Upstate professor finds way to neutralize PFAS

Clarkson University scientists have been developing new ways to remove an especially toxic group of chemicals from industrial wastewater. This year, one of them won a national award for her research.

The chemicals are known as PFAS. They’re now in lots of everyday products and are dangerous to human health.

Selma Mededovic Thagard is a chemical engineering professor at Clarkson. She works on finding ways to remove toxins from wastewater using an electrical process. But when a colleague asked her to try it on PFAS-contaminated water her first reaction was, “What is PFAS?!”

PFAS is short for per-and poly-fluoroalkyl substances. The chemicals were used for decades before it was discovered they were dangerous.

“Firefighting foams, cosmetics, microwavable popcorn bags, Teflon,” Mededovic Thagard said. “I mean it’s pretty much everywhere. Everywhere.”

PFAS are even referred to as “everywhere” and “forever” chemicals. “Everywhere” includes the air and our bodies because PFAS are really good at making materials water, stain or grease-resistant. But they’ve been linked to kidney, liver and thyroid cancers along with other diseases.

Some companies dumped their contaminated wastewater into municipal sources for decades.

In the Rensselaer County village of Hoosick Falls, a 2014 investigation found that the municipal water supply contained high levels of some PFAS chemicals. Subsequent blood tests found that residents had high levels of toxins in their bodies.

Other studies concluded the village also has had higher than normal rates of some cancers likely caused by exposure to PFAS. The contamination is linked to industrial waste that was dumped into the nearby river for decades. It supplied the village’s drinking water.

Mededovic Thagard and a graduate student started by putting a small amount of PFAS-contaminated water through an electrical plasma generator. It worked.

“So, it’s nothing but an ionized gas. You’re shooting electrons through gas and, because they have such high speeds, velocities in the gas, they collide with molecules and turn them into plasma. They essentially ionize them,” she said.

It took over five years but Mededovic Thagard and the colleague who first brought the problem to her created a spin-off company. It now goes around de-contaminating industrial wastewater.

Mededovic Thagard said they use off-the-shelf materials to build the generators. And they use about as much wattage as a large microwave oven. They can even run on solar power.

“We’re on really, really large mobile trailers we have which can treat tens of gallons per minute of this contaminated water and we have been utilized by government agencies, by industrial clients to treat their PFAS-contaminated water,” she said. “So we are mobile, scalable and we are out there treating PFAS.”

Mededovic Thagard said it’s also effective at degrading PFAS in sludge or landfill runoff. So, it’s possible for farms to use this method to treat liquid manure fertilizers before they’re sprayed on fields.