Per- and Polyfluoroalkyl substances, PFAS, are highly toxic chemicals used in industrial applications around the world. This family of chemicals, also known as forever chemicals, are commonly found in the foam used to combat airfield fires. In an edition of the AviationPros podcast, Rosa Gwinn, global PFAS technical leader for AECOM, and Scott Wilson, CEO and president of REGENESIS, join AviationPros assistant editor Walker Jaroch to discuss how PFAS harm the environment and what can be done to remediate it.
The Department of Defense adopted PFAS as the standard for firefighting use in the 1960s and the FAA followed in the 1970s, according to Gwinn. PFAS are resistant to chemical, biological and thermal degradation; firefighters add the chemicals to water to put out fires more effectively. The compounds create a foam that sits on top of oil, putting out the fire faster and reducing the chance for burn back. PFAS compounds are used all around the world, but why is that a bad thing?
Gwinn explained PFAS compounds are bioaccumulative, which means as they travel up the food chain, they become more prevalent in an organism’s body. PFAS can mix with water and trickle down into the water table, which makes it a hazard for wildlife and humans.
PFAS are a toxic chemical even in low concentrations; The EPA says water must have less than 70 parts per trillion PFAS to be safe for consumption. Wilson said “this is like a thimbleful in Olympic swimming pools,” making PFAS remediation difficult, but not impossible.
“What we’ve done is we’ve developed an advanced technology where we take a coconut fiber charcoal and we mill it down to the size of a red blood cell so it looks like black ink," Wilson said. "And we actually pour that into the aquifer, into the subsurface through wells where it coats the entire aquifer surface that’s impacted with this charcoal. And the result is that it strips all the PFAS out of the water and onto the aquifer matrix itself, locking it up. We lock the PFAS up, it doesn’t migrate in the groundwater anymore.”
“The [contaminated] water will flow downhill and the concern here is that if there’s a fire training area that used PFAS, the groundwater and soil beneath is impacted. Over time, it migrates off the facility in what’s called a plume,” Wilson noted.
“The way that remediation has traditionally been carried out is environmental engineering firms move out a bit of the field and try to capture that plume by putting in wells and pumping the polluted water to the surface. And then filtering out the PFAS and the concern here is the huge cost of putting in wells and pumping that water to get down to really low levels,” he continued.
The coconut fiber charcoal process was used on 16 sites around the world and is currently being approved for use in 100 other projects, Wilson said. This approach should “lock up” the PFAS for 30-50 years with a single injection. If there is an additional spill or another contamination, environmental agencies can add another injection to renew the barrier.
To listen to the entire podcast, click the link. AviationPros.com/21215052
