United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R04-92/108
June 1992
S-EPA Superfund
Record of Decision:
Savannah River (USDOE)
(Operable Unit 1),SC
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NOTICE
The appendices listed In 1M Index that are not found In this document have been removed at tINt request of
the issuing agency. They confajn maf8riaJ which ~ but 8dd8 no fuIth8r IppIic8b1e Information to
the content of the document. All ~ material is, however, c:ontained In the administrative record
tor this site.
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50272.10'1
REPORT DOCUMENTATION 11' REPORT NO. 1 ~ 3. Reclplent'e Ac:C888lon No.
PAGE EPA/ROD/R04-92/108
4. TItI8 end Subtitle S. Raport 0.18
SUPERFUND RECORD OF DECISION 06/29./92
Savannah River (USDOE) .(Operable Unit 1), SC
6.
First Remedial Action
7. Authot(e) 8. "donning Orgenlzatlon RepL No.
8. "donning Orgelnlzatlon Name end Add.... 10. ProjectlT88klWo,k Unit No.
11. Contrec1{C) 0' Gtent(G) No.
(C)
(G)
1~ SpoMoring Otgenlzatlon Name end Add.... 13. Type 01 Raport & ..,loci Cowr8d
U.S. Environmental Protection Agency 800/000
401 M Street, S.W.
Washington, D.C. 20460 14.
1 S. Supplemenl8ry Notee
PB93-964023
16. Abetrect (Umlt: 200 worde)
The 300-square-mile Savannah River site (SRS) is a Department of Energy (DOE) facility
located in Aiken, Barnwell, and Allendale Counties, South Carolina, 20 miles south of
Aiken, South Carolina, and 25 miles southeast of Augusta, Georgia. Land use in the
surrounding area is primarily agricultural. The Savannah River Site is a secured
facility with no residents. The site, co-operated by the Westinghouse Savannah River
Company, is a national defense-related facility producing tritium, plutonium, and
other special nuclear materials. From 1958 to 1985, SRS used a northwest portion of
the site, termed the "M-area, " as a hazardous waste management facility (HWMF). The
M-area HWMF or OU1 consisted of an unlined surface impoundment (settling basin), a
process sewer line, an overflow drainage/seepage area, and an area known as Lost Lake,
which represents a special ecological environment known as Carolina Bay.
Manufacturing wastes from aluminum-forming and metal-finishing operations conducted
onsite were discharged through the sewer line to the basin, where metals such as
uranium, nickel, lead, and aluminum settled out of solution. Any basin overflow went
to the drainage/seepage area and then on to Lost Lake. Use of this system ended in
1985, when a new wastewater treatment facility was installed. This interim ROD
(See Attached Page)
17. Document AnaIy8J8 L DeecriptOl8
Record of Decision - Savannah River USDOE) (Operable Unit 1), SC
First Remedial Action - Final
Contaminated Media: soil, sludge, sw
Key Contaminants: VOCs (PCE, TCE), metals (lead), acids, radioactive materials
b. Ic8nIlfl8NlOpen-End Tenne (uranium)
c. COSA11 FleldlGroup
18. A_lIebillty Ste_t 18. Secu,1ty CIe88 (Thie Raport) 21. No. of Pegee
None 34
20. Security CIe88 (Thle Page) 22. PrIce
None
AHSI-Z38.1. s.. IMtructJOM on Reve,.. 272'''''1
(See
(Formerly ~)
Dep8l\m8nt of Commerce
.'
-------
EPA/ROD/R04-92/108
Savannah River (USDOE)
First Remedial Action
(Operable Unit 1), SC
Abstract (Continued)
integrates previously completed RCRA closure activities that were required and approved
by the South Carolina Department of Health and Environmental Control. Future RODs will
address final remedial actions for other contaminated media, including the vadose zone
and ground water, associated with the M-area HWMF. The primary contaminants of concern
affecting soil, sludge, and surface water are VOCs, including TCE and PCE; metals,
including lead; acids; and radioactive materials, including uranium.
The selected remedial action for this site includes pumping and onsite treatment of any
standing water that remained in the basin; excavating, dewatering, and stabilizing
approximately 37,000 cubic yards of basin sludge using Portland cement; placing,
consolidating, and compacting the stabilized sludge into the basin; discharging the
sludge effluent from the dewatering process offsite to a permitted NPDES outfall;
consolidating approximately 39,700 cubic yards of contaminated soil excavated from the
seepage area, Lost Lake, and a portion of the sewer line into the basin; installing and
maintaining a low permeability cap over the settling basin, which includes a surface soil
layer that will be graded and vegetated to promote drainage; monitoring ground water; and
implementing institutional controls including deed restrictions. The estimated present
worth cost for this remedial action ranges from $3,000,000 to $5,000,000, which includes
an annual O&M cost of $20,000 for 30 years.
PERFORMANCE STANDARDS OR GOALS:
No chemical-specific clean-up goals were provided in this interim ROD, but will be
provided for the final M-area HWMF remedial action. The goal of this interim ROD is to
integrate prior RCRA decisions into the CERCLA process. The goal of the remediation is
to minimize the migration of contaminants to the ground water and eliminate surface
transport pathways.
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WSRC-RP-92-743
INTERIM ACTION RECORD OF DECISION
REMEDIAL AL TERNA TIVE SELECTION
M-Area Hazardous Waste Management Facility Operable Unit
Savannah River Site (0. (A.. I )
Aiken County, South Carolb;a
Prepared by:
U.S. Department of Energy
Savannah River Field Office
Aiken, South Carolina
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INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
DECLARATION FOR THE INTERIM ACTION RECORD OF DECISION
Site Name and Location
M-Area Hazardous Waste Management Facility (HWMF) Operable Unit
Savannah River Site
Aiken County, South Carolina
Appendix C of the draft Federal Facility Agreement (FFA) refers to this operable unit as the
M-Area Settling Basin, M-Area/Lost Lake (Building Numbers 904-510,904-1120).
Statement 01 Basis and Purpose
This document presents the selected interim remedial action for the M-Area HWMF
Operable Unit at the Savannah River Site (SRS), which was developed in accordance with
the Comprehensive Environmental Response, Compensation and Liability Act of 1980
(CERCLA), as amended by the Superfund Amendments and Reauthorization Act of 1986
(SARA), and to the extent practicable, the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP). This decision is based on the administrative record file
for this specific operable unit
Description of the Selected Remedy
The selected interim action remedy involves the stabilization and placement of all
contaminated materials under a low permeability cap. This remedy prevents physical
exposure to contaminants and mitigates further migration of contaminants to the
groundwater by minimizing a liquid medium pathway (rainwater percolation) for transport
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INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
A risk evaluation is currently being developed for the M-Area HWMF Operable Unit. A
final remedy will be selected following the evaluation.of any post-closure risks and will be
contained in the final Record of Decision (ROD).
The major components of the remedial action include:
.
Dewatering the basin.
.
Treating basin liquid and discharging the liquid to a permitted outfall.
.
Waste consolidation by stabilizing and compacting dewatered basin sludge.
.
Excavation of a portion of the process sewer line and associated soils and
contaminated soils from the seepage area and areas of Lost Lake.
.
Consolidation and compaction of excavated contaminated materials on top of the
stabilized sludge within the basin.
.
Installing a low permeability cap system over the basin.
Declaration Statement
The interim action is hereby selected by mutual agreement of the U.S. Department of
Energy and the U.S. Environmental Protection Agency. This interim action is protective of
human health and the environment, complies with Federal and State applicable or relevant
and appropriate requirements (ARARs) for this limited-scope action, and is cost-effective.
This action is interim and is not intended to utilize permanent solutions and alternative
treatment (or resource recovery) technologies to the maximum extent practicable for the M-
Area HWMF Operable Unit Because this action does not constitute the fmal remedy for
the M-Area HWMF Operable Unit, the statutory preference for remedies that employ
treatment that reduces toxicity, mobility, or volume as a principal element, although
partially addressed in this remedy, will be fully addressed by the final response action.
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INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
Subsequent actions are planned to address fully the threats posed by the conditions at the
M-Area HWMF. Because this remedy may result in hazardous substances remaining
within the operable unit above health-based levels, a five-year review will be conducted to
ensure that the remedy continues to provide adequate protection of human health and the
environment after commencement of the remedial action. Because this is an interim action
ROD, review of this operable unit and of this remedy will be conducted by the
Environmental Protection Agency (EPA) until a fmal remedial alternative for the M-Area
HWMF Operable Unit is selected.
f.. /-z.;/'71-
Date
~4-~
L. C. Sj m
Assistant Manager for Environmental
Restoration and Waste Management
U.S. Department of Energy
JUN 2 9 1992
Date
~tYJT~
JA Greer C. Tidwell
I Regional Administrator,
U.S. Environmental Protection Agency
Region N
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SUMMARY OF INTERIM ACTION
R-EMEDIAL ALTERNATIVE SELECTION
M-Area Hazardous Waste Management Facility Operable Unit
Savannah River Site
Aiken County, South Carolina
Prepared by:
U.S. Department of Energy
Savannah River Field Office
Aiken, South Carolina
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INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
Section
I.
II.
IT!.
IV.
v.
VI.
VIT.
VITI.
IX.
X.
XI.
Annendices
A.
B.
DECISION SUMMARY
T ABLE OF CONTENTS
Łau
Site and Operable Unit Names, Locations, and Descriptions
Operable Unit 'History and Compliance History
1
4
Highlights of Community Participation
. Scope and Role of Operable Unit within the Site Strategy
6
6
Summary of Operable Unit Otaracteristics
Summary of Operable Unit Risks
6
7
Description of Alternatives
Summary of Comparative Analysis of Alternatives
9
20
Selected Remedy
Path Forward
25
25
Statutory Determination
26
References for Development of ROD Format
Responsiveness Summary
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INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
I.
Site and Operable Unit Names, Locations, and Descriptions
The Savannah River Site (SRS) occupies approximately 300 square miles adjacent to the
Savannah River. principally in Aiken and Barnwell Counties of South Carolina (Figure 1).
SRS is a secured facility with no pennanent residents. The site is approximately 25 miles
southeast of Augusta, Georgia, and 20 miles south of Aiken. South Carolina. The average. .
population density in the counties surrounding SRS ranges from 23-560 people per square
mile with the largest concentration in the Augusta, Georgia, metropolitan area. Based on
1980 census data (1990 data not available), the population within a 50-mile (80 Ian) radius
of SRS is approximately 555,100.
SRS is owned by the United States Department of Energy (DOE). Westinghouse
Savannah River Company (WSRC) is a co-operator, providing management and operation
services for OOE. SRS produces tritium. plutonium. and other special nuclear materials
for national defense. The site also provides nuclear materials for the space program. and
conducts medical. industrial, and research efforts. The AIM Ale&, located in the northwest
portion of the SRS (Figure I), contains nuclear fuel fabrication buildings, office buildings,
and research areas~
The M-Area Hazardous Waste Management Facility (HWMF) is a source-specific operable
unit within the AIM Area Fundamental Study Area. The M-AIQ HWMF includes an
unlined surface impoundment (settling basin), a portion of an inactive process sewer line,
drainage and seepage areas, and a Carolina bay known as Lost Lake (Figure 2). The
nearest plant boundary is approximately 5800 feet northwest of the M-Area HWMF.
1
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INTERIM ACTION ROD
M.AREA HWMF
WSRC.RP.92.143
JUNE 25, 1992
@ - EII8:'-'
SAVANNAH RIVER
SITE
. .MIIing
"',
~
.
!
GEORGIA
. 0I4IC0II
~.:
~. . -i, .*
- -. ",'
--- .~
fU/' .+
" !'.""
. .
wi I I I I I
Vi 0 50 100 110 200
KiIom8I8a
I I
o ,
I I
2 J
....
I
4
I
5
Figure 1 Location of the Savannah River Site (SRS)
(Source: Modified from the Savannah River Environmental Report, 1990) .
2
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INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
t
N
I
~_.._:
I I
o lOCI
-
/
? ./
./
""-- ;/
Legend
~ 8M11anea-n 1118I8I(MILJ
"""'- ....
--- "'-s-
*"-* F.-
.
Figure 2 M-AJea HWMF
(Source: Modified from the 8RS Vadose Zone Characterization, 1990)
3
"
f
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INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
II.
Operable Unit History and Compliance History
Operable Unit History
The M-Area settling basin was constructed in 1958 to settle out metals (primarily uranium,
nickel, lead and aluminum) discharged from M-Area manufactUring operations. The
manufacturing processes consisted of aluminum fonning and metal finishing processes
which produced fuel and targets for SRS reactors. Waste effluents from the aluminum
forming and metal finishing processes were discharged from three production buildings
and two suppon laboratories to the settling basin through a process sewer line. The waste
effluents generally contained hydroxides, precipitates of aluminum. uranium, nickel, lead
and other metals, solvents (1,1, I-trichloroethane, trichloroethylene, and
tetrachloroethylene), acids, and caustics. Very low concentrations (<50 ppm) of
polychlorinated biphenols (PCBs) were detected in the early 19805 in soils in an isolated
portion of the drainage ditch downstream of the basin. No PCBs are known to have ever
been detected in the basin. The drainage ditch soils were excavated and stabilized with
cement in the basin during cl~ activities.
The basin dimensions were approximately 330 feet by 280 feet (surface dimensions) by 17
feet (depth) with a volumeaic capacity of approximately eight million gallons. Overflow
from the settling basin was directed to a natUral seepage area and ultimately to Lost Lake.
In July 1985, a pennitted wastewater treatment facility was placed in operation and
discharges to the settling basin were discontinued.
4
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INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
Compliance History
Remedial actions were started at the M - Area HWMF under the Resource Conservation and
Recovery Act (RCRA). In 1985, a RCRA Closure Plan was submitted to the South
Carolina Department of Health and Environmental Control (SCDHEC). The closure plan
underwent several reVisions prior to approval by SCDHEC in 1987. A Pan B Permit
Application for M-Area operations and for post-closure of the M-Area HWMF was also
submitted to SCDHEC. In September 1987, DOE received a Hazardous Waste Permit
(SCI-890-008-984) for container storage areas and post-closure care of the M-Area
HWMF. Cosure of the operable unit was initiated in 1988 and completed in 1990. In
1991, the closure certification was accepted by SCDHEC as being in compliance with
RCRA requirements.
Closure activities specifically included removal and treatment of any standing water
remaining in the basin; discharge of the effluent to the NPDES-permitted M-004 Outfall;
excavation, dewatering, and stabilization of the basin sludge with Portland cement;
placement, consolidation and compaction of stabilized sludge in the basin; excavation of a
portion of the process sewer line and contaminated soils associated with the sewer line,
drainage ditch, seepage area and Lost Lake; placement and compaction of contaminated
materials in the basin; construction of a low permeability cap over the settling basin; and
restoration of the area.
"
Remedial activities at the M-Area HWMF became subject to CERCLA when the entire SRS
facility was placed on the National Priorities List (NPL) in December 1989. Due to the
multiple source areas in close proximity and the co-mingling of contaminants emanating
from these source areas, the AIM Area has been designated a Fundamental Study Area.
5
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INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
The pmpose of this designation is to facilitate the coordination of remedy selection
decisions for the operable units in this area. The M-Area HWMF has been designated as a
source-specific operable unit within the NM Area Fundamental Study Area.
III.
Highlights 01 Community Participation
No comments were received during the public review period.
IV.
Scope and Role 01 Operable Unit within the Site Strategy
The selected remedy involves the placement of all contaminated materials under a low
permeability cap. The remedy prevents physical exposure to contaminants and mitigates
funher migration of contaminants from the settling basin to groundwater by minimizing a
liquid medium pathway (rainwater percolation) for transpon.
The interim action is consistent with any planned future actions for this operable unit.
Groundwater remediation is addressed in the ROD for the AIM AIea Groundwater Operable
Unit.
v.
Summary 01 Operable Unit Characteristics
Waste effluents from aluminum fonning and metal finishing processes were discharged
from three production buildings and two suppon laboratories to the M-Area settling basin
through a process sewer line. The waste effluents generally contained hydroxides,
precipitates of aluminum, uranium, nickel, lead and other metals, solvents (1,1,1-
trichloroethane, trichloroethylene, and tetrachloroethylene), acids, and caustics. Cracks in
the sewer pipeline allowed some effluent to leak into the ground, contaminating underlying
6
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INTERIM ACTION ROD
M.AREA HWMF
WSRC.RP.92.743
JUNE 25, 1992
soils. The pipeline was slip-lined after cracks and misalignments were discovered in 1983,
and an inactive portion was excavated in 1989 as pan of -the settling basin closure.
Contamination was detected in groundwater, surface water, soil, sediments, and air prior to
closure of the M-Area HWMF. Constituents evaluated in a 1985 risk analysis include
.aluminum, barium, cadmium, chromium, copper, cyanide, lead, lithium, mercury, nickel,
nitrate, phosphate, silver, sodium, zinc, depleted w:anium, PCBs, tetrachloroethylene, 1,1-
dichloroethylene, trichloroethane, and bis(2-ethylhexyl)phthalate. Chemical analyses
indicate that elevated levels (hundreds of pans per million) of contaminants appear to be
restricted to the area beneath the M-Area HWMF and the AIM Area. Very low
concentrations of PCBs « 50 ppm) were detected in the early 19805 in soils in an isolated
portion of the drainage ditch downstream of the basin. No PCBs are known to have ever
been detected in the basin.
The volume of waste within the settling basin was estimated to be 37,800 cubic yards. The
volume of contaminated soils and dried sludge in the overflow ditch, seepage area, process
sewer line, and Lost Lake was estimated to be 39,700 cubic yards.
VI.
Summary of Operable Unit Risks
A risk evaluation is currently being developed for the M-Area HWMF Operable Unit The
risk evaluation will be based on available data. A previous risk analysis performed in 1985
for the M-Area HWMF was used in the development of closure alternatives. 1be ~ults of
the previous risk analysis and available closure and post-closure data will also be uri1i7ed.
as appropriate, for evaluation of potential post-closure risk.
As noted in Section V, constituents evaluated in the 1985 risk analysis included aluminum,
barium, cadmium, chromium, copper, cyanide, lead, lithium, mercury, nickel, nittate,
7
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INTERIM ACTION ROD
M.AREA HWMF
WSRC.RP.92.743
JUNE 25, 1992
phosphate. silver. sodium. zinc. depleted uranium. PCBs. tetrachloroethylene. 1.1-
dichloroethylene. trichloroethane, and bis(2-ethylhexyl)phthalate. Chemical analyses
indicate that elevated levels (hundreds of parts per million) of contaminants appear to be
restricted to the vadose and groundwater zones beneath the M-Area HWMF and the NM
Area.
Risk assessment work conducted in 1985 to evaluate closure options for the M-Area
HWMF indicated that contamination was present in groundwater. surface water. soil.
sediments, and air. The M-Area risk evaluation program cunendy under development also
is considering these media. However. the $(urrent risk work addresses potential risks
through these media based on post-closure conditions. Furthermore, the risk evaluation
work is being conducted in tWo parts based on media-specific units. within the AIM Area
Fundamental Study Area.
Contaminated sediments and surface soils of the M-Area HWMF were excavated and
placed in the basin during closure. The basin then was covered with a low permeability
soil cap. Therefore. cwrent exposure through surface soil and sediment pathways is
minimized because of this soil remediation. This aspect of sediment and surface soil
exposure pathways will be addressed in detail in the risk evaluation for surface pathways.
The potential pathways for human exposure are through surface, subsurface, and
atmospheric transport of contaminants. However. as noted above, the extent to which soil
and cMiment remediation have eliminated surface and associated atmospheric pathways is
being evaluated in the M-Area risk evaluation. Subsurface contamination associated with
the M-Area HWMF groundwater is cunently being addressed as pan of the on-going AIM
Area Groundwater Corrective Action Program. Therefore. M-Area HWMF subsurface unit
8
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INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
risks will be addressed as part of the separate risk assessment for the NM Area
Groundwater Operable Unit
Potential human health risks associated with surface pathways will be evaluated funher in
the risk evaluation under development. Because these media were remediated during
closure, the risk evaluation should show reduced or no potential for risks from these
media.
Results of the ecological assessment conducted in 1985 indicate that adverse effects on
river quality and wildlife for any of the three closure alternatives examined would be
insignificant. The risk evaluation currently under development will characterize any
ecological affects for post-closure conditions. Lost Lake is cUITently being monitored for
any ecological impacts from closure activities. Results of this monitoring program will be
included in future reviews of the operable uniL
VII. Description or Alteraatives
~"'..
Remedial alternatives were developed for the M-Area HWMF based on effective
d' .r;:-~
technologies available ~t the time the RCRA Closure Plan was ~arcd~ The RCRA
~ '--
Closure Plan was initially submitted to SCDHEC in 1984.and waS.lppiOV~ following
several revisions, in 1988. Options regarding the M-Area HWMF evaluated at that time
included:
Alternative 1
No Action
Alternative 2
No Waste Removal, Waste consolidation, Treattnent, and Oosure
9
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INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
Alternative 3
Waste Removal and Qosure
Alternative 2 was selected within the RCRA closure process in 1988 as the most technically
effective of the three alternatives for protection of human health and the environment.
Closure of the M-Ares HWMF was begun in 1988 and completed in 1990 utilizing a
modification of the components of Alternative 2. The closure was certified in 1991 by
SCDHEC as being in compliance with RCRA and state requirements. The closure is
currently considered an interim action under CERa..A. However, upon completion of the
risk evaluation, SRS will submit appropriate documentation to EPA, SCDHEC, and the
public requesting that the alternative be designated a fmal action. This section contains a
description of each of the three alternatives as they were developed and considered under
NCP guidelines.
Alternative 1: No Action
Under the No Action Alternative, the settling basin would be allowed to dry by natural
evaporation. The soils in the drainage ditch, seepage area, and Lost Lake would remain in
place. The groundwater monitoring program would continue for a 3O-year period or as
required to remediate the AIM Area groundwater.
Treatment Cotnponents. No treatment would be instituted for the No Action Alternative.
Materials within the settling basin and contaminated soils associated with the drainage
ditch, the sewer line. and Lost Lake would remain in place.
Enpneerin, Controls. With the exception of continued groundwater monitoring. no
engineering conttols would be required under the No Action Alternative. As stated in the
approved Application for Post-Closure Permit. the existing groundwater monitoring
10
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INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP.92.743
JUNE 25, 1992
network would be utilized to monitor groundwater in the vicinity of the M-Area HWMF.
Post-closure monitoring will be continued for 30 years following the date of completing
closure plus any additional time required to separately remediate the AIM Area
groundwater.
Institutional Controls: Public access to areas within SRS is controlled by existing security
personnel. Access specifically to the M-Area HWMF would be resnicted through an
exclusion fence, which surrounds the immediate area of the settling basin. Exclusion fence
maintenance would occur on a periodic basis. Additionally, a deed resniction of the M-
Area HWMF would be maintained with the Aiken County zoning authority as specified in
South Carolina Hazardous Waste Management Regulation (SCHWMR) R.61-79.264.119.
A survey plat indicating the location and dimensions of the basin and the type and quantity
of waste within the basin would be filed with the Aiken County zoning authority as
specified in SCHWMR R.61-79.264.120.
Ouanti\Y of Waste. Waste within the settling basin and contaminated soils associated with
the drainage ditch. the sewer line. and Lost Lake would remain in place under the No
Action Alternative. The volume of waste that would remain within the settling basin is
estimated to be 37.800 cubic yards.
Implementation Requirements.
The No Action Alternative requires no special
implemenwion procedures and can be initiated immediately.
Estimated Construction and Operation and Maintenance (O&M) Costs. Additional
monitoring wells would not be installed under the No Action Alternative. Costs for this
alternative were originally estimated to be:
.
Capital Cost
$0
11
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INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
.
Annual O&M Costs
$20,000
ARARs Associated with the Considered Alternative. The No Action Alternative would
allow the continued migration of chemical residuals associated with the basin to
groundwater within the AIM Area. Risks to human health would still exist due to
associated smface migration pathways.
Alternative 2:
Closure
No Waste Removal.
Waste
Consolidation. Treatment. and
This alternative involves pumping and treating any standing water remaining in the basin;
excavating, dewatering, and stabilizing the basin sludge with Ponland cement; placement,
consolidation and compaction of stabilized sludge intO the basin; discharging the effluent to
the NPDES permitted M.()()4 Outfall; consolidation by excavating and placing contaminated
soils associated with the seepage area, a portion of the sewer line, and Lost Lake intO the
basin; and installing a low permeability cap over the settling basin.
Treatment Components. The free liquid in the settling basin and Lost Lake. would be
pumped to a pennittcd temporary wastewater treatment facility (WTF) for processing. The
treatment steps of the WTF would consist of pH adjustment, polymer addition. clarification
by precipitation, and filtration. Following treatment, the effluent would be discharged at
the NPDES-permittcd M-004 Outfall. Pumping rates would not exceed historical overflow
rates (200 to 300 gallons per minute) so as not to disturb the underlying sludge layer.
Sludge dewatering would take place by dredging and pumping sludge materials through a:
filter press. The filter cake resulting from this operation alone would have a solids content
on the order of 6S~ (i.e.. the consistency of clay). The filter cake (sludge) would then be
further stabilized by the addition of kiln dust and Type I PonJand Cement, and the mixture
12
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INTERIM ACTION ROD
M-AREA HWMF
WSR C-RP-92- 743
JUNE 25, 1992
would be placed back into the basin. Air entrainment would be minimized by design of the
pumping apparatus.
En~neerine Controls. Following placement of the stabilized sludge, contaminated soils
and material from sUlTOunding areas including Lost Lake will be excavated and placed
within the basin, on top of the stabilized sludge. Areas from which contaminated media
would be removed are shown in Figure 3. A low permeability cap would then be placed
over the settling basin as an engineering control. The cap would be designed and
constnlcted to provide a permeability of no more than 1.0 x 10-7 crn/s. The RCRA cap
installed over the M-Area settling basin would.consist of an impermeable layer overlain by
a drainage layer which would, in turn, be protected by a layer of soil. The impermeable
layer would include 24 inches of compacted clay and a synthetic Hypalon@ membrane.
The drainage layer would consist of open-graded stone and incorporate a perimeter drain.
It would be overlain by a synthetic geotextile f1lter fabric to prevent soil particles from
migrating into the drainage layer and clogging the interstices of the stone. The surface soil
layer would be sloped to promote drainage and vegetated 10 minimize potential for erosion.
A schematic of the soU cap is presented in Figure 4.
In accordance with the approved post-closure permit application, the existing groundwater
monitoring network would be utilized to monitor groundwater in the vicinity of the M-Area
HWMF. Groundwater monitoring will continue for 30 years following completion of
closure (1990) of the settling basin plus any additional time required to complete on-going
remediation of AIM ~ groundwater.
Institutional Controls.
Institutional controls would be identical to those described in
Alternative 1.
13
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Lo « Lake
(C.O.E)
Elevated Area
(No Sediments Removed)
Drainage
Ditch
Lost Lake
M Area
Settling Basin
Seepage
Area (A. B)
Excavation Depth 6'
Excavation Depth 2'
Excavation Depth 1'
Excavation Depth 6'
Excavation Depth 2"
Fence
Basin Capacity .
7.200 yd3
10.000 yd3
16.000 yd3
9.100 yd3
2.200 yd3
44.500 yd3
50,000 yd3
»5
3
If
»
O
D
a*
10 VI
Figure 3
*
Areas of Contaminated Soil Removal from the M-Area HWMF
-------
Basin
Cap
VI
,
\
Slope 3.5% Mn.
Hypalon Uner
Geotextlle Fabrtc
~
........................................... ... ................ ................
[[[ ::. N . .:.:.: -.:.:.:.:.:.:.:.:.:.:.:.:-. :.:.:.:.:.:.::. .:.:.:.:.:. :.:
....................................... .....- ... .............. ....... .......
................ ....... ... .............. ...... .......
.. ......... ... .............. ...... .......
,
Basin RI
""
2'.0.
..-..
12.
0' I
o 2
Approximate Scale (Feet)
=::-
.Z
>-i
~tI:I
l!2~
>-
=::
=>
~(j
=::-i
"IjO
z
~
o
o
...
6" Drainage Pipe
Slope 0.58/. Min.
to Drainage Ditch
~
.rJ)
C~
Z(j
tI:I'
==
N""C:I
CA'
.. \D
N
1006 ,
'C~
-------
INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
Ouanti~ of Waste. The contaminated soils and dried sludge from the overflow ditch,
seepage area, and Lost Lake would be excavated, and a ponion of the process sewer line,
manholes, and approximately 2 feet of soil beneath the sewer line between the settling basin
and manhole No.1 would be removed (Figure 3, Section ll). The total volume of soil to
be excavated is shown below:
Overflow ditch
6,700 yd3 .
9,800 yd3
Remainder-of seepage area
Lost Lake
22,100 yd3
Process sewer, manholes, and soil
1.100 yd3
1UfAL
39,700 yd3
All excavated materials would be placed in the settling basin and compacted to suppon the
basin cap. Common fill would be added to level the material to the top of the basin. The
estimated amount of materials cunently within the settling basin was 37,800 cubic yards.
Intplementation ReQ)1irements. Construction of a cap is a commonly implemented
operation that has been accomplished at numerous sites. Clearing and grubbing would be
required for access of heavy machinery. Liner installation would be scheduled during
suitable climatic conditions. The estimated construction schedule for complete closure of
the M-Area HWMF was originally estimated to be 18 to 24 months.
Cap maintenance can be readily implemented. Periodic cap maintenance would involve
cutting grass and clearing any accumulation in the drainage swales. Inspections would be
required to determine whether repairs to the cap, drainage system, or exclusion fence are
required.
16
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INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
Estimated Consttuction and Operation and Maintenance Costs. The estimated cost for
Altemarive 2 was originally estimated to be:
.
Capital Cost
$3,000,000 - $5,000,000
.
Annual O&M Costs
$20,000
ARARs Associated with the Considered Alternative. Alternative 2 requires remedial
activity that may impact surface water and potential wetland areas. To ensure consistency
with the Oean Water Act, erosion control must be employed through Best Management
Practices to mitigate or minimize impacts to surface water from remedial activities. Also,
remedial activities must be controlled to minimize the effects to wetland functions and
beneficial values.
Federal RCRA regulations regarding capping would be relevant and appropriate for
implementation of Alternative 2. The single synthetic liner would meet the equivalent
perfonnance standard of SCHWMR R.61-79.265.310. These requirements include the
following:
.. .
provide long-term minimization of migration of contaminants
.
function with minimum maintenance
.
promote drainage and minimize erosion or abrasion of the cover
.
accommodate settling and subsidence to maintain cover integrity
.
have a permeability less than that of natural subsmface soils.
Materials being handled in this remedy may contain both hazardous and radioactive
components and may have to be handled as mixed waste (53 FR 37045, September 23,
1988).
17
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INTERIM ACTION ROD
M.AREA HWMF
WSRC.RP.92.743
JUNE 25, 1992
Alternative 3: Waste Removal and Closure
Under this alternative, the liquid in the settling basin would be processed through the
pennitted wastewater treatment facility and discharged to NPDES outfall M-004.
Contaminated soils would be excavated from the settling basin and seepage area. a portion
of the sewer line, and Lost Lake. Soils and sludges would be placed in a treatment, storage
and disposal (TSD) facility within SRS. The settling basin would be backfilled with clean
fill.
Treabnent Components. The remaining liquid in the basin would be processed through the
permitted WTF and discharged.to NPDES outfall M-004. The gelatinous sludge layer in
the basin would be stabilized to facilitate removal and handling. The sludge would be
treated with absorbants or drying agents to produce a material that could be removed by
nannal excavation methods.
Contaminated soils and sludges would be removed from the basin. overflow ditch, seepage
area, and Lost Lake. Also the process sewer line, manholes, and 2 feet of soil beneath the
sewer line betWeen the basin and manhole No.1 would be removed (Figure 3, Section ll).
The soils removed from the basin and vicinity would be placed in a TSD facility within
SRS.
EniPneerinl Controls. The basin and vicinity would be backfilled with clean fill material
under AltemaDve 3. The area of the basin would then be covered with topsoil and graded
and seeded for erosion control.
Institutional Controls. No exclusion fence, deed resttiction or other institutional controls
would be required under this alternative.
18
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INTERIM ACTION ROD
M-AREA HWMF
WS ~ :-RP-92-743
. J ~E 25, 1992
Ouantity of Waste. Original estimates of the total volume of material required to be
removed from the basin and vicinity were as follows:
Sludge/soil beneath basin
14,400 yd3
5,900 yd3
Stabilized sludge
Overl1ow ditch and adjacent
seepage area
6,700 yd3
Remainder of seepage area
9,800 yd3
22,100 yd3
Lost Lake
Process sewer, manholes, and soil
1.100 yd3
60,000 yd3
1UI'AL
Irnplementation Requirements. Implementation of this alternative requires standard
excavation equipment and procedures. However, approximately 3,000 truck loads of
materials containing chemical and possibly radioactive constituents would be hauled from
the unit to a permitted TSD facility within SRS. Approximately 3,000 truck loads of clean
fill would be hauled back to the unit. Clearing and grubbing would be required for heavy
equipment access and staging areas. Maintenance of the basin and vicinity could easily be
implemented following closure. The time required for complete closure of the M-Area
HWMF under this alternative was origin all y estimated to be 18 to 24 months.
Estimated Construction and Operation and Maintenance Costs. The costs for
implementation of Altcmative 3 were originally estimated to be:
.
Capital Cost
$150,000,000
.
Annual O&M Costs
$20,000
19
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INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
The capital cost reflects values associated with removal and temporary storage at a TSD
facility and final disposal on SRS property.
ARARs Associated with the Considered Alternative. As described in Alternative 2, erosion
control measures and management practices to minimize impacts to wetlands would have to
be employed during remedial activities.
Removed materials contain both hazardous and radioactive components and would have to
be handled as mixed waste. Treaunent, storage and disposal of hazardous components are
regulated under SCHWMR R.61-79.264. The radioactive components are controlled
under DOE Order 5820.2A, RCRA regulations (40 CFR ~~ 193 and 764), and Atomic
Energy Act (AEA) regulations (10 CFR ~ 61). Shipment of hazardous and radioactive
substances is regulated under Department of Transponation regulations (49 CFR II 100 to
177), and OOE internally controls the shipment of radioactive wastes under DOE Order
1540.1.
VIII. Summary of Comparative Analysis of Alternatives
The NCP (40 CFRA300.430 (e) (g» sets forth nine evaluation aiteria that provide the basis
for evaluating alternatives and subsequent selection of a remedy. The aiteria are:
.
Ovcnll protection of human health and the environment
.
Compliance with ARARs
.
Long-tam effectiveness and pennanence
.
Reduction of toxicity, mobility, or volume through treatment
.
Short-term effectiveness
20
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INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
. Implementability
. Cost
. State acceptance
. Community acceptance
Overall Protection of Human Health and the EnvironmenL Alternative I, the No Action
Alternative, would allow continued leaching of chemical residuals associated with the basin
and surrounding media to the groundwater.
Alternative 2. No Waste Removal. Waste consolidation. Treatment, and Closure. achieves
overall protection by minimizing potential exposure to contaminated media and minimizes
the transport of chemical residuals to groundwater. This is accomplished through
stabilization of the sludge in a cement matrix, waste consolidation by excavation and
placement of surrounding contaminated soils in the basin, and installation of a low
permeability cap over the basin.
Alternative 3. Waste Removal and Closure, achieves overall protection of human health by
removing contaminated media associated with the seepage basin. However, under this
alternative the contaminated media is transported to a TSD facility at another location within
SRS. Potential risks associated with exposure to the chemical residuals aIe, in effect,
relocated.
Conwliance with J\pJ)licable or Relevant and Appropriate Requirements (ARARst No
chemical-specific action levels exist for chemical residuals in soils. The No Action
Alternative would. however. allow continued leaching of chemical residuals to the
21
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INTERIM ACTION ROD
M.AREA HWMF
WSRC.RP.92.743
JUNE 25, 1992
groundwater within the. AIM Area and potentially cause exceedance of promulgated
groundwater standards.
Alternative 2 would control incidental exposure to chemical residuals at the M-Area
HWMF. A particular action-specific ARAR for Alternative 2 is the regulations regarding
capping, S~R R.61-?9.265. The cap for this alternative must be designed and
installed according to RCRA requirements to comply with the action-specific ARAR.
Capping would help achieve groundwater chemical-specific requirements because it would
minimize leaching of chemical residuals to groundwater.
Under Alternative 3, the removed materials must be stored at a storage facility designed to
meet the TSD facility requirements set fonh under regulations SCHWMR R.61-79.264.
Lone-term Effectiveness and Pennanence. Alternative 1 would allow continued leaching of
chemical residuals to the groundwater, thus failing to provide a long-tenD remedy of the M-
Area HWMF. Alternative 2 would effectively and permanently minimize the migration of
chemical residuals to groundwater through stabilization of sludge materials and installation
of the low permeability cap. Use of Alternative 3 would permanently remove sludges and
other associated contaminated media from the basin, but the excavated materials would then
have to be relocated to a TSD facility within SRS until a pennanent treatment or disposal
remedy is developed. Cap maintenance for Alternative 2 would continue for at least 30
years (the post-closure care period), with extension of this period reviewed every five
years. Maintenance of the exclusion fence would also continue for at least 30 years.
Reduction ofToxici~. Mobili\'y. or Volume Throueh Treatment Alternative 1 provides no
treatment to reduce the toxicity, mobility, or volume of chemical residuals. Capping under
Alternative 2 would significantly reduce the mobility of chemical residuals within the basin
22
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INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
although the volume of contaminants will remain unchanged. This alternative would
reduce the toxicity and mobility of chemical residuals through soil stabilization with
Ponland cement This treatment would chemically bind soils and chemical residuals into a
stable solid block. Alternative 2 would also consolidate waste materials in one location,
thereby reducing the surface area of leachable constituents. Alternative 3 reduces the
volume of contaminants specifically at the M-Area basin and surrounding media; however,
the excavated quantity of waste is relocated to a TSD facility within SRS and will ultimately
require treatment and eventual disposal at a future date when a permanent remedy is
developed.
Short-term Effectiveness. Implementation of Alternatives 1 or 2 would pose little or no risk
to the community or remedial workers through exposure to chemical residuals. Little or no
significant environmental impacts would occur from implementation of either of the
alternatives. Impacts to Lost Lake would be mitigated through restoration activities.
Alternative 3 requires 3,000 truck loads of potentially contaminated material to be
transported to anothel' location within SRS. Remedial workers would have the potential for
exposure to waste materials due to the transportation. Also, potential accidents resulting
from transponation of the materials may expose other SRS employees or contraCtorS.
Consttuction schedules for the alternatives were originally estimated as follows:
Alternative 1
No Action
None
Alternative 2
No Waste Removal, Waste Consolidation, Treatment, and Oosure
18 - 24 Months
Alternative 3
23
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INTERIM ACTION ROD
M.AREA HWMF
WSRC.RP.92.743
JUNE 25, 1992
Waste Removal and Closure
18 - 24 Months
The cap under Alternative 2 would be kept in place indefinitely to minimize infiltration of
precipitation. Alternative 3 requires no engineering controls.
Implementabili(y. The proposed alternatives would pose no significant consttuction or
operational difficulties. Materials and consttuction services are readily available for
Alternatives 2 and 3. Both Alternatives 2 and 3 would require approval from SCDHEC for
certain elements of the remedies (i.e., cap design and TSD facility storage). Periodic
inspections and, as necessary, repair of the cap would be required under Alternative 2.
~ The originally estimated present worth costs for each alternative are presented below:
Alternative 1
No Action
$600,000
Alternative 2
No Waste Removal, Waste Consolidation,
Treatment, and Closure
Alternative 3
$3.000.000 - $5.000,000
Waste Removal and Oosme
$150.000,000
The original estimated costs for all three alternatives include an annual O&M cost of
$20.000 for a 3O-year period for groundwater monitOring. These costs do not include
monitoring beyond the 30-year period potentially required to complete AIM Area
groundwater mnediation.
State Acceptance. SCDHEC has reviewed the closure and post-closure plans and concurs
with the preferred alternative for the M-Area HWMF. The M-Area HWMF was Closed
24
-------
,-
INTERIM ACTION ROD
M.AREA HWMF
WSRC.RP.92.743
JUNE 25, 1992
using Alternative 2' in 1990. SCDHEC accepted certification of the M-Area HWMF closure
in 1991.
Community Acc~ptance. (To be addressed by DOE/EPA after the Proposed Plan public
comment period.)
IX.
Selected Remedy
The preferred interim action alternative for the M-Area HWMF is Alternative 2: No Waste
Removal, Waste Consolidation, Treatment, and Closure. The selected remedy (Alternative
2) involved pumping and treating the standing water remaining in the basin; excavating,
dewatering, and stabilizing the sludge in the basin with Portland cement; placement,
consolidation and compaction of stabilized sludge into the basin; discharging the effluent to
the NPDES-permittcd M-004 outfall; waste consolidation by excavating and placing within
the basin contaminated soils from the seepage area, a portion of the sewer line, and Lost
Lake; and installing a low permeability cap over the settling basin. This alternative
implements an interim remedial action to protect human health and the environment The
goal of this remediation was to minimize migration of contaminants to the groundwater and
eliminate surface ttansport pathways. Upon completion of the unit risk evaluation, this
interim action will become a final action for review and approval.
X.
Patb Forward
Remedial actions regarding the M-Area HWMF are currently being addressed as interim
actions. "Path Forward" activities associated with this operable unit include a risk
evaluation of the unit and continued monitoring and management of Lost Lake. Upon
completion of this risk evaluation, a final remedy will be selected.
25
-------
INTERIM ACTION ROD
M-AREA HWMF
WSRC-RP-92-743
JUNE 25, 1992
XI.
Statutory Determination
The preferred alternative for the M-Area HWMF is Alternative 2: No Waste Removal.
Waste Consolidation. Treatment, and Closure. The alternative was selected for its ability
to provide overall protection of human health and the environment through reduction of
associated risks and compliance with ARARs. The remedy is protective because it prevents
physical exposure to contaminants by use of containment and institutional controls and
mitigates fUnher migration of contaminants to the groundwater by minimizing a liquid
medium pathway (rainwater percolation) for transpon.
Alternative 2 appears to provide the best balance with respect to the nine evaluation criteria
specified in the NCP. Alternative 2 is more technically effective than Alternative 3 in
providing a remedy for the M-Area HWMF and is also more cOSt-effective. Stabilization
and capping under the preferred alternative significantly minimizes the potential for
chemical residuals to leach into groundwater. Alternative 2 is preferred over Alternative 3
which reduces the volume of contaminated media associated with the settling basin.
relocates the material to a TSD facility within SRS. and would require transponation of
approximately 60.000 cubic yards of waste material containing both hazardous and
radioactive constitUents. This action is interim and the final ROD for this operable unit will
address the pennanence of the final action and the preference for any treatment utilized in
the final action to n=duce the mobility toxicity and volume of hazardous substances.
26
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Appendix A
References for Development of ROD Format
Crane. Jeffrey L.. 1992. "Working Meeting Notice for M-Area RODs. M-Area
Groundwater. M-Area Settling Basin. Met Lab Basin." Letter to Chris Bergren
(WSRC). U.S. Environmental Protection Agency. Region IV. Atlanta, GA. March
12. 1992. .
EPA.1989. "A Guide to Developing Superfund Records of Decision," OSWER Directive
9335.3-02FS-l, U.S. Environmental Protection Agency, Washington. D.C..
November 1989.
EPA,I991. "Guide to Developing Superfund No Action. Interim Action. and
. Contingency Remedy RODs." OSWER Publication 9355.3-02FS-3. U.S.
Environmental Protection Agency, Washington. D.C., April 1991.
Longest, Henry L, and Bruce M. Diamond. 1990. "Suggested ROD Language for
Various Groundwater Remediation Options," OSWER Directive 9283.1-03, U.S.
Environmental Protection Agency. Washington, D.C., October 10. 1990.
WSRC, 1990. "RCRA Facility Investigation/Remedial Investigation Program Plan,"
WSRC-RP-89-994, Chapter 15. Westinghouse Savannah River Company, Aiken,
South Carolin~ September 1990.
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Appendix B
. Responsiveness Summary
(No commentS were received during the public comment review period.)
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