súz) West Lake Update
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November 7, 2014
EPA Begins Review of Isolation Barrier
Alternatives Assessment
EPA Region 7 recently received the isolation barrier
alternatives report from the Potentially Responsible
Parties (PRPs), and has begun to review its contents.
This report provides preliminary analysis of the pos-
sible isolation barrier alignments, including analysis of
bird control issues associated with each alignment.
In keeping with EPA's August 13, 2014, letter to the
Missouri Attorney General, copies of the report have
been provided to the U.S. Army Corps of Engineers
(USACE) and the St. Louis Airport Authority for their
review and evaluation concurrently with EPA. Each
agency plays an important role in this effort given the
technical complexities of the construction project and
the public safety concerns related to bird strikes.
The objective of the proposed isolation barrier is to
prevent potential impacts that could occur if a subsur-
face smoldering event (SSE) were to come into con-
tact with the buried radiologically impacted material
(RIM) in Operable Unit 1 (OU-1) of the West Lake
Landfill Superfund Site. Each evaluation looks at a
number of factors, including waste excavation and
relocation volume estimates, preliminary design and
construction schedules, potential for odor release, po-
tential to attract birds, potential risks associated with
each alternative, and potential advantages and disad-
vantages of each alternative.
A total of five alternatives were assessed, including
a "no action" alternative to provide a baseline assess-
ment. Not including the "no action" alternative, the
report details four potential alternatives, listed in the
report as Options 1-4:
Option 1 - Installation of an inert barrier located
along the northern boundary of the North
Quarry area of the Bridgeton Landfill/
southern boundary of Area 1;
Option 2 - Excavation of an air gap (open trench)
barrier down through the bottom of the
waste materials in the northern portion
of the North Quarry area of the Bridge-
ton Landfill;
Option 3 - Installation of an inert barrier located
within the northern portion of the North
Quarry area of the Bridgeton Landfill,
south of the currently identified known
occurrences of RIM;'
Option 4 - Installation of a heat extraction barrier
located along the southern portion of
Area 1/northern portion o! the North
Quarry area of the Bridgeton Landfill.
Hie report provides
an analysis of each
option, including
potential advantages
and disadvantages.
A comparative sum-
mary of the alterna-
tives and conclusions
is also included in the
The report is currently under review and evaluation
by various offices within EPA, as well as by our part-
ners at the USACE and the St. Louis Airport Author-
ity. If, after a robust engineering review and analysis,
no additional information is necessary to complete the
analysis of the preliminary alternative assessments,
EPA may then select one of the options and direct the
PRPs to further develop construction design plans.
EPA Region 7 appreciates and supports the work
of the Missouri Department of Natural Resources
(MDNR) and the State of Missouri, through its legal
orders, in directing Republic Services to monitor and
contain the SSE in the Bridgeton Landfill portion of
the West Lake Landfill Site. The additional tempera-
ture data and corrective action assessment recently
required by the MDNR will support both the states
efforts to monitor the SSE, as well as EPA and US-
ACE efforts to evaluate barrier alternatives. EPA is in
regular communication with MDNR about the depart-
ment's efforts to closely monitor the SSE. In partner-
ship with these organizations, EPA is working dili-
gently to develop a solution to address concerns about
the potential for a subsurface smoldering event (SSE)
coming into contact with the radiologically impacted
material (RIM) in the West Lake Landfill.
The Isolation Barrier Alternatives Assessment report
is currently available on EPA Region 7 s West Lake
Landfill website: www.epa.gov/region7/cleaiuip/west_
lake landfill
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