PFAS Re-Foamed: A Treatment Breakthrough

Right now, scientists are working on treatment strategies that will not just reduce PFAS concen­tra­tions, but destroy any traces of the chemicals. As states continue to reduce acceptable PFAS exposure to nearly non-detect levels, research and development of destruction strategies has only become more important. Known as a “treatment train,” these solutions usually involve three stages: Separate. Concentrate. Destroy. One of the more promising ways to separate PFAS  involves leveraging a naturally occurring phenomenon called foam frac­tion­a­tion. 

Under certain conditions, proteins, detergents and fluorosurfactants (like PFAS) can collide with pockets of air, which carry them toward the surface and collec­tively form bubbles or foam. The right conditions can be as simple as pouring a beer. Carbon dioxide carries proteins formed during the fermen­ta­tion process to the top of the glass, giving it it’s unique foam “head.” But the foam frac­tion­a­tion process also holds great potential to effectively separate PFAS, and ultimately destroy it. Due to the surfactant nature of PFAS compounds, which makes them partic­u­larly well-suited to foaming, re-foamed PFAS has been observed in cont­a­m­i­nated lakes and rivers. And, during the wastewater and landfill treatment processes, it is not uncommon to generate a layer of foam from naturally occurring sources and organic surfactants.  

CDM Smith researchers like Dr. Charles Schaefer have observed PFAS uptake at air-water interfaces—in other words, foam—and have developed PFAS air-water interface parti­tion­ing coef­fi­cients. While PFAS-specific treatment tech­nolo­gies applicable for landfill leachate and wastewater treatment plants are still under development, the PFAS uptake phenomenon by air-water interface (i.e., foam) may allow the foam to be properly skimmed off and collected.  

This process, known as foam frac­tion­a­tion, has been studied using PFAS-impacted landfill leachate in recent months. The treatment appears to be highly effective for all but the smallest and largest PFAS molecules. There is the potential to apply foam frac­tion­a­tion at wastewater reclamation facilities, in-situ groundwater remediation sites, and to treat RO concentrate and inves­ti­ga­tion-derived wastes.