[CPEO-MEF] Phytoremediation at Fairchild AFB (WA)

[Lenny Siegel <lsiegel@cpeo.org>]

Fairchild tests environmental cleanup process 

by Master Sgt. Scott King 92nd Air Refueling Wing Public Affairs
Air Force Link
January 19, 2005

FAIRCHILD AIR FORCE BASE, Wash. (AFPN)  -- The base here encompasses
536,028 acres, all of which the Air Force is mandated by federal law to
protect and conserve through effective environmental planning and management.

As part of this effort, there is a one-acre site where 1,130 hybrid
poplar trees were planted; a drip irrigation system was installed along
with monitoring equipment to evaluate a potential cleanup technology
that can be used with shallow contaminated groundwater. 

The site, located in an open field, is a phytoremediation demonstration
project being conducted by officials from the 92nd Civil Engineer
Squadron's environmental flight, the Air Force Center for Environmental
Excellence's environmental science division and a global engineering
firm. 

"Phytoremediation is the use of plants to remove, degrade or contain
pollutants in contaminated soil or groundwater," said Amber Brenzikofer,
a principal scientist with the firm. "One application of
phytoremediation is phytostabilization where we use the trees as
'groundwater pumps' when roots reach a depth where they can draw
moisture from the water table."

The trees act as an extraction well removing contaminated groundwater by
giving off vapor-containing waste by-products through the pores of plant
tissue, possibly minimizing migration of contaminants, officials said.

In some locations, poplar trees can process between 50 to 300 gallons of
water per day. This amount of water extraction can be an effective
hydraulic control on the flow of subsurface water, officials said. 

"The shallow groundwater, which is 10 to 12 feet below the ground
surface, is contaminated with chlorinated solvents; mainly
trichloroethene," Ms. Brenzikofer said. "Chlorinated solvents ... are
among the most common soil and groundwater contaminants."

Lengthy and careful planning has gone into this demonstration, right
down to the type of trees planted.

"The hybrid poplar trees were selected because of their fast growth rate
and ability to take up large amounts of groundwater when fully grown.
Now in their fourth growing season, some of the trees have reached 15 to
40 feet tall," she said. "It has been shown that once poplar trees have
taken up chlorinated solvents in their tissues, they can oxidize it into
(nonhazardous materials)."

Officials at the 92nd CES have been working hand-in-hand with the center
and the firm on the four-year long project. 

Some of the advantages of the project are that it's "very green,"
aesthetically pleasing, less expensive to build than other remediation
alternatives and requires less preparation and maintenance funds,
officials said.

The construction cost of the demonstration was $23,000. Annually, it
costs between $30,000 to 50,000. It is funded by the center.

It is very economical compared to other treatments such as a small pump
and treat system where construction costs alone can reach $3 million;
however, the demonstration has yet to be proven as a 100 percent
reliable technology, officials said. 

"(The) technology is slower than other treatment processes, so it may
take years to produce definitive results," said Marc Connally,
environmental restoration programs chief for the 92nd CES. 

Information and data for the study will continue to be collected, and a
final report will be prepared later in the year, he said. 

"We think this technology has a strong chance of being part of the final
remedy to cleanup this site and has the potential to be applied to other
Air Force bases as well as to cleanup groundwater contamination at
commercial industrial sites across the nation -- you can't have a better
test-drive than that," he said.

For the original press release, see
http://www.af.mil/news/story.asp?storyID=123009640

-- 


Lenny Siegel
Director, Center for Public Environmental Oversight
c/o PSC, 278-A Hope St., Mountain View, CA 94041
Voice: 650/961-8918 or 650/969-1545
Fax: 650/961-8918
<lsiegel@cpeo.org>
http://www.cpeo.org
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