WDEQ VOLUNTARY REMEDIATION PROGRAM
FULL-SCALE REMEDIATION WORK PLAN
HALLIBURTON FACILITY
44 LARY LOZIER ROAD
BOULDER, WYOMING
VRP # 58.136
REVISED JUNE 2012
Prepared for:
HALLIBURTON ENERGY SERVICES, INC.
Houston, Texas
WDEQ VOLUNTARY REMEDIATION PROGRAM
FULL-SCALE REMEDIATION WORK PLAN
HALLIBURTON FACILITY
44 LARY LOZIER ROAD
BOULDER, WYOMING
VRP # 58.136
REVISED JUNE 2012
Prepared for:
HALLIBURTON ENERGY SERVICES, INC.
10200 Bellaire Boulevard
P.O. Box 4574
Houston, Texas 77210-4574
Prepared by:
LT ENVIRONMENTAL, INC.
4600 West 60th Avenue
Arvada, Colorado 80003
(303) 433-9788
TABLE OF CONTENTS
1.0 INTRODUCTION ......................................................................................................................1-1
1.1
1.2
1.3
1.4
SITE DESCRIPTION AND BACKGROUND...................................................................1-1
PREVIOUS INVESTIGATIONS OR REMEDIATION ACTIVITIES .............................1-1
REGIONAL GEOLOGY AND HYDROGEOLOGY ........................................................1-3
SCOPE OF WORK .............................................................................................................1-4
2.0 SUMMARY OF ADDITIONAL LIMITED SITE CHARACTERIZATION ACTIVITIES ....2-1
2.1 SOIL INVESTIGATION ....................................................................................................2-1
2.1.1 Drilling Activities ....................................................................................................2-1
2.1.2 Soil Sampling Procedures and Analytical Results ..................................................2-2
2.2 GROUNDWATER INVESTIGATION ..............................................................................2-3
2.2.1 Monitoring Well Installation ...................................................................................2-3
2.2.2 Groundwater Sampling and Analysis ......................................................................2-3
2.3 QUALITY ASSURANCE/QUALITY CONTROL............................................................2-5
2.4 ECOLOGICAL EXCLUSION AND SCOPING ASSESSMENT .....................................2-5
3.0 SUMMARY OF PILOT STUDY ACTIVITIES ........................................................................3-1
3.1 SOIL TREATMENT LINER INTEGRITY TESTING ......................................................3-1
3.2 EXISTING SOIL STOCKPILE SAMPLING.....................................................................3-1
3.3 PILOT STUDY ACTIVITIES ............................................................................................3-2
3.3.1
3.3.2
3.3.3
3.3.4
Soil Treatment Area Construction ...........................................................................3-2
Excavation ...............................................................................................................3-2
Groundwater Management ......................................................................................3-4
Soil Treatment .........................................................................................................3-4
3.4 POST-PILOT STUDY GROUNDWATER MONITORING .............................................3-5
3.5 ADDITIONAL EXCAVATION ACTIVITES ...................................................................3-5
3.5.1 Justification for Additional Excavation ...................................................................3-5
3.5.2 Excavation ...............................................................................................................3-6
3.5.3 Soil Treatment .........................................................................................................3-6
3.6 QUALITY ASSURANCE/QUALITY CONTROL............................................................3-7
4.0 DATA QUALITY OBJECTIVES ..............................................................................................4-1
4.1
4.2
4.3
4.4
REMEDIATION OBJECTIVES.........................................................................................4-1
INSTITUTIONAL CONTROLS ........................................................................................4-1
ANALYTICAL DATA .......................................................................................................4-2
DATA QUALITY ASSURANCE PLAN ...........................................................................4-2
Full Scale Work Plan.doc
i
TABLE OF CONTENTS (CONTINUED)
5.0 FULL-SCALE REMEDIATION SCOPE OF WORK ...............................................................5-1
5.1
5.3
5.4
5.5
5.6
INJECTIONS ......................................................................................................................5-1
EXCAVATION ACTIVITIES ............................................................................................5-3
SOIL TREATMENT AREA MANAGEMENT AND MONITORING.............................5-4
SOIL ANALYTICAL METHODOLOGY .........................................................................5-5
GROUNDWATER MONITORING ...................................................................................5-5
5.6.1 Monitoring Well Installation ...................................................................................5-6
5.6.2 Groundwater Sampling and Analysis ......................................................................5-6
6.0 FULL-SCALE SOIL CONFIRMATION SAMPLING PLAN ..................................................6-1
6.1 CLEAN OVERBURDEN ...................................................................................................6-1
6.2 FULL-SCALE EXCAVATION AREA ..............................................................................6-1
6.3 SOIL TREATMENT AREA ...............................................................................................6-2
7.0 REPORTING AND SCHEDULING ..........................................................................................7-1
7.1
7.2
7.3
7.4
7.5
FULL-SCALE REMEDIATION SUMMARY REPORT ..................................................7-1
QUARTERLY GROUNDWATER MONITORING REPORTS .......................................7-1
SITE CLOSURE PLAN ......................................................................................................7-1
PROJECT COMMUNICATION ........................................................................................7-1
PROJECT SCHEDULE ......................................................................................................7-2
FIGURES
FIGURE 1
FIGURE 2
FIGURE 3
FIGURE 4
FIGURE 5
FIGURE 6
FIGURE 7
FIGURE 8
FIGURE 9
FIGURE 10
SITE LOCATION MAP
SITE MAP
SOIL BORING ANALYTICAL RESULTS
GROUNDWATER ELEVATION MAP
GROUNDWATER ANALYTICAL RESULTS
PLUME MAP AND PILOT STUDY AREAS
SOIL SCREENING ANALYTICAL RESULTS
PROPOSED FULL-SCALE REMEDIATION AREAS
PROPOSED MONITORING WELLS AND SOIL SAMPLES
PROJECT SCHEDULE
Full Scale Work Plan.doc
ii
TABLE OF CONTENTS (CONTINUED)
TABLES
TABLE 1
TABLE 2
TABLE 3
TABLE 4
TABLE 5
TABLE 6
TABLE 7
TABLE 8
TABLE 9
SITE CHARACTERIZATION SOIL ANALYTICAL RESULTS – TOTAL
PETROLEUM HYDROCABONS, METHANOL, AND BTEX
SITE CHARACTERIZATION SOIL ANALYTICAL RESULTS – PAHS
SITE CHARACTERIZATION GROUNDWATER ANALYTICAL
RESULTS – TOTAL PETROLEUM HYDROCABONS, METHANOL, AND
BTEX
SITE CHARACTERIZATION GROUNDWATER ANALYTICAL
RESULTS – PAHS
EXCAVATION AREA SUMMARY
PILOT STUDY SOIL SAMPLING ANALYTICAL RESULTS
DATA QUALITY OBJECTIVES
FULL-SCALE SAMPLING PARAMETERS AND METHODS
PROPOSED MONITORING WELL SAMPLING SUMMARY
APPENDICES
APPENDIX A
APPENDIX B
APPENDIX C
APPENDIX D
APPENDIX E
APPENDIX F
APPENDIX G
APPENDIX H
APPENDIX I
BORING LOGS
SITE CHARACTERIZATION ANALYTICAL DATA
ECOLOGICAL EXCLUSION ASSESSMENT AND THE ECOLOGICAL
SCOPING ASSESSMENT SUMMARY REPORT
PILOT STUDY ANALYTICAL DATA
DATA QUALITY ASSURANCE PLAN
SOIL TREATMENT CONSTRUCTION DIAGRAM
STANDARD OPERATING PROCEDURES FOR SOIL AND
GROUNDWATER INVESTIGATIONS
MATERIAL SAFETY DATA SHEETS
ENGINEERING CALCULATIONS FOR LINER
Full Scale Work Plan.doc
iii
1.0 INTRODUCTION
This Full-Scale Remediation Work Plan (Work Plan) presents the scope of work to conduct fullscale remediation to address petroleum hydrocarbon- and methanol-impacted soil and
groundwater at the Halliburton Energy Services, Inc. (Halliburton) facility (Site) located at 44
Lary Lozier Road near Boulder, Sublette County, Wyoming. This Work Plan summarizes the
limited additional site characterization conducted in June 2011 at the Site. A site location map
illustrating the location of the property on a United States Geological Survey topographic map is
presented as Figure 1, and a site map is presented as Figure 2. This Work Plan has been
developed using the Wyoming Department of Environmental Quality (WDEQ) Solid and
Hazardous Waste Division (SHWD) Voluntary Remediation Program (VRP) guidance
documents. The Site was accepted into the VRP on July 1, 2010 (VRP #58.136), after the
WDEQ determined the Site to be eligible for entry into the program according to Wyoming
Statute (W.S.) 35-11-1602(a)(i). A draft Remedy Agreement (RA) was prepared for the Site on
May 18, 2011. The RA was signed by Halliburton in June 2012 before beginning full-scale
remediation activities.
1.1 SITE DESCRIPTION AND BACKGROUND
The Site has historically been used as a maintenance and storage facility for oil and gas well
servicing equipment and chemicals. The potential contamination present includes gasoline, diesel
fuel, and methanol, which were stored in portable aboveground storage tanks (ASTs) in the
central portion of the Site. The ASTs and associated earthen berm containment have since been
removed from the Site. The ASTs were used by the former landowner, Wind River Oil Field
Services, prior to Halliburton purchasing the property in early 2010.
An engineered drainage ditch bisects the Site to the north of the former fueling center. The
drainage is a relocation of Sand Springs Draw whose original course was located farther to the
north. The Sand Springs Draw drainage channel runs east-west through the central portion of the
Site and has been armored and bermed to protect it during stormwater events. A map depicting
site details and the historical location of Sand Springs Draw is included as Figure 2.
1.2 PREVIOUS INVESTIGATIONS OR REMEDIATION ACTIVITIES
LTE completed a Phase I Environmental Site Assessment (ESA) in November 2008 and a
limited Phase II ESA in December 2008. Peak Environmental, Inc. (Peak) of Green River,
Wyoming, conducted a site investigation in April 2009 on behalf of the former landowner. LTE
conducted oversight of the Peak investigation on behalf of Halliburton. A report documenting
oversight activities was prepared in June 2009. In August 2009, Peak conducted a limited
excavation of three areas identified during the April 2009 site investigation. LTE provided
oversight of Peak’s excavation activities for Halliburton, and a summary of the activities is
provided in an October 2009 report. An additional subsurface investigation was conducted by
LTE in November 2009. Reports for each of the aforementioned assessments were included in
the VRP application.
The LTE reports summarizing the Phase I ESA and the Phase II ESA discuss LTE personnel’s
inability to inspect the underground storage tank (UST) associated with the wash bay in the
Full Scale Work Plan.doc
1-1
maintenance shop and two concrete vaults associated with the former fueling center. The wash
bay was inspected and was observed to be in good condition. The wash bay drains into an UST
that could not be inspected due to confined space entry issues. As a result, LTE installed soil
boring B-6, during the Phase II ESA, to evaluate the integrity of the UST and evaluate if the UST
was impacting subsurface media. The laboratory results for soil boring B-6, presented in the
December 2008 limited Phase II ESA, indicated the UST was not impacting subsurface media.
The location of soil boring B-6 is illustrated on Figure 2 of the Phase II ESA report. The UST
and wash bay are still present at the Site, however, are currently not in use.
During the 2008 limited Phase II ESA, the lids to the two fueling center concrete vaults were
unable to be opened to allow for visual inspection of vault integrity. Soil borings B-1 and B-3
were installed in the vicinity of the vaults to evaluate vault integrity, as depicted on Figure 2.
Samples were collected from the soil borings and analyzed for volatile organic compounds
(VOCs), total petroleum hydrocarbons-gasoline range organics (TPH-GRO), and total petroleum
hydrocarbons-diesel range organics (TPH-DRO). No concentrations of VOCs and TPH-GRO
were detected in the samples, and no detected concentrations of TPH-DRO (14.9 milligrams per
kilogram [mg/kg]) exceeded the soil VRP cleanup levels (2,300 mg/kg). In early 2009, all
portable ASTs associated with the former fueling center were removed when Wind River Oil
Field Services ceased operations at the Site.
During the 2008 limited Phase II ESA, eight soil borings were installed (B-1 through B-8) and
were analyzed for VOCs, TPH-GRO, and TPH-DRO. Additionally, the soil samples were
analyzed for polynuclear aromatic hydrocarbons (PAHs) if appreciable detections of TPH-DRO
were detected. Soil borings B-1 through B-6 were located in the vicinity of the former fueling
center. Only one sample (B-2) had concentrations detected exceeding VRP cleanup levels.
Detections of VOCs, including methyl ethyl ketone (MEK); PAHs, including naphthalene and 2methylnaphthalene; and TPH-GRO and TPH-DRO exceeded VRP cleanup levels. No additional
analytes were detected exceeding the VRP cleanup levels. The locations and analytical results of
these soil borings are depicted on Figure 3 of the Phase II ESA report.
The November 2009 subsurface investigation determined impact to soil and groundwater was
present at the Site in the vicinity of the former fueling center and downgradient (northwest) of
the former fueling center. Soil impact in excess of VRP allowable levels was present for
benzene, toluene, ethylbenzene, and total xylenes (BTEX) and methanol. Groundwater impact in
excess of VRP allowable levels was present for BTEX, methanol, TPH-GRO, and TPH-DRO.
The BTEX impact in groundwater appears to extend offsite to the northwest across James
Fairbanks Lane (Figure 6). Historical soil and groundwater analytical results were included in the
VRP application and are summarized in Tables 1 and 2.
Full Scale Work Plan.doc
1-2
Based on historical investigations, the constituents of concern for the Site include:
•
BTEX;
•
MEK;
•
Methanol;
•
TPH-GRO;
•
TPH-DRO; and
•
PAHs (naphthalene and 2-methylnaphthalene).
1.3 REGIONAL GEOLOGY AND HYDROGEOLOGY
Soils encountered during the November 2009 and June 2011 additional site investigations
consisted of alluvial brown, silty to clayey sand with sandy clay lenses from the ground surface
to approximately 9 feet to 15 feet below ground surface (bgs). Generally, below the silty to
clayey sand, claystone bedrock was encountered to the maximum depths explored of 15 feet to
20 feet bgs. The claystone bedrock was typically encountered closer to the ground surface in the
borings north of the Sand Springs Draw, while the claystone was encountered deeper to the south
of the Sands Springs Draw.
Black to grey staining and/or odor was observed in 27 of the 36 soil borings advanced during this
investigation. The staining was typically encountered in the smear zone above the groundwater
table and ranged from a few inches to several feet thick.
The static depth to groundwater ranged from 7.38 feet below top of casing (TOC) to 14.28 feet
below TOC during the November 2009 additional site investigation. The groundwater flow
direction was determined to be to the west at a gradient of 0.007 feet per foot. Groundwater
depths during the June 2011 additional site investigation are discussed in Section 2.2.2.
The hydraulic conductivity was calculated based on slug test data using the Bouwer & Rice
method and ranged from 1.03x10-4 centimeters per second (cm/s) to 1.16x10-4 cm/s. These
values are indicative of relatively low permeability and are consistent with the clayey sand and
sandy clay soils observed at the Site.
Soil samples collected from BH05 (8 feet to 10 feet bgs) and BH10 at (8 feet to 10 feet bgs) were
tested for parameters describing the physical characteristics of the subsurface materials within
the potential treatment zone at the Site. The specific gravity of the material ranged from 2.62
to 2.68. Gradation testing indicated the material from BH5 (8 feet to 10 feet bgs) consisted of
medium to fine grained sand that was slightly silty and the material from BH10 (8 feet to 10 feet
bgs) consisted of sandy clay. Permeability was 4.0x10-3 cm/s in BH5 and 1.9x10-6 cm/s in BH10.
These values are consistent with the soil types observed at the Site and the results of slug tests.
Full Scale Work Plan.doc
1-3
1.4 SCOPE OF WORK
This Work Plan provides the following:
•
The results of the additional limited site characterization conducted in
June 2011 (Section 2.0);
•
The results of the pilot study (Section 3.0);
•
Revised data quality objectives (DQOs) for full-scale remediation per Fact Sheets #28
and #29 (Section 4.0);
•
The details for full-scale remediation activities (Section 5.0), which are summarized
below;
•
A Soil Confirmation Sampling Plan per Fact Sheet #10, which is discussed in Section
6.0 of this plan; and
•
The reporting requirements and schedule (Section 7.0).
The Scope of Work (SOW) described in Section 5.0 of this Work Plan includes the following:
•
Expand the soil treatment area (STA) using a 15-mil (thousandths of an inch)
polypropylene liner and earthen berms. Ten inches of soil from the removal of clean
overburden in the excavation area will be placed on top of the liner to protect liner
integrity and serve as protective pad material;
•
Inject a carbon slurry/biological amendment into the groundwater located to the west
of the former AST area;
•
Excavate soil within the northern most methanol plume (Area B) and in the
comingled plume (Area A) as depicted on Figures 8 and 9 with the highest soil and
groundwater concentrations from the surface to 15 feet bgs. Dewatering of the
excavation area will be required as the highest concentrations were detected below
the top of the groundwater table. Confirmation sidewall samples will be collected;
•
Add BOS 200® and microbes to the bottom of the comingled excavation area
(Area A) and add microbes, capable of treating methanol, to the bottom of the
excavation area (Area B);
•
Segregate clean overburden soil (approximately ground surface to 10 feet bgs or
2,600 cubic yards) from the impacted soil (approximately 10 feet to 15 feet bgs or
1,300 cubic yards). A combination photo-ionization detector (PID) and flame
ionization detector (FID) will be used to screen the clean overburden. A screening
limit of 50 parts per million (ppm) will be used. The clean overburden soil will be
sampled at a rate of one sample per 200 cubic yards. The soil samples will be
analyzed as discussed in Section 6.0;
Full Scale Work Plan.doc
1-4
•
The impacted soil will be placed in the STA in windrows at heights no greater than 18
inches;
•
Pump groundwater from dewatering activities into temporary storage tank(s) on site;
•
Backfill the excavations with clean overburden to a depth of 10 feet bgs or less to
stabilize the sidewalls of the excavation. Temporary fencing will be used for safety
purposes until the excavated pilot study areas can be completely backfilled which will
occur after the impacted soil is remediated;
•
Turn over the impacted soil in the STA using a tractor and a pull-behind rototiller,
disk, or equivalent equipment weekly initially and subsequently to be adjusted based
on monitoring results;
•
Spray groundwater, removed during dewatering and collected in the temporary
storage tanks, onto the impacted soil in the STA periodically. The groundwater will
aid in biological degradation and provide dust suppression of the impacted soil during
treatment;
•
Monitor the groundwater within and surrounding the remediation areas to obtain site
closure;
•
Sample the soil in the STA periodically to monitor remediation progress; and
•
Inspect the liner for damage and collect confirmation soil samples underneath the
liner to confirm liner integrity.
Full Scale Work Plan.doc
1-5
2.0 SUMMARY OF ADDITIONAL LIMITED SITE CHARACTERIZATION
ACTIVITIES
The purpose of the additional limited site characterization was to obtain additional data to further
define the subsurface impacts for use during full-scale remediation activities and to determine
current groundwater conditions. The characterization activities included advancement and
sampling of soil borings, installation and development of monitoring wells, and sampling of
existing and new groundwater monitoring wells. The field work completed during the additional
limited site characterization and pilot study was conducted in accordance with the Health and
Safety Plan (HASP) developed specifically for this project. Deviations from the Pilot Study
Work Plan are discussed below.
2.1 SOIL INVESTIGATION
On June 8, 2011, a total of seven soil borings were advanced at the Site to further define the
methanol and comingled benzene and methanol plumes. An additional soil boring was advanced
to replace a destroyed monitoring well on site. The soil borings were advanced using a hydraulic
push drilling rig to allow for a detailed physical description of the soil present in the area and for
the collection of discrete soil samples for possible laboratory analysis. Prior to advancement of
soil borings, the Site was cleared for utilities by contacting the Wyoming One Call service and
using a private locating service.
2.1.1
Drilling Activities
Subsurface soil borings were advanced using hydraulic push techniques from the ground surface
to at least five feet below the apparent water table. A total of seven soil borings (BH37 to BH43)
were advanced at the Site (Figure 2). Two (BH37 and BH38) of the seven soil borings were
located on the north side of the northernmost methanol plume. Two additional soil borings
(BH39 and BH40) were located on the east side of the easternmost methanol plume. Two soil
borings (BH41 and BH42) were located to the west of the former fueling center. The seventh soil
boring (BH43) was installed downgradient of BH26 and BH29 to determine the extent of the
offsite benzene plume on the Flint River property. An additional soil boring was installed as a
replacement for monitoring well BH29 as this well was found to be destroyed. The attempted
installation of soil borings BH44 and BH45 were part of the pilot study activities and are
discussed in Section 3.1.
Soils encountered during the June 2011 additional site investigation were similar to previous
investigations and consisted of alluvial, silty to clayey sand with sandy clay lenses from the
ground surface to approximately 9 feet to 13 feet bgs. Below the silty to clayey sand, claystone
bedrock was encountered to the maximum depths explored of 12 feet to 14 feet bgs in most
borings. The claystone bedrock was typically encountered closer to the ground surface in the
borings north of the Sand Springs Draw, and the claystone bedrock was encountered deeper to
the south of the Sands Springs Draw. Boring logs are included as Appendix A.
Black to grey staining and/or odor was observed in four of the seven soil borings advanced
during the June 2011 investigation (BH37, BH38, BH40, and BH42). The staining was typically
Full Scale Work Plan.doc
2-1
encountered in the smear zone above the groundwater table and ranged from a few inches to
several feet thick.
The six soil borings were converted into groundwater monitoring wells as described in Section
2.2.1.
2.1.2
Soil Sampling Procedures and Analytical Results
Soil samples were collected continuously using disposable acetate sleeves in the lead sampler of
the hydraulic push drill string. Each sample was field screened using a PID/FID for the presence
of organic vapors. A split of each sample was placed in a sealed plastic bag for field screening.
After allowing the sample split to equilibrate, the PID/FID was used to measure the
concentration of organic vapors in the headspace of the bag. If visual evidence of impact or
indications of volatile constituents were encountered in a sample, a sample was collected from
the impacted zone and placed in a laboratory-supplied sample container. If more than one soil
sample collected during the installation of a soil boring exhibited impact, the worst-case sample
based on visual inspection and field screening, was submitted for analysis. If the soil boring had
no detections on the PID/FID and there was no visual evidence of impact, a soil sample was
collected at a depth immediately above the groundwater table. The soil samples were submitted
to Summit Scientific (Summit).
The highest concentration of organic vapors measured using the PID was recorded in soil boring
BH41 (12 feet to 14 feet bgs) at a concentration of 43.65 ppm. The highest concentration of
organic vapors measured using the FID was recorded in soil boring BH38 (12 feet to 14 feet bgs)
at a concentration of 309 ppm. The total volatile organic vapor concentrations measured in the
sample headspace using the PID/FID are listed on the boring logs in Appendix A. Visual or
olfactory evidence of impact was observed in four of the eight soil borings as described on the
boring logs in Appendix A.
The soil analytical results were compared to the WDEQ VRP migration to groundwater cleanup
levels. Benzene and ethylbenzene concentrations were not detected at concentrations in excess of
the cleanup level in the nine samples submitted for laboratory analysis. However, the laboratory
reporting limits for benzene and ethylbenzene (0.005 mg/kg) exceeded the cleanup level. No
other BTEX constituent concentration was detected exceeding its respective cleanup level. The
soil analytical results are depicted on Figure 3 and summarized in Tables 1 and 2. Laboratory
analytical data, chain-of-custody forms, and quality assurance/quality control (QA/QC)
information for the soil sampling are included in Appendix B. For future sampling events, which
will include the pilot test, ChemSolutions will be providing laboratory analytical services.
ChemSolutions was selected due to their ability to best match the WDEQ cleanup levels.
Analytical data will be reported between the reporting limit (RL) and the method detection limit
(MDL), and where necessary, the analytical results will be marked with a “J” flag.
Methanol was detected in five of the eight soil borings (BH38, BH38, BH40, BH41, and BH42)
at concentrations exceeding the cleanup level. The borings are located to the west of the pilot
study area A, and north of pilot study area B, and south of pilot study area C.
Full Scale Work Plan.doc
2-2
TPH-GRO and TPH-DRO were not detected above the laboratory reporting limit in soil borings.
Since TPH-DRO was not detected in the samples considered for PAH analysis, PAH analysis
was not completed for the eight soil borings.
2.2 GROUNDWATER INVESTIGATION
The purpose of the groundwater investigation was to define the horizontal extent of groundwater
impact at the Site and obtain current data on the existing groundwater conditions. The
groundwater investigation included the installation of groundwater monitoring wells in the seven
soil borings proposed to be advanced. Groundwater samples were collected from these seven
wells, one replacement well, and 20 selected existing monitoring wells and submitted for
laboratory analyses. The selected analytical methods were based on historical site use and
historical analytical results.
2.2.1
Monitoring Well Installation
Groundwater monitoring wells were installed using hydraulic direct-push drilling methods and
advanced to at least five feet below the observed groundwater table. A 10/20 silica sand pack
was placed in the annulus between the boring and the well casing from the total depth of the
boring to approximately two feet above the well screen. Bentonite crumbles were placed atop the
sand pack to ground surface and hydrated. The wells were completed with steel protective covers
set in concrete. The boring logs included in Appendix A contain a monitoring well completion
diagram. The location of each monitoring well was recorded using a survey-quality Global
Positioning System (GPS) unit. The TOC elevations were measured to an accuracy of +/-0.01
foot. A measuring point was marked on the north side of each casing. Monitoring wells were
constructed using 10 feet of factory-slotted 0.010 Schedule 40 polyvinyl chloride (PVC) screen.
Monitoring wells were developed, in accordance with VRP Fact Sheet #29, by purging a
minimum of three well casing volumes using one-quarter inch diameter high density
polyethylene tubing and a check-valve as detailed in Standard Operating Procedure (SOP) 11,
included in Appendix G. This method allows for the removal of more sediment than a narrow
gauge bailer can achieve and is an effective alternative when a submersible pump is not feasible
for developing 1-inch diameter monitoring wells. Monitoring wells were allowed to recover for a
minimum of 24 hours following development before groundwater sampling as described in
Section 2.2.2.
2.2.2
Groundwater Sampling and Analysis
Low-flow sampling techniques were used to collect groundwater samples from the seven new
monitoring wells, one replacement well, and 20 existing monitoring wells. The average purging
flow rate was 0.051 gallons per minute (gpm), which is within the acceptable range (0.026 gpm
to 0.132 gpm) suggested in the United States Environmental Protection Agency (EPA) guidance
document entitled Low-Flow (Minimal Drawdown) Ground-Water Sampling Procedures (April
1996). One monitoring well was sampled in April 2011 and 20 monitoring wells were sampled in
June 2011. New disposable polyethylene tubing was placed in each monitoring well to be
sampled using a peristaltic pump with the end of the tubing centered within the groundwater
column. The monitoring wells were sampled after purging three to five well casing volumes of
Full Scale Work Plan.doc
2-3
groundwater. Field parameters including temperature, pH, and specific conductance were
measured during purging activities.
During the April and June 2011 sampling events, the static depth to groundwater ranged from
6.45 feet below TOC to 13.33 feet below TOC. The groundwater flow direction was determined
to be to the west at a gradient of 0.008 feet per foot. Figure 4 illustrates relative groundwater
elevations measured in each of the sampled monitoring wells.
Development and purged groundwater was containerized in Department of Transportation
(DOT) approved 55-gallon steel drums and was treated at the STA during the pilot study (see
Section 4.0).The WDEQ has established Groundwater Cleanup Levels (GWCLs) for BTEX at 5
micrograms per liter (µg/L), 1,000 µg/L, 700 µg/L, and 10,000 µg/L, respectively, and for
methanol at 18,200 µg/L. The GWCLs for TPH-GRO and TPH-DRO are 7.3 milligrams per liter
(mg/L) and 1.1 mg/L, respectively. When naphthalene and/or 2-methylnaphthalene are below the
GWCL in groundwater along with the other chemicals of concern and no free product is present
on the groundwater table, then the GWCL for TPH-DRO is 10 mg/L. In April and June 2011,
benzene was detected exceeding the GWCL in the groundwater samples collected from BH10,
BH13, BH14, BH16, BH26, and BH41 at concentrations ranging from 5.9 µg/L to 8,000 µg/L.
Toluene (48,000 µg/L), ethylbenzene (4,100 µg/L), and total xylenes (24,000 µg/L) were
detected exceeding the respective GWCLs in the groundwater sample collected from BH10 only.
Reported BTEX constituent concentrations in the remaining groundwater samples did not exceed
the respective GWCLs.
Methanol concentrations were detected exceeding the GWCL in the samples collected from
BH03, BH04, BH06, BH13, BH31, and BH32 at concentrations ranging from 30,800 µg/L to
7,100,000 µg/L.
TPH-GRO was detected exceeding the GWCL in the sample collected from BH10 at a
concentration of 96 mg/L. TPH-GRO was not detected exceeding the GWCL in the remaining
samples analyzed during this investigation. TPH-DRO was detected exceeding the GWCL in
BH10, BH13, BH26, BH43, and MW1-09 during the June 2011 investigation with
concentrations ranging from 1.65 mg/L to 5.20 mg/L.
Groundwater samples from seven monitoring wells were analyzed for PAHs during the June
2011 investigation. The laboratory detection limits reported for dibenz(a,h)anthracene and
indeno(1,2,3-cd)pyrene exceeded the respective GWCLs. No other PAH constituents were
detected above the respective laboratory reporting limit or exceeding the associated GWCL in
the seven samples.
Groundwater analytical results for all analytes are summarized in Tables 3 and 4. Laboratory
analytical data, chain-of-custody forms, and QA/QC information for the groundwater sampling
are included in Appendix B.
The samples were only tested for analytes expected to be found in that area based on historical
investigation results. Groundwater analytical results are presented on Figure 5 and summarized
on Tables 3 and 4. The benzene and methanol isoconcentration contours have been updated
based on the recent sampling event and are depicted on Figure 6.
Full Scale Work Plan.doc
2-4
Laboratory analytical results for soil and groundwater samples collected during the June 2011
additional site assessment activities are included in Appendix B.
2.3 QUALITY ASSURANCE/QUALITY CONTROL
The analysis of matrix spike and matrix spike duplicate samples, trip blanks, equipment blanks,
rinsate blanks, laboratory control samples and laboratory surrogates indicated the laboratory
analyses were performed accurately and within acceptable limits. The QA/QC results are
presented in the laboratory reports included in Appendix B. The relative percent differences
calculated for blind duplicate sample pairs were within 30 percent (%) for groundwater samples,
and 50% for soil samples, as specified in the Data Quality Assurance Plan (DQAP) located in
Appendix E.
2.4 ECOLOGICAL EXCLUSION AND SCOPING ASSESSMENT
The Ecological Exclusion Assessment and the Ecological Scoping Assessment was completed by
Real West Natural Resource Consulting (Real West) on July 7, 2011, in accordance with VRP
Fact Sheet #14. Findings indicate a suitable habitat is lacking on the Site for threatened,
endangered, or candidate wildlife or plant species. Wildlife species expected on the Site are
primarily avian species that might fly over the area and roost on the structures within the Site.
Rodents, primarily mice and voles, could inhabit the buildings on the Site. The greater sagegrouse, a candidate species, is probably within the sagebrush habitat surrounding the industrial
complex. While there is contamination of soil and groundwater on the Site, it is doubtful it will
affect the sage-grouse since this species is expected to avoid the vicinity due to the high level of
human activity and disturbance. The report, prepared by Real West, is included as Appendix C.
Only Step 1: Ecological Exclusion Assessment was completed at the Site. Given the findings of
the Ecological Exclusion Assessment, it was unnecessary to proceed to Step 2: Ecological
Scoping Assessment.
Full Scale Work Plan.doc
2-5
3.0 SUMMARY OF PILOT STUDY ACTIVITIES
The purpose of the pilot study was to verify soil composting (or landfarming) technology is an
appropriate and applicable method for the remediation of benzene, TPH-DRO, and methanol.
More specifically, the pilot study allowed for the assessment of this technology while
incorporating site-specific factors like variations in soil composition, groundwater flux into
excavated areas, climate, and contaminant combinations. The pilot study results may be scaled
up so the costs and remediation schedule of the larger scale project may be determined. Pilot
study activities included excavation and treatment of soil impacted with comingled contaminants
(benzene, TPH-DRO, and methanol) and methanol only to a depth of approximately 15 feet bgs,
tilling of soil deposited in the STA, application of groundwater to the STA, field screening of
soil to determine remediation progress, and confirmation soil sampling in the STA to verify soil
was treated to within compliance cleanup levels. Additional excavation activities were approved
by the WDEQ VRP and completed in October 2011. Deviations from the Pilot Study Work Plan
are discussed below.
3.1 SOIL TREATMENT LINER INTEGRITY TESTING
As part of the activities to be completed during the June 2011 additional site assessment, LTE
had proposed the installation of two monitoring wells downgradient of the STA to be used to
verify liner integrity during the pilot study and full-scale remediation. On June 8, 2011, LTE
made three attempts to install 1-inch diameter monitoring wells BH44 and BH45 at the locations
indicated on Figure 3. Competent claystone was observed with the direct-push rig at three
locations at depths ranging from 1 feet to 3 feet bgs with refusal at approximately 7 feet bgs,
which indicates bedrock exists above the groundwater table in this portion of the Site. Neither
monitoring wells nor soil borings have been installed in this area during previous investigations.
Nearby monitoring wells (BH25 and BH30) have been dry during historical sampling events. In
order to provide data regarding STA liner integrity following the completion of full-scale
remediation activities, LTE proposes sampling existing monitoring wells MW3-09, BH24, and
BH26, and BH25 and BH30 if they are not dry and collecting soil confirmation samples from
below the liner during STA post-closure to confirm the STA has not impacted the groundwater.
Confirmation soil samples will be collected after inspecting the liner for damage as discussed in
Section 6.0. If significant impact to subsurface is encountered at depths approaching the
groundwater table, an auger drilling rig will be utilized to install monitoring wells into the
shallow bedrock.
3.2 EXISTING SOIL STOCKPILE SAMPLING
During the April 2011 sampling event, LTE discovered four large soil stockpiles were still
present and three historical excavations remained open at the Site. The stockpiles had been
marked with labeled wooden stakes, which allowed LTE to determine the stockpiles consisted of
clean overburden stored on tarps since the conclusion of 2009 excavation activities by Peak. To
evaluate the stockpiled soil concentrations, LTE collected 3-point composite samples at a rate of
one per 200 cubic yards from the existing stockpiles prior to the start of pilot study excavation
activities. Four existing stockpile samples were collected and screened using a PID/FID on July
25, 2011. Sample Stockpile #1 (Area C depicted on Figure 6) screened above the FID threshold
Full Scale Work Plan.doc
3-1
limit of 50 ppm. LTE determined the soil contained in stockpile #1 would be treated in the STA
and the sample was not submitted for laboratory analysis. Samples from soil stockpile #2,
stockpile #3, and stockpile #4, which were collected from Area A and Area B as depicted on
Figure 6, were screened and found to be below the threshold limit of 50 ppm. The soil samples
were subsequently submitted for laboratory analysis on July 25, 2011. Laboratory analytical
results indicated the existing stockpile samples submitted for analysis were below laboratory
detection limits for all analytes. The soil contained in the existing stockpiles near Area A and
Area B was used to backfill the historical excavation pits remaining open since Peak’s 2009
excavation activities.
3.3 PILOT STUDY ACTIVITIES
3.3.1
Soil Treatment Area Construction
The STA for the pilot study was constructed between July 25 and July 29, 2011. The top 8 inches
of surface soil across the proposed 85 foot by 190 foot area was scraped down and a portion of
the native material was used to build the berms to three feet high and approximately five feet
wide. An additional 10 inches of soil was scraped and stockpiled for use as clean padding on top
of the STA liner, as discussed below. The scraped area was grubbed and all sharp objects were
removed to prevent puncture of the liner. The final grade inside the STA was calculated to be
2%.
The STA was lined with eleven 12-foot by 100-foot rolls of 15-mil polypropylene liner on
July 28, 2011. The liner was installed cross-gradient (north-south) to the direction of surface
water flow with a 1.5 foot overlap between the sheets. Each up-gradient sheet was installed on
top of the subsequent downgradient sheet so liquid could not pass between the liner layers and
seep below the liner. The liner was sealed on top of the seams using butyl seal tape per the
revised manufacturer specifications. The liner encompassed the entire bermed area and was
extended up and over the tops of all berm walls.
A sump was constructed in the southwest corner of the STA. This location was selected due to
the natural gradient observed. The sump was constructed in the shape of a pie piece. The sump
was approximately two feet below the grade of the surrounding STA area, had a radius of
measuring approximately 15 feet, and a circular arc measuring approximately 24 feet. The sump
area was double lined with a polypropylene liner to ensure its integrity. An inspector from the
WDEQ VRP was on site during STA construction on July 27, 2011, and confirmed this revision
to the original STA construction plan was acceptable.
The remaining stockpiled soil from scraping activities was placed onto the STA liner in order to
protect the liner from tearing during soil treatment activities. The pad of clean material was
compacted to a thickness of 10 inches via multiple passes by heavy machinery. An access ramp
was installed over the berm near the northeast corner of the STA to allow equipment to enter the
STA without compromising the berm integrity.
3.3.2
Excavation
Pilot study excavations were conducted from July 26 to August 3, 2011. Petroleum hydrocarbon
impact was encountered at approximately 4 feet bgs in Pilot Study Area A (Figure 6) and a total
Full Scale Work Plan.doc
3-2
excavation depth of 14.5 feet bgs was achieved. Approximately 933 cubic yards of impacted soil
were removed from Area A and deposited in the STA. Methanol impact was encountered at
approximately 10 feet bgs in Pilot Study Area B (Figure 6) and a total excavation depth of 15
feet bgs was achieved. Approximately 185 cubic yards of impacted soil were removed from Area
B and deposited in the STA. Methanol impact was encountered at approximately 6 feet bgs in
Pilot Study Area C (Figure 6) and a total excavation depth of 14.5 feet bgs was achieved.
Approximately 126 cubic yards of impacted soil were removed from Area C and deposited in the
STA. Table 5 lists the dimensions of each excavation area and the total volumes of soil removed.
Many of the soil screening samples collected from the side walls and floors of the pilot study
areas were below laboratory detection limits for all analytes. The locations of the excavation soil
confirmation samples are illustrated on Figure 7 and the corresponding analytical results are
included on Table 6. Only four out of five sidewall samples proposed in the Pilot Study Work
Plan were collected. The text of the revised Pilot Study Work Plan stated that five soil samples
will be collected; however, Figure 9 only showed four. The field personnel used Figure 9 when
conducting field activities. During a conference call with the VRP on May 1, 2012, it was agreed
that soil confirmation sampling was not required in the excavation pits since the highest soil
impacts in the subsurface have been observed to be located in the saturated smear zone.
Side wall samples from Pilot Study Area B and Area C (SWB01, SWB02, SWB03, SWC03, and
SWC04) exceeded the cleanup level for methanol. Only one side wall sample (SWA02) slightly
exceeded the cleanup level for naphthalene at 0.00072J. The “J” flag (Table 6) on analytical data
means the analytical results was estimated and the reported value is between the MDL and the
RL. A review of this data indicated additional excavation in this area would be necessary to fully
remediate the Site. To maximize the remediation time available before cold weather moved into
the area and address concerns regarding the migration of remaining up-gradient impacts into the
remediated areas, an addendum for the Pilot Study Work Plan was prepared and additional soil
was excavated. Details on additional excavation activities are discussed in Section 3.5.
Floor samples FSB01, FSB02, and FSA05 exceeded the cleanup levels for methanol. Floor
sample FSA02 exceeded the cleanup level for naphthalene and floor sample FSA03 exceeded the
cleanup level for benzene and naphthalene. The floor samples were collected within the smear
zone and exceedances indicate impact to groundwater is still present. LTE expects the
groundwater in these areas will be treated by the carbon slurry and microbes applied to the
bottom of the excavations. Continued groundwater monitoring in this area will confirm
groundwater has been treated to within compliance of groundwater cleanup levels.
Prior to backfilling the pilot study excavation areas with clean overburden, groundwater was
removed with a pump and is discussed further in Section 3.3.3 below. Following dewatering, 350
pounds of activated carbon (BOS 200®) and 20 gallons of microbes were applied to the bottom
of Pilot Study Area A, 10 gallons of microbes were applied to the bottom of Pilot Study Area B,
and an additional 10 gallons of microbes were applied to the bottom of Pilot Study Area C. The
BOS 200® is a combination of activated carbon, sulfate, and nutrients designed to trap and
promote biological degradation of petroleum hydrocarbons. Material Data Safety Sheets
(MSDSs) are included as Attachment D.
Full Scale Work Plan.doc
3-3
3.3.3
Groundwater Management
Approximately 900 gallons of groundwater were pumped out of the pilot test excavations and
into a 500 barrel (21,000 gallon) tank. The stored water was sampled on August 10, 2011 and
sample Frac01 was analyzed for benzene prior to its application to the STA. Laboratory
analytical results indicated benzene at a concentration of 4.4 µg/L in the stored groundwater.
Since this concentration did not exceed the 50 µg/L threshold limit proposed in the Pilot Study
Work Plan, pre-treatment prior to application of the water to the STA was not required. The
stored water was gradually applied to the STA during operation and monitoring (O&M) events to
maintain STA soil moisture.
3.3.4
Soil Treatment
A total of 1,244 cubic yards of impacted soil was removed from the pilot study areas during the
initial excavation activities and deposited into the STA. An additional 389 cubic yards was
removed during additional excavation activities, which are discussed further in Section 3.5. The
maximum tiller depth achieved with the available equipment was approximately 10 inches.
Given this restriction, the maximum volume of soil treated at one time was 498 cubic yards and
it was necessary to treat the soil deposited into the STA in three 10-inch thick layers.
The first soil treatment event was completed on August 10, 2011. Tilling was completed for
approximately seven hours during each tilling event, which allowed for multiple soil turns, liquid
evaporation, and volatilization of soil contaminants. Two weekly tilling events were required to
treat the top 10-inch layer (Layer 1) of soil before PID/FID screening results indicated the three
randomly selected 3-point composite soil samples were in compliance with the 50 ppm threshold
limit. Composite samples S-4 (5 inches [”]), S-5 (5”), and S-6 (5”) were submitted for laboratory
analysis on August 22, 2011. Analytical results indicated TPH-DRO was detected in sample S-5
(5”) at a concentration of 27 mg/kg. This concentration is in compliance with the WDEQ VRP
soil cleanup level and no other detections were indicated for the soil confirmation samples. On
August 26, 2011, Layer 1 was removed from the STA to allow for tilling of Layer 2 below
Layer 1.
Similar results were achieved during pilot study treatment of Layer 2 and Layer 3, with two
weeks of tilling resulting in soil PID/FID screening results less than 50 ppm. Composite samples
S-7 (4”), S-8 (5”), and S-9 (6”) were collected from Layer 2 on September 14, 2011. Analytical
results indicated TPH-DRO was detected in sample S-9 (6”) at a concentration of 130 mg/kg.
This concentration was in compliance with the WDEQ VRP soil cleanup level and no other
detections were indicated in the soil confirmation samples. On September 22, 2011, Layer 2 was
removed from the STA to allow for tilling of Layer 3 below Layer 2. One 5-gallon bucket of
remaining AM-101 microbes from the excavation activities was applied during the first till of
Layer 3. Composite samples S-10 (6”), S-11 (6”), and S-12 (6”) were collected from Layer 3 on
October 11, 2011. No detections were indicated for the soil confirmation samples. On October
17, 2011, Layer 3 was removed from the STA. There was no definitive indication as to whether
the addition of microbes aided in more rapid remediation of contaminants in the STA soil.
Full Scale Work Plan.doc
3-4
3.4 POST-PILOT STUDY GROUNDWATER MONITORING
On September 14, 2011, groundwater monitoring was completed at select monitoring wells six
weeks after the conclusion of pilot study excavation activities. Methanol concentrations for
monitoring wells BH04 and BH06, located inside the pilot test Area B and Area C excavation
footprints, decreased from 140,000 µg/L and 215,000 µg/L, respectively, to non-detect levels.
Additionally, the methanol concentration for monitoring well BH03, located just downgradient
of Pilot Study Area C, decreased from 122,000 µg/L to non-detect.
Comparing the April/June 2011 groundwater sampling results to the September 2011
groundwater sampling results, the TPH-DRO concentration in monitoring well BH13 increased
from 1.95 mg/L to 44 mg/L, respectively, while the methanol concentration decreased from
7,100,000 mg/L to 5,400 mg/L, respectively. The TPH-DRO concentration detected at BH14
increased from 0.403 mg/L in June 2011 to 2.0 mg/L in September 2011. Additionally,
concentrations of PAH constituent dibenz(a,h)anthrazene were detected at levels exceeding the
GWCL in monitoring wells BH13 and BH14 in September 2011. The increase in TPH-DRO and
PAH is potentially caused from contaminants desorbing from soil into the groundwater, which
potentially occurred due to disturbance of the soil during excavation activities. Monitoring wells
BH31 and BH32 continued to indicate methanol concentrations exceeding the GWCL. The
results of the groundwater monitoring event of September 14, 2011, are summarized on
Tables 3 and 4.
3.5 ADDITIONAL EXCAVATION ACTIVITES
Based on observations and analytical results of the initial pilot study SOW, which are discussed
in more detail below, additional excavation activities were recommended. An addendum to the
Pilot Study Work Plan was submitted to the WDEQ on October 13, 2011 and was subsequently
approved on October 14, 2011. The additional excavation activities were conducted, as part of
the pilot study instead of during full-scale remediation activities, to maximize the remediation
time available before cold weather moved into the area and address concerns regarding the
migration of remaining up-gradient impacts into the remediated areas.
3.5.1
Justification for Additional Excavation
3.5.1.1 Pilot Study Area A
Additional excavation to the south of Pilot Study Area A was proposed after LTE discovered that
a concrete slab and sub-grade steel stormwater catch-basin, related to the former fueling area,
were still present at the property and was potentially a source of impact to soil and groundwater.
These structures were located upgradient of the pilot study area and there was concern that this
potential source may eventually migrate into the remediated area.
3.5.1.2 Pilot Study Area B
A groundwater sample collected from monitoring well BH32 on September 14, 2011 indicated a
methanol concentration of 39,000 µg/L, which exceeded the WDEQ GWCL of 18,200 µg/L. The
methanol concentration at this well during a June 9, 2011, sampling event was 111,000 µg/L.
This well is located directly down-gradient of Pilot Study Area B. Excavation around this
Full Scale Work Plan.doc
3-5
monitoring well was proposed and conducted to remove additional impacted groundwater and
apply microbes to the bottom of the excavation to aid in reduction of methanol groundwater
concentrations.
3.5.1.3 Pilot Study Area C
Additional excavation to the south of Pilot Study Area C was proposed due to soil analytical
results of sidewall soil samples SWC03 and SWC04, collected from the southwest and southeast
corners of Pilot Study Area C. The analytical results for these sidewall soil samples indicated
methanol concentrations of 130 mg/kg and 770 mg/kg, respectively, which exceeded the WDEQ
VRP Migration to Groundwater Cleanup Levels and indicated remaining methanol impact to soil
pore spaces and groundwater in the source area. These soil analytical results suggest that
elevated methanol impact remains south (up-gradient) of Area C and there was concern that this
potential source may eventually migrate into the remediated area.
3.5.2
Excavation
The additional excavation was completed on October 17 and 18, 2011. Approximate volumes of
impacted soil removed from Pilot Study Area A-2, Area B-2, and Area C-2 were 163 cubic
yards, 93 cubic yards, and 133 cubic yards, respectively. The dimensions of the additional
excavation areas are listed in Table 5. After the previously excavated 1,244 cubic yards were
treated and removed from the STA, the soil from the additional excavation activities were
deposited into the STA. Additional excavations were completed to 15 feet bgs and sample results
indicated the side wall and floor samples were non-detect for all analytes. The volume of soil
excavated was limited to the volume treated via tilling in a single layer when deposited into the
STA. The volume of groundwater accumulated in the additional excavations did not warrant
dewatering activities. Approximately five gallons of microbes were mixed into the accumulated
groundwater at the bottom of the excavations prior to backfilling. The additional excavation area
extents are indicated on Figure 6. The locations of all additional excavation soil confirmation
samples are illustrated on Figure 7, and the corresponding analytical results are included in
Table 6.
3.5.3
Soil Treatment
Weekly STA tilling of the additional soil was completed on October 19, 2011, and
October 27, 2011. Three 3-point composite soil samples S-13 (6”), S-14 (8”), and S-15 (8”) were
collected from the STA on November 3, 2011. Concentrations of BTEX, MEK, and TPH-GRO
were not detected in these soil samples. TPH-DRO was detected in sample S-15 at a
concentration of 51 mg/kg, which is in compliance with the WDEQ VRP soil cleanup level. The
laboratory analytical results indicated that methanol concentrations exceeding the soil cleanup
level for sample S-14 (77 mg/kg) and S-15 (160 mg/kg). The soil samples were not analyzed for
PAHs since the soil requires further treatment for methanol. LTE asserts the rapidly decreasing
temperatures had a significant effect on the efficiency of soil treatment via tilling. The soil
removed during additional excavation activities remained in the STA through the winter.
The remaining soil in the STA was sampled again in April 2012. TPH-DRO and PAHs
concentrations were below the VRP Migration to Groundwater soil standard in all three soil
Full Scale Work Plan.doc
3-6
samples. However, one soil sample had detections of methanol slightly above standards at 4.2
mg/kg. The soil will be sampled again for methanol only prior to removing the soil from the STA
for use as clean backfill.
Laboratory analytical results for samples collected during pilot study excavation activities,
excavation dewatering, STA soil treatment, post-pilot groundwater monitoring and additional
excavation activities completed in October 2011 are included in Appendix D.
3.6 QUALITY ASSURANCE/QUALITY CONTROL
The analysis of matrix spike and matrix spike duplicate samples, trip blanks, laboratory control
samples and laboratory surrogates indicated laboratory analyses were performed accurately and
within acceptable limits. The QA/QC results are presented in the laboratory reports included in
Appendix D. The relative percent differences calculated for blind duplicate sample pairs were
within 30% for groundwater samples, and 50% for soil samples, as specified in the DQAP
(Appendix E).
Full Scale Work Plan.doc
3-7
4.0 DATA QUALITY OBJECTIVES
The DQOs for the full-scale activities were established using VRP Fact Sheet #28. The six steps
in the DQO process are presented in Table 7. The table focuses on the systematic nature of
planning for data collection including activities and outputs for each of the steps. Decisions and
inputs are identified, study boundaries are defined, decision rules are presented, sources of
potential decision errors are discussed, and the sampling design is summarized.
4.1 REMEDIATION OBJECTIVES
On-site and off-site soil analytical data will be compared to the WDEQ VRP migration to
groundwater cleanup levels as the groundwater elevation at this Site is shallow. On-site and offsite groundwater analytical data will be compared to the groundwater cleanup levels based on
Fact Sheet #13.
4.2 INSTITUTIONAL CONTROLS
Soil Excavation Notification and a Groundwater Use Restriction institution controls (ICs) were
implemented as part of the RA. These ICs ensure the WDEQ will be notified prior to subsurface
activities occurring within the on-site VRP area. Additionally, the ICs ensure the WDEQ and
parties conducting subsurface activities will be updated on the current conditions of the soil and
groundwater at the Site. Based on an evaluation of the current analytical data, the WDEQ will
make a recommendation on how to conduct subsurface activities and on how contaminated
media should be managed. Annually or until the ICs are removed, a records search will be
conducted to verify ICs are effective and a summary of those activities relating to the ICs will be
provided to WDEQ.
As part of the RA, prior notification must be given to the WDEQ if the new water supply wells
are proposed to be constructed on the Site. No water supply wells shall be constructed on the Site
without prior consultation with the WDEQ. No Use Control Area restrictions are proposed at this
time; however, a decision regarding additional ICs will be made based on the results of the FullScale Remediation. The three existing water supply wells, currently used as a non-potable water
source are allowed to continue to be used as a non-potable water source under this RA.
If offsite groundwater contamination is not remediated to concentrations within compliance of
the WDEQ VRP Site-Specific Cleanup Levels within 3 years of completing the full-scale
remedy, Halliburton will work with Flint Energy Services, Inc. or the current property owner to
implement an IC for Groundwater Use Restriction. Given consistent evidence, discussed below,
that a continuous impact/pathway from the site source area to the offsite area (Flint River) of
impact may not exist, the offsite (Flint River) area impact may have resulted from Flint River or
a previous owner’s operations. Monitoring wells BH24, BH27, and BH28 located between the
dissolved phase hydrocarbon plume (BH16 and BH41) and the far west monitoring wells on the
Flint property (BH26, BH29R, and BH43) have historically been below cleanup standards for
petroleum hydrocarbons. Therefore, it is difficult to make a connection between the source area
and impacts historically observed in monitoring wells BH26, BH29R, and BH43. Based on
recent groundwater analytical data collected in June and September 2011, as shown on Table 3,
Full Scale Work Plan.doc
4-1
monitoring wells BH26, BH29R, and BH43 were below GWCLs for BTEX, TPH-DRO, and
TPH-GRO.
4.3 ANALYTICAL DATA
One important factor, in attaining quality data and meeting the DQOs, is selection of the project
analytical laboratory. LTE will contract with ChemSolutions, in Centennial, Colorado, for
laboratory analytical services on this project. Sample analyses will follow the Environmental
Protection Agency (EPA) and other standard methods.
Specific DQOs include the requirement that analytical data generated during full-scale
remediation activities be of sufficient sensitivity to allow for comparisons to the WDEQ soil and
groundwater cleanup levels listed in WDEQ Fact Sheets #12 and #13. In accordance with
WDEQ Fact Sheet #8, analytical laboratory reporting limits have been established at
concentrations as low as is achievable by the contract laboratory. As presented in Table 8, the
analytical methods to be used during full-scale remediation activities are capable of generating
sample quantitation limits within compliance of the cleanup levels required by WDEQ.
4.4 DATA QUALITY ASSURANCE PLAN
The DQAP, included as Appendix E, contains requirements relating to project-specific DQOs.
For the VRP full-scale remediation activities, the data should satisfy the VRP DQOs described
above and the objectives described in the DQAP. The ability of the data to meet the precision,
accuracy, representativeness, comparability, and completeness criteria outlined in the DQAP is
of particular importance.
Full Scale Work Plan.doc
4-2
5.0 FULL-SCALE REMEDIATION SCOPE OF WORK
The full-scale remediation strategy is designed to remediate impacted soil and groundwater to
concentrations in compliance with the WDEQ VRP cleanup levels. Groundwater will be
monitored after the activities have been completed in order to achieve four consecutive quarters
of analytical results in compliance with the WDEQ VRP cleanup levels. Soil underneath the
STA will be sampled after full-scale treatment has occurred to confirm no impact to subsurface
soil is present below the liner. The full-scale remediation SOW will include:
•
Excavation and dewatering in Area A and B where the highest concentrations of
methanol are observed;
•
Soil treatment of methanol-impacted soil;
•
Treatment of groundwater removed during excavation;
•
Injection of a biodegradation carbon slurry (BOS 200®) in the benzene groundwater
plume area to the west of the former ASTs;
•
Application of remedial amendments to the bottom of the excavation pit;
•
Backfill and compaction of excavation area with treated soil; and
•
Groundwater monitoring.
The locations of the full-scale remediation areas are depicted on Figure 8 along with the
methanol and benzene plumes in groundwater. Deviations from the Work Plan will be approved
by WDEQ, recorded in the field book, and summarized in the Full-Scale Remediation Summary
Report.
5.1 INJECTIONS
Downgradient benzene impact to groundwater will be addressed through a combination of an
activated carbon slurry injection program, as outlined in this section, and a source area
excavation, discussed below. Activated carbon slurry injections (BOS 200®) will be
accomplished in the area where benzene concentrations greater than 50 µg/L have been detected.
Areas on-site and off-site where benzene concentrations are less than 50 µg/L will be monitored
as up-gradient injections and source area excavations are expected to reduce the incoming flux of
contamination thereby reducing concentrations to these areas. A Permit by Rule for underground
injection control for the injection of BOS 200® will be obtained by the WDEQ Water Quality
Division prior to beginning injection activities and a copy will be provided to the VRP.
The injection program will consist of injecting BOS 200® in approximately 31 injection points
spaced on 10 foot centers. Approximately 50 pounds of BOS 200® will be injected into each hole
at three different intervals from 10 feet bgs to 15 feet bgs based on historical site investigation
results. The injection area is depicted on Figure 8. MSDSs for this amendment are included as
Appendix H.
Full Scale Work Plan.doc
5-1
5.2 SOIL TREATMENT AREA CONSTRUCTION
An air emissions waiver will be obtained from the Air Quality Division prior to beginning
treatment of soils in the STA and a copy will be provided to the VRP. The existing road base
(top 4 to 6 inches), where the STA will be expanded, will be scraped off and used as berm
material for the STA and excess material will be stockpiled for future site restoration and use as
a soil layer to protect the liner. The grubbing will serve to provide a flat surface and to remove
sharp objects from the STA. Additionally, the area will be scarified, compacted with equipment
tires, and graded to provide a smooth surface and to prevent sharp objects from damaging the
liner during construction and treatment.
The on-site STA will be expanded according to the STA specifications detailed on the
construction diagram presented in Appendix F and include:
•
The pilot study STA may be expanded to the north to approximately 290 feet by 190
feet or as needed to accommodate the excavated impacted soil. The expanded area
will be sloped at a minimum 2-inch drop per 4-foot length (approximately 4 percent
slope).
•
Berm walls will be constructed surrounding the expanded STA to approximately four
feet in width and three feet in height. The north berm wall will be constructed
following final placement of all petroleum hydrocarbon-impacted soil within the
STA.
•
A 15-mil polypropylene impervious liner will be installed in accordance with the
manufacturer installation specifications and in a manner that protects the integrity of
the liner. The liner will be installed such that the sheets have an approximate 1.5-foot
overlap. The liner will be sealed using butyl seal double-sided tape between the seams
with vapor bond tape on top of the seams as suggested by the manufacturer. The liner
will encompass the entire bermed area and will extend up and over the top of berm
walls. Engineering calculations were performed to determine a 15-mil polypropylene
liner is adequate, and the calculations are included in Appendix I.
•
Stockpiled soil generated during excavation of clean overburden will be placed as
protective pad material directly over the impervious liner. Additional clean
overburden will be replaced into the open excavations to the top of the groundwater
elevation.
•
A minimum of 10 inches of clean overburden soil will be installed in a manner that
prevents damage to the impervious liner by equipment, personnel, etc. LTE will
compact the 10 inches of clean material by passing equipment over the soil in three
passes before placing impacted soil on top. Heavy equipment will place soil using an
up-slope to down-slope direction. The bucket on the equipment will maintain a
minimum height of 10 inches above the liner to prevent tearing.
•
An additional 10 inches to 12 inches of impacted soil will be deposited and spread on
top of the protective pad material within the STA.
Full Scale Work Plan.doc
5-2
•
The corners that are difficult for the equipment to reach will be constructed with
additional clean soil to a minimum of 22 inches above the liner. The disking
equipment to be used, after all soil has been placed in the STA, will be capable of
reaching a depth of 10 inches to 12 inches.
•
An access ramp(s) will be installed over the berm material to allow equipment to
enter the STA without compromising the berm integrity.
5.3 EXCAVATION ACTIVITIES
The purpose of additional excavation is to remove high concentrations of methanol impacted
groundwater in the smear zone for treatment in the STA. Methanol does not readily sorb to soil
and does readily strip from groundwater. Therefore, excavation is necessary to remove
groundwater-laden soil in the smear zone where detected methanol concentrations have been the
highest. Additionally, removing groundwater from the excavation will help to decrease the
remaining high concentrations of methanol impacted groundwater.
The proposed excavation areas are depicted on Figure 8 and are extensions of Pilot Study Areas
A and B. Table 5 summarizes the estimated area, including proposed dimensions, and volume of
the full-scale excavation areas. Actual dimensions, areas, and volumes will be summarized in the
Full-Scale Summary Report. Area A has been added due to groundwater analytical results from
an April 2012 sampling event. The groundwater sample results for monitoring well BH13R
indicated a methanol concentration (1,100,000 ug/L) exceeding the groundwater cleanup level
(18,200 ug/L). The excavation around former Pilot Study Area B is subject to adjustment
pending May 2012 groundwater monitoring results. Groundwater samples collected in April
2012 indicate that methanol is no longer present at concentrations above the cleanup level;
however, the groundwater table had decreased approximately 1 foot compared to September
2011. Soil will be removed in the excavation area from the surface to 15 feet bgs (bedrock). Two
separate soil stockpiles will be constructed; one for clean overburden and one for soil requiring
further treatment.
Based on the pilot study activities, contaminated soil was encountered in Pilot Study Area A at 4
feet bgs and Pilot Study Area B at approximately 10 feet bgs. Therefore for full-scale excavation
activities, soil removed from the surface to 4 feet bgs for Area A and surface to 10 feet bgs for
Area B is considered to be clean overburden, and this soil is available for use as clean backfill
without further treatment. It is assumed that soil removed from below 4 feet from Area A and 10
feet from Area B will require soil treatment before the soil can be used as backfill. The assumed
clean overburden soil will be stockpiled separately from soil assumed to need additional
treatment. A combination PID/FID will be used to screen the clean overburden. A screening limit
of 50 ppm will be used. The clean overburden soil will be sampled at a rate of one sample per
200 cubic yards as discussed in the Soil Confirmation Sampling Plan (Section 6.0) and will only
be used as clean backfill after the laboratory results indicate that the soil is clean. After the soil
has been treated, confirmation soil samples will be collected from the STA and submitted to the
laboratory for analysis before use as clean backfill on site. LTE understands if laboratory results
exceed the soil cleanup levels set forth by the VRP, additional remediation of the soil in the STA
may be necessary.
Full Scale Work Plan.doc
5-3
Safety fencing will be used to encircle excavated area exceeding 12 inches in depth for the
duration of the soil treatment project. All utilities will be located prior to commencing
excavation activity. Side sloping of the excavations will be conducted, as needed, to protect the
excavation and to provide safe working conditions in the excavation in accordance with current
state and federal Occupational Safety and Health Administration (OSHA) regulations.
Groundwater at the Site ranges from 7 feet to 12 feet bgs. Excavations may require dewatering to
allow for removal of soil at or below the groundwater table. Groundwater collected during
dewatering will be placed in tanks on site for treatment or application to the STA. The
groundwater will be applied to the STA in a manner to prevent groundwater from being sprayed
or carried outside the containment area. While the shallowest soil dries and methanol is
volatilized, the more saturated soils, deeper in the compost pile can be treated by promoting
biological activity. This can be accomplished more readily by keeping these soils moist and by
applying a constant food source (e.g., the methanol-impacted groundwater).
Amendments such as BOS 200® and microbes will be applied to the bottom of the excavation in
Area A, where benzene and methanol are comingled, to further treat the residual benzene and
methanol in the groundwater. MSDSs for these amendments are included as Appendix H. These
amendments will be applied using a backhoe. Microbes will be applied to the bottoms of the
excavation in Area B to further treat the residual methanol in the groundwater. For BOS 200®, a
50-lb bag of amendment will be placed within every 400 square feet of open excavation.
Microbes will be applied at a rate of 1 gallon per 100 square feet.
Sampling of the excavation side walls and bottom will be conducted during full-scale
remediation activities for screening purposes and to aid in the decision-making process to
determine if sufficient soil area has been exposed for treatment.
5.4 SOIL TREATMENT AREA MANAGEMENT AND MONITORING
The on-site STA will be managed according to the following management procedures.
1. The impacted soil within the STA shall be turned over on a weekly basis to aerate the
soil, promote aerobic degradation, and volatilize the petroleum hydrocarbon/methanol
constituents present in the soil. The soil will be turned over using a tractor and a
standard pull–behind rototiller, disk, or equivalent equipment reaching a 1-foot depth.
LTE anticipates it will take approximately two months to compost the soil depending
on weather conditions.
2. LTE will examine the sump after fluid applications and rain events and will pump out
water accumulating to a height of greater than 6 inches. If the soil on top of the cell is
dry, LTE will spray the pumped water onto the STA for treatment as discussed above.
If the soil is saturated, the water will be stored in a temporary storage tank pending
future application to the STA.
3. In addition to providing oxygen by turning the soil, the STA will be managed to
optimize moisture content, pH, microbial activity, and nutrient levels such that the
rate and extent of microbial biodegradation is increased. Hydrocarbon degrading
microbes, moisture, nutrients, and/or minerals may be added to enhance the efficiency
Full Scale Work Plan.doc
5-4
of microbial biodegradation. Specifically, amendments to the impacted soil may
include cultured facultative microbe concentrate, agricultural fertilizer, chicken litter,
horse manure, straw, lime, elemental sulphur, and/or other suitable alternatives.
4. Weekly PID/FID screening will be completed and confirmation soil samples will be
collected when screening results indicate soil remediation has been achieved.
Confirmation soil samples will initially be analyzed for methanol only, but will be
analyzed for BTEX, TPH-GRO, TPH-DRO, and MEK before being used a clean
backfill. Section 6.0 discusses the Soil Confirmation Sampling Plan. Monitoring of
microbial populations and moisture content may need to be conducted depending on
field observation and analytical results. Samples will be collected from the vertical
center of the soil. Soil samples will be collected at a rate of one sample per 200 cubic
yards during full-scale operations.
5. After evidence suggests free fluids have evaporated and the soil on top of the liner in
the soil treatment facility is remediated to concentrations in compliance with WDEQ
VRP levels, the soil above the liner will be removed and used as clean fill.
6. Following final use of the STA, the impervious liner will be removed from the STA
and properly disposed of as solid waste. Sampling under the liner will be conducted
to verify liner integrity, which is discussed in Section 6.0. If significant impacts to the
subsurface are encountered, additional investigation may be needed to determine
possible impacts to groundwater. The restoration of the area utilized for soil treatment
will be conducted in a manner to minimize erosion and to control sediment. The area
will be restored to its previous condition.
7. The surface of the excavation area will be returned to original conditions.
LTE understands if the soil or groundwater under the STA is found to be impacted due to soil
treatment activities, the impacted media will be remediated by LTE to the cleanup levels set forth
by the VRP.
5.5 SOIL ANALYTICAL METHODOLOGY
Soil samples will be submitted to ChemSolutions for analyses as described in previous sections
and in the Soil Confirmation Sampling Plan discussed in Section 6.0. Groundwater monitoring is
discussed below. Laboratory methods will follow standard EPA Test Methods as discussed in the
DQAP. Analytical parameters and methods are presented in Table 8.
5.6 GROUNDWATER MONITORING
The purpose of groundwater monitoring is to determine the effect of the full-scale remediation
activities. LTE expects up to four additional monitoring wells, outside of the original pilot study
area, will be removed during the excavation activities and proposes to install one additional
monitoring well to monitor the full-scale excavation area (Figure 9). The location of proposed
additional monitoring well (BH46) is subject to adjustment pending the results May 2012
groundwater analytical results. The monitoring wells will be installed and groundwater samples
will be collected from up to 33 monitoring wells, including eight replacement monitoring wells
Full Scale Work Plan.doc
5-5
and two newly installed monitoring wells, within the vicinity of the excavations and submitted
for laboratory analyses (Table 9) approximately six weeks after excavation completion.
Groundwater samples will continue to be collected quarterly until four consecutive quarters of
analytical data are in compliance with the WDEQ VRP cleanup levels.
5.6.1
Monitoring Well Installation
Factory-slotted 0.010 Schedule 40 PVC well screen and PVC riser piping will be inserted into
the excavations during backfilling operations to replace groundwater monitoring wells. The well
screen will be wrapped in a geofabric to reduce infiltration of fines during groundwater sampling
activities. These monitoring wells will be installed, developed, and sampled in the same manner
as the pilot study discussed in Section 2.2.1 of this report.
The location of each monitoring well will be recorded using a survey-quality GPS unit. TOC
elevations will be measured to an accuracy of +/- 0.01 feet. The measuring point will be marked
on the north side of each casing. Monitoring wells will be developed 24 hours after installation
by purging a minimum of 10 well casing volumes using a disposable bailer.
5.6.2
Groundwater Sampling and Analysis
The groundwater samples will be inspected for the presence of an iridescent sheen and/or odor
and the observations will be recorded in the field log book. The groundwater samples will be
collected using low-flow sampling methods after water quality parameters have stabilized. Field
parameters consisting of temperature, pH, oxidation-reduction potential, turbidity, and specific
conductance will be measured during purging activities. New disposable polyethylene tubing
will be placed in each monitoring well to be sampled using a peristaltic pump with the end of the
tubing centered within the groundwater column. Groundwater samples will be collected per SOP
13 in Appendix G and analyzed using the EPA methods detailed in Table 8. All samples will be
immediately placed in laboratory-provided containers, then in an insulated cooler filled with ice
and submitted under strict chain of custody to ChemSolutions for analysis. Table 9 summarizes
the monitoring wells to be sampled and for which analytes. The list of analytes includes BTEX,
methanol, TPH-GRO, TPH-DRO, and PAHs (SIM Method); however, not every monitoring well
will be analyzed for all of these analytes. If PAHs are in compliance with groundwater cleanup
levels after the first quarter of groundwater sampling, PAHs will be removed from the analytical
suite. MEK has been removed from the analytical suite as this analyte was not detected during
the June 2011 and September 2011 sampling events. MEK was historically only detected in soil.
Monitoring wells BH13 and BH31 will be sampled one time for barium and lead using low-flow
methods. LTE believes that the exceedances for these constituents observed in 2009 may have
been attributed to the wells not being developed prior to sampling as low water yield was
anticipated. If barium and lead are observed to exceed the cleanup standards, LTE and
Halliburton will discuss how to proceed with the VRP.
Purged groundwater will be containerized in DOT approved 55-gallon steel drums and either
treated at the STA, treated on site, or disposed of at an offsite licensed and approved disposal
facility depending on whether the STA is still in use.
Full Scale Work Plan.doc
5-6
6.0 FULL-SCALE SOIL CONFIRMATION SAMPLING PLAN
Prior to backfilling the excavated area, confirmation samples will be collected from segregated
clean overburden and in the STA. Sampling will be conducted in accordance with the WDEQ
SHWDs Interim Guidance on the Management of Petroleum Contaminated Soils at VRP Sites
and the DQAP included as Appendix E. DQOs are summarized in Section 4.0.
6.1 CLEAN OVERBURDEN
As previously discussed in Section 5.3, two separate soil stockpiles will be constructed. Based on
the pilot study activities, contaminated soil was encountered in Pilot Study Area A at 4 feet bgs
and Pilot Study Area B at approximately 10 feet bgs. Therefore for full-scale excavation
activities, soil removed from the surface to 4 feet bgs for Area A and surface to 10 feet bgs for
Area B is considered to be clean overburden, and this soil is available for use as clean backfill
without further treatment. It is assumed that soil removed from 4 feet to 15 feet bgs in Area A
and 10 feet to 15 feet bgs in Area B will require soil treatment before the soil can be used as
backfill. The assumed clean overburden soil will be stockpiled separately from soil assumed to
need additional treatment.
A combination PID/FID will be used to screen the clean overburden. A screening limit of 50
ppm will be used. The clean overburden soil will be sampled at a rate of one sample per 200
cubic yards. This protocol for verifying clean fill follows the WDEQ SHWDs Interim Guidance
on the Management of Petroleum Contaminated Soils at VRP Sites dated October 26, 2010.
Stockpiled soil from the comingled plume (Area A) will be sampled and analyzed for BTEX,
MEK, methanol, TPH-GRO, TPH-DRO, and PAHs before using the clean overburden soil as
backfill. PAHs will be analyzed using the selective ion monitoring (SIM) method only if TPHDRO is detected. Stockpiled soil from the methanol-only plume (Area B) will be sampled and
analyzed for methanol before using the clean overburden soil as backfill.. LTE understands if the
laboratory results exceed the soil cleanup levels set forth by the VRP, additional remediation of
the soil may be necessary.
6.2 FULL-SCALE EXCAVATION AREA
As depicted on Figures 8 and 9, the full-scale remediation program includes two excavation
areas and one injection area. The approximate dimensions, area, and volume of the excavation
area are summarized in Table 5. The estimated full-scale remediation area around Pilot Study
Area B may be adjusted pending May 2012 groundwater monitoring results as discussed in
Section 5.3. The main reason for excavating additional soil is to access the groundwater for the
removal of impacted groundwater and application of microbes. Floor and sidewall confirmation
samples will not be collected during full-scale excavation activities due to shallow groundwater;
however sidewall samples will be collected and used for screening purposes for determining the
extent of the excavations. The highest concentrations of COCs have historically been found in
the smear zone where soil is saturated with groundwater. Seven sidewall screening soil samples
will be collected in Area A and four sidewall screening soil samples will be collected in Area B
as depicted on Figure 9. The results of these soil screening samples will be used to assess the
need for additional excavation to gain access to the groundwater. The results will be summarized
Full Scale Work Plan.doc
6-1
in the Full-Scale Remediation Summary Plan. Groundwater will be monitored quarterly from onsite monitoring wells to verify the groundwater impact has decreased to within compliance of
groundwater levels.
The appropriate excavation extent will be determined through visual and olfactory observations
and by screening grab samples collected from the side walls and floor of the excavation with a
PID/FID. All soil screening samples will be collected from between 10 and 15 feet bgs and will
be transferred by hand from the excavation equipment bucket to an unused, sealable plastic bag
using new nitrile gloves for each sample. When measuring the level of methane volatilization
from soil, a screening limit of 50 ppm will be used to determine the location of all five
excavation extents. All visual observations, PID/FID readings, and screening sample locations
will be recorded in a field book.
6.3 SOIL TREATMENT AREA
As previously discussed in Section 5.5, soil treated on top of the liner in the STA will be sampled
and analyzed for BTEX, MEK, methanol, TPH-GRO, and TPH-DRO when weekly PID/FID
screening results indicate soil remediation has been achieved. The soil samples will not be
analyzed for PAHs (SIM Method) until final sampling. Monitoring of microbial populations and
moisture content may need to be conducted depending on field observation and analytical results.
Samples will be collected from the vertical center of the soil pile at a rate of one 3-point
composite sample per 200 cubic yards during full-scale operations. This protocol for verifying
clean fill follows the WDEQ SHWDs Interim Guidance on the Management of Petroleum
Contaminated Soils at VRP Sites dated October 26, 2010.
As previously stated in our response to comments, dated October 15, 2010, on the Pilot Study
Work Plan, after the excavated soil has been treated in the STA in compliance of the WDEQ
VRP cleanup levels and returned to the excavation pits, the liner will be inspected for damage,
removed, and properly disposed of as solid waste. Eight evenly spaced soil sample locations will
be field screened with a PID/FID and if the soil headspace is greater than 50 parts per million
(ppm), an individual sample will be collected and laboratory analyzed. The soil will be inspected
for possible liner leak locations, especially along the former liner seam locations. The liner
seams will be located using GPS prior to removal. If evidence of leakage is observed, soil
samples will be field screened and sampled for laboratory analysis according to the above
protocol. Samples will be analyzed for TPH-GRO, TPH-DRO, BTEX, and methanol. The
samples will be analyzed for PAHs if detections of TPH-DRO are present. At a minimum, four
soil samples will be collected and laboratory analyzed in accordance with the VRP residential
criteria for sampling every 1/5 acre.
Full Scale Work Plan.doc
6-2
7.0 REPORTING AND SCHEDULING
The activities conducted during the full-scale remediation efforts will be summarized in the FullScale Remediation Summary Report. A summary of the reports still requiring submittal by LTE
are described below. To date, LTE has submitted the VRP application which has been accepted
into the program, and LTE submitted the Site Investigation Report with the June 2010 VRP
application. The Site Investigation Report summarized the results of the 2008 limited Phase II
ESA. The initial public notice period was completed on September 16, 2010. A Public
Participation Plan (PPP) was required and was submitted in February 2011. The WDEQ VRP
submitted a draft RA on May 18, 2011. A public meeting was held on May 24, 2011, to discuss
historical site characterization conducted at the Site and the proposals for remediation. A public
notice for the RA was published in the Sublette Examiner from May 10 through May 31, 2011.
Letters to the contiguous landowners were prepared and submitted on May 25, 2011. The RA
public notice period ended on June 30, 2011. The RA is expected to be finalized by June 2012.
7.1 FULL-SCALE REMEDIATION SUMMARY REPORT
LTE will submit a Full-Scale Remediation Summary Report after the full-scale remediation
activities are complete. The Full-Scale Remediation Summary Report will discuss the
remediation activities conducted and confirmation sampling analytical results for both the
proposed excavation area and the soil treatment facility.
7.2 QUARTERLY GROUNDWATER MONITORING REPORTS
Groundwater monitoring reports will be prepared and submitted quarterly following sampling
events. The reports will be submitted quarterly until four consecutive quarters of groundwater
analytical results in compliance with the WDEQ VRP cleanup levels are achieved.
7.3 SITE CLOSURE PLAN
The Site Closure Plan will summarize the full-scale remediation activities, including STA
closure activities, and groundwater analytical results. The Site Closure Plan will request a
Certificate of Completion. The Site Closure Plan will provide, in accordance with the VRP Fact
Sheet #18, sampling and analysis results and discuss deviations from this Work Plan. The results
will provide evidence cleanup levels have been achieved at points of compliance, in accordance
with the guidelines for confirmation sampling. The Site Closure Plan will document the Site has
been restored to its initial surface condition.
7.4 PROJECT COMMUNICATION
LTE will provide regular status updates via e-mail to the VRP as to the progress of remediation
activities, additional site characterization activities, if necessary, and report preparation to
demonstrate the DQOs are being met and the project is progressing. LTE will continue to send
out quarterly e-mails to interested parties listed in the PPP.
Full Scale Work Plan.doc
7-1
7.5 PROJECT SCHEDULE
Full-scale remediation activities will begin as soon as practicable upon WDEQ approval of the
proposed Work Plan. LTE has tentatively scheduled this work to begin in June 2012. Completion
of all field work is dependent upon weather conditions, subcontractor availability, and site
access. Figure 10 outlines the project schedule as of May 23, 2012. The Full-Scale Remediation
Summary Report is tentatively scheduled for submittal to the WDEQ in November 2012.
Full Scale Work Plan.doc
7-2