This story is a product of Mississippi River Basin Bureau of Agriculture and Wateran editorially independent reporting network based in University of Missouri School of Journalism in partnership with Report for America and the Society of Environmental Journalistsfunded by the Walton Family Foundation.
How to destroy a pollution so tenacious that it is nicknamed “eternally chemical”?
It’s a question researchers and companies across the country are eager to answer, as regulations tighten on PFAS, or per- and polyfluoroalkyl substances, and chemical producers face a mountain of chases.
The chemicals are found in fast food wrappers, fire-fighting foams, non-stick cookware and dental floss. They don’t break down easily in the environment, they flow easily with water, and research has linked them to health effects such as immune and fertility problems and certain cancers.
Getting rid of harmful chemicals is “a multi-billion dollar elephant ahead of us,” said Corey Theriault, a technical expert specializing in dealing with PFAS at engineering and consulting firm Arcadis.
PFAS have been destroyed by incineration, but there are questions about how combustion works, and the Department of Defense has ended the practice of burning these chemicals. Last year.
Everyone from municipal water providers to Fortune-100 companies has shown interest in the technologies, Theriault said. The US Army Corps of Engineers is offering a contract to handle, destroy and replace PFAS-rich fire-fighting foam, worth about $800 million, according to the government’s tender document.
PFAS have become so popular in consumer goods because of the durable carbon-fluorine bond that makes up the bonds in the “short chain” and “long chain” versions of the chemicals. These bonds help repel stains, water and grease, and cut off oxygen to dangerous flames.
But this chemical bond is also extremely difficult to break.
Many methods currently being tested for PFAS removal have often been used in other chemical cleanings. Engineers attempt to pop molecules in modified pressure cookers; split them with UV light and energized additives; breaking PFAS chains with electricity, or separating atoms with cold plasma, a charged and reactive gas.
Minnesota Pollution Control Agency
No technologies are yet in wide-scale deployment, but Theriault said those that are furthest along in development could be ready within the next six to 18 months.
However, none of these technologies will directly treat a contaminated water source. First, the water should be filtered so that the PFAS ends up in a concentrate that is more cost effective to treat because there are more chemicals in each gallon. The State of Minnesota already uses a machine that sucks PFAS from contaminated groundwater in by repeatedly stirring groundwater into a frothwhere chemicals tend to accumulate.
“The cost per volume of liquid to process for these destructive approaches is much higher,” said Timothy Strathmann, professor of civil and environmental engineering at the Colorado School of Mines. He developed a method of destruction called alkaline hydrothermal treatment or HALT, which he described as “a steroid pressure cooker”.
The need for a concentrated chemical soup to experiment with has led at least a dozen companies to showcase their products in Minnesota because the state is already creating it with its filter machine, said Drew Tarara, geologist and program manager at AECOM.
“It feels like everyone is trying to get their foot in the door,” Tarara said.
Minnesota partners with AECOM to investigate new PFAS technologies. The first six months of this pilot study cost $500,000, Minnesota Pollution Control Agency spokeswoman Andrea Cournoyer wrote in an email.
Minnesota will then use the De-Fluoro system, an electrochemical approach marketed by AECOM, to attempt to destroy the PFAS in its frothy concentrate.
The state has faced a decades-long PFAS contamination problem in the eastern part of the Twin Cities where Maplewood-based 3M, one of the original developers and manufacturers of PFAS, polluted groundwater with landfills and leaky disposal sites. Money from a lawsuit the state settled with 3M in 2018 is paying for the work being done today with AECOM.
3M recently announced that it stop using the chemicals in its products by 2025. But the challenge of clean up what has already escaped into the environment remains.
The De-Fluoro unit is “still very extensively field tested,” Tarara said. The unit will be tested at the Washington County landfill for up to six weeks, where it will process PFAS concentrate collected by the state, but Tarara and state officials were cautious in describing what the De -Fluoro can do. Rebecca Higgins, senior hydrogeologist at MPCA, previously told the Star Tribune that De-Fluoro may only be able to break long-chain PFAS into shorter segments rather than destroying them.
State officials have also said they want to test other technologies. Cournoyer wrote that any additional systems would be selected according to state procurement rules, and officials will also search the scientific literature for reports of other technologies.
But the world of PFAS destruction is rife with proprietary methods and nondisclosure agreements, making it difficult to gauge what actually works. A notable exception is a study published in the journal Science last year, where researchers boiled the chemicals with two other compounds over low heat. But the method is still in laboratory testing.
Companies like Claros Technologies, a Minnesota-based startup, typically don’t know who exactly owns the PFAS waste they’re experimenting on because those partners may have legal liabilities. It is therefore difficult to validate the results announced by the company: 99.9% to 99.99% destruction of PFAS when treated with UV light and an additive.
Shari L. Gross, Star Tribune
These tests for Claros are also not verified in peer-reviewed scientific journals, as the process is proprietary.
John Brockgreitens, director of research and development for Claros, said the company hopes to one day process tens of thousands of gallons of liquid per day. But he admitted it’s difficult to answer detailed questions about the results of the company’s photochemical method.
“We talk to teams of scientists and they ask us the same thing,” he said. “Walking this line is a challenge.”
Theriault, who said his company remains “agnostic” about the technologies it recommends to its customers, said Arcadis has partnered with Claros and their method “definitely showed promise” to be useful in more applications than some other methods.
“There’s no single technology that’s going to crush it on every level,” Theriault said.
But for communities dealing with pollution, the technologies can’t come soon enough, because current waste treatment methods don’t contain the chemicals.
“Any landfill will fail, no matter how constructed,” said Rainer Lohmann, director of the University of Rhode Island’s STEEP Laboratory and an authority on PFAS contamination.
Many landfills no longer accept waste known to be contaminated with PFAS, sources said.
And until a regulatory body like the Environmental Protection Agency sets standards for how PFAS should be destroyed, there is no official benchmark for new technologies, said Lohmann.
“Does it destroy 95%? 99%? What do you do with the rest? said Lohmann.
