What are Per- and Polyfluoroalkyl Substances (PFAS)?
If you have not heard of PFAS (and if not, you soon will), this term refers to thousands of compounds created in the manufacturing of commercial products. These products include:
Aqueous film-forming foams (AFFF) for firefighting
Aid to polymerization
Mist suppressants in metal plating operations
The U.S. EPA and state regulatory agencies are taking a more critical look at PFAS and the associated health risks of PFAS accumulation in humans and animals. These risks could include disruption of fetal development and increased chances of certain cancers, immune system disorders, and fertility problems. It's likely a matter of time before Ohio regulates PFAS in drinking water, wastewater, and environmental media.
Why are PFAS So Hard to Treat and What Does that Mean in Ohio? The majority of full-scale PFAS treatment solutions are sorption processes (i.e., granular activated carbon and ion exchange) and/or separation processes (i.e., membrane filtration). While these are effective for specific PFAS at some sites, they also may be more expensive to maintain than other emerging technologies. Additionally, these solutions do not destroy, but only transfer these chemicals of concern to other media, which then need to be further dealt with by landfilling or incineration. Another concern is that some PFAS, especially the short-chain PFAS, don't like to associate with sorptive media or are too small to be effectively removed through membrane filtration making them particularly stubborn and hard to treat.
BREAKING IT DOWN: PFAS DESTRUCTION
An approach to successful treatment begins with understanding the chemical structure. PFAS by definition include at least one carbon that is fully saturated with fluoride; but usually there are several to a dozen or more forming a “backbone”. At the head of the backbone is a chemical functional group (usually containing carbon or sulfur). The carbon-fluoride bond is the strongest in organic chemistry (greater than 500 kJ/mol). Longer-chain and branched compounds contain many of these strong bonds and these outward-facing fluoride ions protect the PFAS carbon backbone, making it very resistant to traditional oxidation/reduction (electron transfer) and other chemical and biochemical reactions.
Think of the fluoride as a protective coating; similar to epoxy on steel which protects it from oxidation and reduction reactions (i.e., rust). The same reasons that make PFAS so good at repelling oils and grease also make it good at repelling chemical attacks. If the carbon backbone can be broken and the compound mineralized, it becomes a harmless combination of fluoride, carbon, oxygen and hydrogen atoms. The challenge is in breaking the bond, and the amount of energy required can become expensive.
THE GOOD NEWS
Innovative treatment technologies are just around the corner. Researchers are already looking into novel destruction technologies using electricity, sound waves to create highly-reactive chemicals that attack PFAS, plasma technologies, and special chemically-reducing species. Sorption and separation technologies are also being advanced by developing new ways to regenerate and reuse spent sorptive media and adding new functionality to existing membranes for better filtration. B&N is working to implement the cutting-edge ideas of our R&D partners' world-class research and development scientists to locate, treat, and monitor PFAS for utilities and manufacturers throughout Ohio. The goal of this partnership is to take a proactive approach to providing PFAS treatment solutions that are as effective as they are cost-effective. Join us in advancing the next wave of full-scale PFAS treatment solutions.