A project to treat groundwater and soil contamination at the Marshall Center has attracted international attention and been added to a pilot program of the North Atlantic Treaty Organization (NATO). NATO is evaluating technologies that can be used where hazardous materials or their residues are present in the soil, subsoil and ground water.

A project to treat groundwater and soil contamination at NASA’s Marshall
Space Flight Center in Huntsville, Ala., has attracted international
attention and been added to a pilot program sponsored by the North Atlantic
Treaty Organization (NATO).

The NATO Committee on the Challenges of Modern Society has picked one
of the Marshall Center’s in-situ remediation projects as one of just
four worldwide for further study and evaluation.

The Marshall Center studies are evaluating various technologies that
can be used at locations where hazardous materials or their residues
are present in the soil, subsoil and ground water. In this case, the
focus is on removing chlorinated volatile organic compounds from soils
and ground water. This contamination occurred from former waste management
activities at the facility before the potentially harmful results of
such activities were known.

In 1994, the U.S. Environmental Protection Agency (EPA) placed the
Marshall Center on the National Priorities List of sites eligible for
cleanup under the Superfund, an environmental program managed by the
EPA to clean up hazardous waste sites throughout the United States.
The Marshall Center studies are part of a process to identify, investigate,
sample and restore 67 sites at Marshall where hazardous material was
used. Since 1994, the Marshall Center has spent an estimated $24 million
on identifying, investigating, sampling and restoring the sites.

The project selected by the NATO committee involves injection into
the ground of zero-valent iron powder — small solid iron particles
— in slurry form using the Ferox sm process patented
by ARS Technologies Inc., of Highland Park, N.J., an environmental engineering

These chemical reduction pilot tests are to be conducted beneath two
contaminated areas and are directed primarily at the treatment of trichloroethene,
a solvent that was used to clean rocket engines, in the sub-surface
soil and water. Investigations indicate that there are man-made chemicals,
like these solvents, still present in the water. These types of contaminants
are heavier than water and will keep moving through the subsurface until
they find a resting spot. Along the way they can also leave small deposits
at various depths, a result referred to as residual contamination.

The Marshall Center’s Environmental Engineering Department developed
nad and implemented the remediation project in collaboration with CH2M HILL,
an international consulting engineering and project delivery firm headquartered
in Greenwood Village, Colo.

The study’s focus is on treatment of naturally oxygenated, contaminated
groundwater within an interval area called the rubble zone — a
transitional area between the clay soil and the limestone bedrock —
as well as on treatment of the clay soil above the rubble zone where
there is a significant amount of contamination.

In one area, designated SA-2, trichloroethene groundwater contamination
was as high as 70 milligrams per liter. The federal standard for allowable
groundwater contamination of this substance is .005 milligrams per liter.

The SA-2 site is in a test area where in the 60’s and 70’s rocket engine
parts were routinely cleaned following tests. Unexploded ordnance remaining
from the World War II era was also present in the area, eliminating
the simpler option of doing a general treatment of the entire contaminated
area. Therefore, the approach taken was to inject zero-valent iron powder
where possible in the most contaminated areas. Then overlapping injections
were inserted into areas where water would naturally flow, creating
a treatment zone for untreated water to flow through. Monitoring of
the area after the injections showed contaminant concentrations in the
affected area were reduced by more than 90 percent.

Monitoring results at another site, called SA-12, near a building where
routine cleaning and degreasing of parts occurred (during development
of the U.S. space program) were not as encouraging.  Much higher levels
of contamination than anticipated were found in this area that contains
trichloroethene with some perchloroethene and Freon in both saturated
and unsaturated zones.

During the first tests unexpectedly high SA-12 trichloroethene concentrations
— approximately 350 milligrams per liter in the groundwater and
46 milligrams per kilogram in the unsaturated zone — were encountered.
The zero-valent iron powder injection was used for this area because
of the groundwater depth and the presence of underground utilities in
the area.

It was determined that not enough of the slurry was injected for the
conditions being encountered. Therefore, follow-up laboratory tests
were conducted to re-assess the use of the zero-valent iron powder slurry
injections. Results indicate that the conditions at SA-12 are potentially
treatable with this approach. However, other types of treatment are
also under consideration.

Additional information about the project can be obtained from Amy Keith,
a Marshall Space Flight Center environmental engineer, (256) 544-7434,
by e-mail: Amy.Keith@msfc.nasa.gov or from Bill
McElroy, project manager, at CH2M HILL, (352) 335-7991, or by e-mail:

To learn more about the technology, visit the ARS Technologies Web
site at: http://www.arstechnologies.com.