Fairbanks incinerator shows promise for cleaning toxic soil

Published: Oct. 8, 2019 at 9:23 PM AKDT
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A pilot project in interior Alaska is being closely watched by the Environmental Protection Agency for its effectiveness is cleaning toxic soil. In a first-of-its kind effort, NRC Alaska is home to the nation's only incinerator permitted for destroying per- and polyfluoralkyl substances, commonly known as PFAS.

The human-made, toxic compounds have been widely used since the 1940s, and are now known to be persistent in the environment and the human body.

Alaska is increasingly detecting contaminated groundwater linked to PFAS contamination from fire-fighting foams containing AFFF, used at airports and military installations. Other known sources of PFAS include some food packaging, stain- and water-repellent fabrics, and teflon-coated cooking pans.

The NRC incineration project, approved with a permit from the Alaska Department of Conservation, started commercial operation in March.

"Our technology is the only technology right now that is known to handle and destroy PFAS," Mark Sanford, General Manager of the thermal remediation facility for NRC Alaska told KTUU Tuesday.

The kiln processing contaminated soil by first heat-cleaning the soil, then using additional high-temperature processes and filters to control post-combustion emissions.

"So the dirt's completely clean, and we're destroying anything that's coming off the dirt," he said.

Sanders said tests have shown that if the incinerator processed PFAS soils every hour of every day for a year, less than one-one-hundredth of a pound of PFAS would accumulate in the smokestack.

Jason Brune, Commissioner for the Alaska Department of Environmental Convesation, confirmed tests showed "almost complete thermal destruciton" -- that is, "0.0015 pounds of PFAS chemicals will, if operated on an annual basis, will come out of the stack."

Still, in a recently published technical brief, the EPA acknowledges that "the effectiveness of incineration to destroy PFAS compounds and the tendency for formation of fluorinated or mixed halogenated organic byproducts is not well understood."

Insufficient temperatures, time, and mixing can yield less than ideal results, causing what is known as products of incomplete combustion, according to the EPA.

Citizen watchdog groups have concerns about the ability of the incinerator to eliminate PFAS and worry it could be a mechanism through which the contaminant becomes airborne.

"We haven't seen the official report. We haven't seen the conditions under which the testing was done specifically. We don't know where exactly the soils were collected for the test. Those things may all be in a report, but the ADEC and the EPA are going to have to do a better job at helping the public understand why this isn't a threat to us in any way," Patrice Lee, with the groups Citizens for Clean Air and a WATER (Wake Up Alaskans to the Toxic Environmental Reality), told KTUU.

Fairbanks is already a region with poor air quality, and green-lighting a project that could increase emissions doesn't seem wise, she said.

Sanford told KTUU the plant wouldn't run over the winter when air quality worsens. And Brune said us, he and his staff had the same concerns. Cleaning soil to simply redistribute a toxin through an air plume was not an outcome ADEC would have signed off on, he said.

"This is a test that the nation is watching. Indeed the world is watching. 'How are we going to address these contaminated soils?' And we're on the leading edge of trying to address it. So while I know there is a concern that we are potentially creating issues down the air shed, that's the whole reason why we're studying this because we want to make sure we're not," Brune said.

Sanford said he, too, had concerns. His neighbors, family members, and coworkers are all within the groundwater plume from the Moose Creek PFAS exposure, so cleaning up -- not making things worse -- was a priority, he said.

The company has spent nearly $750,000 in upgrades to handle PFAS incineration and is so far pleased with the results.

"We were able to destroy it at the higher temperatures. That's how we're volatilizing it out of the soils; then the gasses go into the secondary (thermal treatment), which range anywhere from 1,850 degrees (Fahrenheit) up to 2,300 degrees. That's where we fry any gases that are coming off of it," Sanford said.

Before emissions are released into the stack, they are funneled through a quench tower, baghouses, and a type of filter known as a wet scrubber.

Brune said Eileson Air Force Base has previously contemplated exporting contaminated soils to Oregon, at the cost of millions of dollars -- a solution he and his staff didn't support. Incineration, if it works, could be a workable alternative.

"There's a lot of the soil that's going to ultimately have to be remediated in Alaska, and indeed around the world, and we have to figure out what we're going to do about it. This is a proactive approach that the state is taking to try to have a local solution for a local problem," Brune said.

The EPA will travel to Alaska next week to perform tests at the NRC facility and assess how good of a job it's doing cleaning soils and keeping PFAS out of the air.

Lee wants greater transparency, to be assured of the integrity of the process and the test results, which she wants made public.

"We need to have it explained in a way that assures us that we are not going to suffer additional harm by breathing the air where we live," Lee said.