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Annual Site Environmental Report for 1999
• Completed installation and began
operation of the Lasagna technology
as the selected remedial alternative for
reducing the concentration of TCE in
SWMU 91.
• Submitted the Remedial Investigation
~RI)IFS Work Plan for the Surface Water
Operable Unit to the regulators for
review and comment.
• Performed the WAG 28 and WAG 3
RIs, the WAG 8 Site Evaluation (SE),
and the Data Gaps Investigation.
Information concerning these four
activities is summarized in the following
text.
Lasagna
In July 1998, DOE issued the Record of
Decision for Remedial Action at Solid Waste
Management Unit 91 of Waste Area Group 27 at
the Paducah Gaseous Diffusion Plant, Paducah,
Kentucky (DOE 1998). The Record of Decision
(ROD) designated Lasagna as the selected
remedial alternative for reducing the
concentration of TCE in SWMU 91 to levels that
would decrease the potential groundwater risk to
human health and the environment at the pointof-exposure
(POE).
Lasagna was selected as the preferred
remedial alternative for the reduction of TCE in
the soil at SWMU 91. The ROD states, ''The
primary objective of this remedial action is to
reduce the level of TeE-contaminated soil,
thereby reducing the potential future
concentrations in groundwater that could pose a
threat to human health and the environment' at
the POE (ii.e.,. theJ!)OE property boundary)."
The Lasagnasystem willibe operated for two
years in an,attempt to reduce the concentration of
TCE in SWMU 911 soil from an average of84 mg!
kg to an average of less than 5.6 mgtkg. If after
two years the regulatory approved cleanup level
of 5.6 mglkg has not b,eenachieved, the system
may operate an additional 12 months to achieve
the cleanup levels.
Lasagna uses an applied direct current
electric field to drive TCE-contaminated
groundwater through treatment zones installed
in the contaminated soil. This induced
groundwater flow is called electro-osmosis. The
groundwater flow induced by the direct current
travels from the anode electrodes to the cathode
electrode. Groundwater containing TCE is
driven away from anode electrodes toward the
cathode electrode and' passes through a series of
iron particle treatment zones installed between
them. The TCE is broken down into
nonhazardous compounds as it comes in contact
with the iron particles in the treatment zones.
Additional information about the Lasagna
technology and its development can be found in
the Final Soil Characterization Work Plan For
The Paducah Gaseous Diffusion Plant Lasagna
Pilot Test In The Cylinder Drop Test Area
(MMES 1994) and the DNAPL Site
Characterization And Lasagna Technology
Demonstration At Solid Waste Management Unit
91 Of The Paducah Gaseous Diffusion Plant;
Kentucky (LMES 1996a).
Anode electrode zones were installed
generally north to south along the outer edges of
the 90-ft wide treatment area. The cathode
electrode zones were installed generally north to
south in the middle of the treatment area. The
direct current to energize the electrodes comes
from a rectifier that is fed from a 480-volt
alternating current supply constructed for this
project. New overhead electrical utility lines,
power transformers, electrical switching center,
and associated accessories provide power to the
Lasagna site. In general, treatment zones were
installed at 5-ft intervals across the treatment
area. However, treatment zones were installed at
25-ft intervals in higher concentration regions
of the treatment area~ When possible, electrode
and ,treatment zones were installed to a depth of
45 ft. iPlumbing was installed to recycle treated
water from the cathode back to the anodes.
Installation of the Lasagna technology
was completed in September 1999. The system
is currently operational and is being monitoring
for progress of remediation of SWMU 91.
Environmental Program Information
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