PB97-963112
EPA/541/R-97/036
March 1998
EPA Superfund
Explanation of Significant Difference
for the Record of Decision:
Lawrence Livermore Laboratory
(USDOE) (Treatment Facilities A & B)
Livermore, CA
4/16/1997
-------
-------
UCRL-AR-1255S5
Explanation of Significant Differences for
Treatment Facilities A and B
Lawrence Livermore National Laboratory
Livermore Site
Technical Editors
L. L. Berg*
E.N. Folsom
M. D. Dresen*
R. W. Bainer
A. L. Lamarre
Contributors
L. L. Berg*
R. T. Depue
M. D. Dresen*
K. J. Heyward
S. N. Shukla
April 1997
* Weiss Associates, Emeryville, California
Environmental Protection Department
Environmental Restoration Program and Division
-------
-------
UCRL-AR-125555 Explanation of Significant Differences for April 1997
Treatment Facilities A and B, LLNL Liv. Site
Table of Contents
1. Introduction 1
2. Remedy Selected in the ROD 3
3. Description of the Significant Differences and the Basis for the Differences 3
3.1. Description 3
3.2. Basis 4
3.3. Summary 6
4. Support Agency Comments 6
4.1. EPA Comments and DOE/LLNL Responses 6
4.2. DTSC Comments and DOE/LLNL Responses 7
4.3. RWQCB Comments and DOE/LLNL Responses 8
5. Affirmation of the Statutory Determinations 9
References 10
List of Figures
Figure 1. Location of Treatment Facilities A and B at the Livermore Site 2
List of Tables
Table 1. Significant differences between the original and proposed remedies 5
Table 2. TFA equipment replacement schedule 6
4-97/ERD-l 25555 :rtd
-------
-------
UCRL-AR-125555 Explanation of Significant Differences for April 1997
Treatment Facilities A and B, LLNL Liv. Site
1. Introduction
On August 5, 1992, the Record of Decision (ROD) (Department of Energy [DOE], 1992) was
signed, documenting the final cleanup plan for the Lawrence Livermore National Laboratory
(LLNL) Livermore Site in Livermore, California. As required under Section 117(c) of the
Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA),
as amended by the Superfund Amendment and Reauthorization Act of 1986 (SARA), and pursuant
to 40 Code of Federal Regulations (CFR) Section 300.435 (c)(2)(i) (Fed. Reg. Vol. 55, No. 46
[March 8, 1990]), this Explanation of Significant Differences (ESD) describes a change from an
ultraviolet/hydrogen peroxide (UV/H.2&2) and air stripping ground water treatment system for
volatile organic compounds (VOCs) described in the ROD, to air stripping only at Treatment
Facilities A and B (TFA and TFB) (Fig. 1). An ESD is required when significant, but not
fundamental, changes are made to the final remedial action plan described in the ROD.
The lead regulatory agency for this ESD is the U.S. Environmental Protection Agency (EPA).
In addition to the EPA, the San Francisco Bay Regional Water Quality Control Board (RWQCB)
and the California Department of Toxic Substances Control (DTSC) oversee the LLNL Livermore
Site cleanup and have commented on this ESD. All comments and DOE/LLNL responses are
presented in Section 4.
This ESD includes a brief summary of the remedy selected in the ROD, a description of the
proposed change, and a description of why DOE/LLNL are making this change to the selected
remedy. This ESD was prepared according to EPA guidance (EPA, 1991; 1992).
The changes described in this ESD were presented to the Community Work Group on
August 14, 1996. Pursuant to 40 CFR Section 300.435(c)(2)(i), a public comment period is not
required for an ESD, and all regulatory agencies overseeing the Livermore Site agreed that a public
comment period was not necessary for this ESD. A notice will be published in local newspapers
(The Independent, Tri-Valley Herald, and Valley Times) that briefly summarizes this ESD.
This ESD will be placed in the LLNL repositories for interested members of the public to
review. One repository is located at the Livermore Public Library, 1000 South Livermore Avenue.
Library hours are Monday through Thursday, 10:00 a.m. to 9:00 p.m.; Friday, 10:00 a.m. to
6:00 p.m.; Saturday, 10:00 a.m. to 5:00 p.m.; and Sunday 1:00 to 5:00 p.m. The second
repository is at the LLNL Visitors Center on Greenville Road. Visitor Center hours are Monday
through Friday, 1:00 to 4:00 p.m. The Visitors Center also contains the Administrative Record,
which contains all documents that form the basis for the Livermore Site cleanup plan.
The site description and history are described in the Livermore Site Remedial Investigation
Report (Thorpe et al., 1990), the Feasibility Study (Isherwood et al., 1990), the ROD (DOE,
1992), and the Remedial Action Implementation Plan (Dresen et al., 1993).
4-97/ERD-125555:rtd
-------
UCRL-AR-125555
Explanation of Significant Differences for
Treatment Facilities A and B, LLNL Liv. Site
April 1997
Direction of treated water flow
Scale: Feet
^
500
To Arroyo Las Positas
ERD-LSR-96-0058
Figure 1. Location of Treatment Facilities A and B at the Livermore Site.
-------
UCRL-AR-J25555 Explanation of Significant Differences for April 1997
Treatment Facilities A and B, LLNL Liv. Site
2. Remedy Selected in the ROD
TFA and TFB are designed and operated to treat ground water containing VOCs and to
hydraulically control the western and southwestern offsite plumes. TFA began operating in
September 1989, and TFB began operating in October 1990. The primary VOCs in ground water
at TFA are tetrachloroethylene (PCE) and 1,1-dichloroethylene (1,1-DCE). Trichloroethylene
(TCE) and carbon tetrachloride are the primary VOCs at TFB. Design influent concentrations for
both facilities are discussed in Boegel et al. (1993).
TFA consists of a commercially available UV/H2O2 ground water treatment system and an air
stripper. The original facility was designed to treat 100 gallons per minute (gpm). Early
remediation concentrations were as high as 230 parts per billion (ppb) PCE and 14 ppb 1,1-DCE at
TFA. Recently the facility was modified and is now treating up to 300 gpm at concentrations of
about 34 ppb PCE and 5 ppb 1,1-DCE (September 1996) as new wells and pipelines are
connected to the facility. Treated ground water from TFA is discharged to a recharge basin south
of East Avenue (Fig. 1).
TFB also consists of a commercially available UV/H2O2 ground water treatment system and an
air stripper. Early remediation concentrations were as high as 140 ppb TCE and 4 ppb carbon
tetrachloride, and concentrations are currently about 42 ppb TCE and 1.5 ppb carbon tetrachloride
(September 1996). Treated effluent is discharged to a surface drainage ditch that flows north into
Arroyo Los Positas in the northwest corner of the Livermore Site.
Facility component specifications and Process and Instrument Diagrams for TFA and TFB are
presented in Boegel et al. (1993).
3. Description of the Significant Differences and
the Basis for the Differences
The significant differences between the remedy presented in the ROD and the proposed remedy
are described below.
3.1. Description
Because of increasing flow rates from the wellfield to enhance offsite plume capture, TFA has
recently become less efficient in remediating VOCs (Lamarre and Ko, 1996). Although effluent
concentrations occasionally exceed the 5 ppb total VOC discharge limit, they have never exceeded
Maximum Contaminant Levels for any individual VOC. In the summer of 1996, DOE/LLNL
began investigating a higher efficiency air stripper. When reviewing the specifications for a higher
efficiency air stripper, DOE/LLNL determined that they could remediate all VOCs below discharge
limits at TFA without operating the UV/H2O2 unit. It was also determined that a similar change at
TFB would eliminate the need for the TFB UV7H2O2 unit. This change also reduces the costs and
hazards involved in operating and maintaining the UV/H2O2 units.
4-97/ERD-l 25555 :rtd
-------
UCRL-AR-125555 Explanation of Significant Differences for April 1997
Treatment Facilities A and B, LLNL Liv. Site
During preparation of the ROD, the Community Work Group indicated a preference for ground
water remediation by UV/H2O2 because it destroys VOCs, whereas air stripping removes VOCs
and collects them on granular activated carbon (GAC). VOCs on GAC are then destroyed during
regeneration, or the GAC is disposed. Due to higher initial PCE and 1,1 -DCE concentrations and
the community preference, UV/H2O2 was incorporated into the original design to destroy many of
the VOCs prior to air stripping. With the initially high VOC concentrations, air stripping alone
would not have been as effective for the anticipated flow rates. Because VOC concentrations have
been reduced by an order of magnitude (Section 2), and flow rate has increased from 50 gpm to
greater than 300 gpm, the system is not designed for current conditions, and the cost and chemical
hazards of using UV/H2O2 no longer favor this technology.
The benefits for the proposed remedy include:
• Meeting cleanup objectives faster by increasing the capacity of the treatment facility;
• Increased safety by eliminating the handling of hazardous material (H2O2);
• Cost reduction through eliminating purchase of H2O2, reduced equipment maintenance,
and reduced electrical cost; and
• Using an accepted and proven technology.
Because of these benefits, DOE/LLNL and the regulatory agencies chose to eliminate the
UV/H2O2 units and replace them with higher efficiency air strippers. The Community Work
Group accepts the proposed remedy.
3.2. Basis
Table 1 describes the significant differences between the original and proposed remedy. Air
permitting, reporting and analysis costs will remain the same from the original remedy to the
proposed remedy.
GAC replacement frequency and costs will not increase due to the proposed remedy. Time
estimates for replacing the GAC (Boegel et al., 1993) were based on assumed initial
concentrations. However, over the last six years, the GAC effluent has always been below the
Bay Area Air Quality Management District's (BAAQMD's) discharge limits and never necessitated
GAC replacement. The GAC has been replaced about once a year as part of routine maintenance.
The GAC will change from one 200 pound unit to two 1,500 pound units (3,000 pounds total) to
accommodate the increased air flow rate. DOE/LLNL will continue to monitor the GAC effluent
with an organic vapor analyzer according to the schedule and requirements established by
BAAQMD. As soon as effluent concentrations begin to approach BAAQMD discharge limits, the
GAC will be replaced.
4-97/ERD-125555:rtd
-------
UCRL-AR-125555
Explanation of Significant Differences for
Treatment Facilities A and B, LLNL Liv. Site
April 1997
Table 1. Significant differences between the original and proposed remedies.
Item
Original remedy
Proposed remedy
Equipment
Flow rate
Electrical costs
H2O2 costs
Carbon dioxide costs
Ion exchange resin regeneration
VOCs
Maintenance material cost
UV/H2O2 units and air stripper
TFA was designed for 100 gpm,
but is currently operating at 300
gpm (see Section 2 for discussion
of influent concentrations); TFB
was designed for 100 gpm, and is
currently operating at 50 gpm
$146,000/year at TFA;
$70,000/year at TFB
$40,000/year at TFA;
$5,700/year at TFB
$0 at TFA;
$500/year at TFB
$0 at TFA and TFB
Destroyed onsite and collected
on GAC, which was regenerated
or disposed offsite
$15,000/year at TFA;
$9,000/year at TFB
Higher efficiency air stripper
360 gpm for TFA;
90 gpm for TFB
$45,000/year at TFA;
$14,500/year at TFB
$0 at TFA and TFB
$0 at TFA and TFB
$0 at TFA; $3,500/year at TFB
Collected on GAC and
regenerated or disposed offsite
$2,000 at TFA;
$1,000 at TFB
To minimize the time the treatment facilities would be shut down when removing the UV/H2O2
units and replacing them with large capacity air strippers, DOE/LLNL plan to construct the new air
strippers while the UV/H2O2 units are still operating. The facilities will then be shut down only to
switch over piping and wiring.
Table 2 presents a schedule for implementing equipment changes at TFA. Equipment changes
will occur at TFB as funding becomes available according to a schedule that will be presented to
the regulatory agencies at that time. After the new air strippers are activated, the UV/H2O2
equipment will be decommissioned and decontaminated as discussed in the Compliance Monitoring
Plan (Nichols et al., 1996), following the decontamination procedures in Standard Operating
Procedure 4.5 (Dibley and Depue, 1996).
4-97/ERD-l 25555 :rtd
-------
UCRL-AR-125555
Explanation of Significant Differences for
Treatment Facilities A and B, LLNL Liv. Site
April 1997
Table 2. TFA equipment replacement schedule.
Item
Order and receive air stripper
Construction
Electrical connections
Activation
Start
10-15-96
2-18-97
4-14-97
4-28-97
End
1-31-97
4-11-97
4-25-97
5-30-97
3.3. Summary
The benefits of the proposed remedy include the capability to remediate ground water at higher
flow rates, thus accomplishing ground water cleanup faster; use of a proven technology that
already exists at TFA, TFB, and all of the other LLNL treatment facilities, including Portable
Treatment Units; reduction of the use of hazardous material (H2O2); significant cost reduction; and
rapid return of investment on the capital equipment. The cost to replace the UV/H2O2 units at TFA
and TFB with air strippers is estimated to be $190,000 and $60,000, respectively. The investment
return on the capital equipment is estimated to be 1.2 years for TFA, and 0.9 years for TFB.
4. Support Agency Comments
The following responses address EPA comments dated December 10, 1996, and DTSC
comments dated December 4, 1996, on the Draft BSD, as presented in separate letters to DOE. No
comments were received from the RWQCB.
4.1. EPA Comments and DOE/LLNL Responses
Comment No. 1: Page 1, paragraph 2, sentence 1. Either change the phrase "The lead
agency..." to "The lead regulatory agency..." or change the "...U.S. Environmental Protection
Agency..." to the "...U.S. Department of Energy...".
This sentence now reads: "The lead regulatory agency...".
Comment No. 2: Page 3, paragraph 2, sentence 4. We believe this sentence should reference
levels ofPCE instead ofTCE. This would then be consistent with the preceding paragraph and the
Third Quarter Self-Monitoring Report of November 27, 1996.
The requested change has been made.
Comment No. 3: Page 6. In the second line, the phrase "...the EPA believes..." should be
changed to read "...EPA and DOE believe...". This is because both parties are signing this ESD.
The requested change has been made.
4-97/ERD-125555:rtd
-------
UCRL-AR-125555 Explanation of Significant Differences for April 1997
Treatment Facilities A and B, LLNL Liv. Site
42. DTSC Comments and DOE/LLNL Responses
Comment No. 1: Our review of the draft explanation of significant differences (ESD)
indicates that your proposed changes to the TFA and TFB treatment systems are not adequately
supported. Specifically, the draft ESD does not detail why the reasons that UV/oxidation was
originally chosen over air stripping in the ROD are no longer valid. On page Attachment A-57 of
the ROD, your response to comment A8j states that UV/oxidation was chosen because it has the
advantage of destroying most contaminants, converting them to harmless compounds. The draft
ESD indicates that only reason for the treatment change is economics.
As discussed during previous RPM meetings and during the August 1996 Community Work
Group meeting, DTSC is in support of your proposal. However, before we can approve it, the
ESD ]) must present the reasons why UV/oxidation was considered in the ROD; 2) indicate how
present conditions have changed since the ROD was signed; and 3) detail why the economic issues
now outweigh the contaminant destruction issues.
Section 3.1 of the ESD now includes a discussion of: (1) why UV/H2O2 was the preferred
original remedy, (2) VOC reduction over time, and (3) the benefits of the proposed
remedy.
Comment No. 2: Table 1 must include the additional cost of the GAC regeneration due to
the increased VOC loading. In addition, the GAC replacement rate, as detailed in Remedial Design
Document #7, is to be recalculated and included in the standard operating procedures for the two
treatment facilities.
GAC replacement frequency and costs will not increase due to the proposed remedy. Time
estimates for replacing the GAC (Boegel et al., 1993) were based on assumed initial
concentrations. However, over the last six years, the GAC effluent has always been below
BAAQMD's discharge limits and never necessitated GAC replacement. The GAC has been
replaced about once a year as part of routine maintenance. The GAC will change from one
200 pound unit to two 1,500 pound units (3,000 pounds total) to accommodate the
increased air flow rate. DOE/LLNL will continue to monitor the GAC effluent with an
organic vapor analyzer according to the schedule and requirements established by
BAAQMD. As soon as effluent concentrations begin to approach BAAQMD discharge
limits, the GAC will be replaced.
This discussion is included in Section 3.2 of the ESD.
Comment No. 3: The ESD should state that the UV/oxidation equipment will be
decommissioned and decontaminated as per the Compliance Monitoring Plan and SOP #4.5.
This is included in Section 3.2 of the ESD.
Comment No. 4: It is not clear how the changeover from UV/oxidation to air stripping will
take place. That is, there is a schedule for equipment replacement, but the ESD does not indicate
what this equipment replacement entails nor whether the existing facility will be shut down during
this replacement.
As discussed at the Remedial Project Managers' meeting on December 10, 1996, to
minimize treatment facility downtime, DOE/LLNL plan to construct the new air stripper
while the UV/H2O2 units are still operating. The facilities will be shut down only to switch
4-97/ERD-125555:rtd
-------
UCRL-AR-125555 Explanation of Significant Differences for April 1997
Treatment Facilities A and B, LLNL Liv. Site
over piping and wiring. DOE/LLNL anticipate that downtime may be up to two months for
each facility.
A discussion of this changeover is included in Section 3.2 of the BSD.
4.3. RWQCB Comments and DOE/LLNL Responses
None.
4-97/ERD-125555:rtd
-------
UCRL-AR-125555 Explanation of Significant Differences for April 1997
Treatment Facilities A and B, LLNL LAV. Site
5. Affirmation of the Statutory Determinations
Considering the new information and the changes that will be made to the proposed remedy,
the EPA and DOE believe that the remedy remains protective of human health and the environment,
complies with Federal and State requirements identified in the ROD as applicable or relevant and
appropriate to this remedial action, and is cost effective. In addition, the revised remedy utilizes
permanent solutions and alternative treatment technologies to the maximum extent practical for this
site.
,
Daniel Opalski ~ /'" tete
Chief, Federal Facilities Cleanup Branch
U.S. Environmental Protection Agency
Region DC
Janles Davis Date
/Associate Manager for Environmental Management
Oakland Operations Office
U.S. Department of Energy
4-97/ERD-125555:rtd
-------
UCRL-AR-125555 Explanation of Significant Differences for April 1997
Treatment Facilities A and B, LLNL Liv. Site
Referenees
Boegel, A. J., M. D. Dresen, E. Folsom, P. Thiry, J. P. Ziagos, L. L. Berg, and J. K.
Macdonald (Eds.) (1993), Remedial Design Report No. 1 for Treatment Facilities A and B,
Lawrence Livermore National Laboratory Livermore Site, Lawrence Livermore National
Laboratory, Livermore, Calif. (UCRL-AR-110576).
Dibley, V. and R. Depue (Eds.) (1996), LLNL Livermore Site and Site 300 Environmental
Restoration Project Standard Operating Procedures (SOPs), Lawrence Livermore National
Laboratory, Livermore, Calif. (UCRL-MA-109115 Rev. 2)
Dresen, M. D., J. P. Ziagos, A. J. Boegel, and E. M. Nichols (Eds.) (1993), Remedial Action
Implementation Plan for the LLNL Livermore Site, Lawrence Livermore National Laboratory,
Livermore, Calif. (UCRL-AR- 110532)(Page 43 revised September 2, 1993; Table 5 revised
July 2, 1996).
Isherwood, W. R, C. H. Hall, and M. D. Dresen (Eds.) (1990), CERCLA Feasibility Study for
the LLNL Livermore Site, Lawrence Livermore National Laboratory, Livermore, Calif.
(UCRL-AR-104040).
Lamarre, A. L. and P. Ko (1996), Letter Report: LLNL Livermore Site July 2, 1996 Remedial
Project Manager's Meeting Summary and Second Quarter Self-Monitoring Report, dated
August 29, 1996.
Nichols, E. M., L. L. Berg, M. D. Dresen, R. J. Gelinas, R. W. Bainer, E. N. Folsom, and A. L
Lamarre (Eds.) (1995), Compliance Monitoring Plan for the Lawrence Livermore National
Laboratory Livermore Site, Lawrence Livermore National Laboratory, Livermore, Calif.
(UCRL-AR-120936).
Thorpe, R. K., W. F. Isherwood, M. D., Dresen, and C. P. Webster-Scholten (Eds.) (1990),
CERCLA Remedial Investigation Report for the LLNL Livermore Site, Lawrence Livermore
National Laboratory, Livermore, Calif. (UCAR-10299 vols 1-5).
U.S. Department of Energy (DOE) (1992), Record of Decision for the Lawrence Livermore
National Laboratory, Livermore Site, Lawrence Livermore National Laboratory, Livermore,
Calif. (UCRL-AR-109105).
U.S. Environmental Protection Agency (EPA) (1991), Guide to Addressing Pre-ROD and Post-
ROD Changes, Office of Solid Waste and Emergency Response, Publication 9355.3-02, April
1991.
U.S. Environmental Protection Agency (EPA) (1992), Preliminary Draft Guidance on Preparing
Superfund Decision Documents, Office of Solid Waste and Emergency Response, Directive
9355.3-02, January 1992.
4-97/ERD-125555:rtd 10
L
-------
-------
------- |