Harmful compound is found almost everywhere
University of Rhode Island hydrogeologist Thomas Boving and colleagues at
EnChem Engineering Inc. are testing a proprietary new technology for quickly
removing and destroying hazardous chemical compounds from soil and groundwater. 
The PFAS compounds extracted from the ground are destroyed using
an ultraviolet light technology inside this trailer.
(Photo courtesy of EnChem Engineering Inc.)
If proven effective, the technology could soon be applied to cleaning up the
abundant per- and polyfluoroalkyl substances, collectively referred to as PFAS
and “forever chemicals,” that contaminate drinking water supplies serving about
one-third of Americans.
PFAS compounds have been in use for
more than 60 years and are found in common household goods like non-stick
cookware, stain-proof carpets and pizza boxes, as well as in firefighting foams
and other industrial products. Because they do not break down easily in the
environment, they find their way into human and animal tissues and can lead to
many serious diseases.
“Our approach to this problem is in two steps,” said Boving, URI professor of geosciences and civil engineering. “First, we flush the compounds out of the ground by pumping in a sugar molecule that has the ability to remove PFAS from the soil and groundwater. Then we pump the solution out of the ground and hit it with a chemical oxidation process to destroy the compounds.”
The process was developed in
collaboration with Raymond Ball, principal of EnChem Engineering in Newton,
Massachusetts, a hazardous waste site remediation company that used an earlier
version of the technology to remediate mixed organic wastes at an Air Force
base.
“When we detected PFAS during that
project, it was proposed that we do a follow-on study for the treatment of
PFAS, and that’s what we’re doing now,” said Ball.
The refined technology, called XCT
OxyZone, is being tested this winter at Joint Base Cape Cod, a military base
formerly known as Otis Air Force Base, where firefighting foams used at its
former fire training center contaminated groundwater in the region with PFAS.
The scientists are drilling injection wells and extraction wells at the site
this month and will begin testing the process in January.
“We’ll inject the solution for three
or four hours, then extract it for about the same amount of time, then repeat
the cycle,” said Boving. “It’s like putting the soil through the washer for
repeated cycles, but without first excavating it. And if all works as we
expect, within three or four months we’ll have achieved our goal of reducing
PFAS contamination to levels that meet Massachusetts pollution guidelines.”
Once the contaminants have been pumped
out of the soil and groundwater, they are processed using an ultraviolet light
technology that breaks the chemicals into their basic elements. That process is
done inside a 40-foot steel container that can be transported to other
contaminated sites as needed.
According to Ball, the only
alternative currently available for cleaning up sites contaminated with PFAS is
to dig up the soil and wash it in special machines, but it is very expensive
and impractical, especially where the chemicals have penetrated deep below the
surface.
“When you leave the PFAS in the
ground, it travels with the groundwater, contaminating the groundwater
downstream forever,” Ball said. “The faster you can clean up the source area,
the better. And our process is fast.”
In addition to remediating sites
contaminated with PFAS, Ball said the technology can also be applied to
cleaning up a wide variety of other contaminants, including chlorinated and
petroleum-based compounds.
“We likely have the only technology
for remediating PFAS that is working at this scale at this time,” said Boving.
“There are a lot of other great ideas out there, but most are still being
tested in the lab. We’re ahead of the game, and we have high hopes.”
The testing is funded in part by the
National Institute of Environmental Health Sciences.