely and safely, thus avoiding their release in the environment. The absence of PFAS in the air was demonstrated by multiple measurement campaigns. However, when the PFAS concentration exceeds the EU POP limit, the activated carbon will not be reactivated on our site but will be transported to a specialised external party, ensuring safe and compliant treatment.

The end (of PFAS)

Countries around the world have already implemented strategies to reduce PFAS contamination risk. While POPs and other regulations are tightening PFAS emission limits, new purification technologies are popping up. After years of research and development, we have the expertise to select the most appropriate type of activated carbon and filters to optimise the purification of wastewater and air emissions containing a limited amount of PFAS. However, the design of a truly sustainable solution should go beyond the PFAS removal step and therefore companies have to offer a definitive yet green elimination of ‘forever chemicals’, considering the whole lifecycle of the purification technology. By using safe, law-compliant, and environmentally responsible technology, DESOTEC is helping the industry get rid of these chemicals, forever.