Momentum

Furniture and carpets, cosmetics, outdoor gear and building materials might not last forever, but some substances found in them seem to. Per- and polyfluoroalkyl — more commonly known as PFAS — are human-made chemicals prevalent in a wide variety of commercial and consumer goods.

The problem is that these chemicals are toxic, and any runoff from the use of PFAS-based products leaches through the soil into the groundwater, said Takahiro Yamada, principal environmental chemist in the University of Dayton Research Institute’s energy and power division.

"PFAS tend to be highly concentrated near locations where firefighting foam is used, but they have also been found in the air, water and soil virtually everywhere around the globe," he said.

Compounding the problem is that the strong chemical bond that gives PFAS their appealing qualities for products also make them incredibly durable. They can last thousands of years, don't degrade naturally in the environment and measures to destroy them have remained elusive — earning them a spot in the notorious list of "forever chemicals," Yamada added.

The U.S Environmental Protection Agency, U.S. Department of Defense and other organizations have been pursuing remediation solutions for a number of years because of the impact of PFAS on the environment and human health, Yamada explained. But investigating PFAS destruction techniques has been challenging because of the vast number of substances; the CDC reports more than 9,000.

Working under a variety of federal and industry funding sources, however, Yamada and his colleagues have made important progress in determining the best conditions to completely destroy PFAS. Using a laboratory-scale incinerator, the researchers have tested a variety of heating techniques designed to break down the carbon-fluorine bonds responsible for PFAS' robustness.

"Based on our research, we've been able to suggest the optimum conditions to completely destroy PFAS under various conditions." 

The researchers are collaborating with the EPA to determine whether their test results are consistent with those of tests performed by the EPA using a pilot-scale incinerator. 

UDRI is currently funded by the EPA, directly as well as through a DOD-sourced EPA Strategic Environmental Research and Development Program. In addition to PFAS-destruction studies, the EPA is funding a program at UDRI to investigate the potential impact of burning PFAS-laden biosolids produced at wastewater treatment facilities.

"Once PFAS gets into the ground water, it spreads to rivers, oceans and drinking water, which means it also gets into wastewater," Yamada said. "The process of wastewater treatment generates biosolids, which can be dried and incinerated to reduce volume or to produce electricity. The concern is whether burning PFAS-laden biosolids will release the PFAS into the atmosphere."

UDRI researchers are also studying PFAS destruction in a separate program funded by the semiconductor industry. Yamada said PFAS containing organic solvents are used in the production and cleaning of semiconductors, and the chemicals are then collected and incinerated to treat PFAS. Industry funders want to understand whether the current burning process is sufficient to destroy the PFAS.

"Under these studies, we've been able to provide information to organizations that deal with PFAS on steps they can take to modify their systems or processes to help keep these substances out of the environment."