Use of Direct Push Techniques, Membrane Interface Probe, and Colorimetric Test Kits for Solvent Plume Delineation at
Hurlburt Field, Site ST-123, Florida
Triad Elements Used
- Systematic Planning
- Real-Time Measurements
- Dynamic Work Strategies
Table of Contents
- Site Information
- Project Information
- Triad Approach Information
- Supporting Information
- Use of high-resolution, field-based innovative technologies to make real-time decisions during site characterization activities.
- Statistical correlations developed between innovative field-based analysis methods and proven fixed-base laboratory analysis methods.
- Development of a high-resolution dynamic work strategy (DWS) work plan based on precise decision logic achieved through systematic project planning (SPP).
- Site closure eminent within 10 months after the initiation of the Triad-based high-resolution site investigation.
In the Spring of 2004, the U.S. Air Force (USAF) instituted the Florida Triad Initiative at three active installations representing different major commands. Under the direction of the Air Force Special Operations Command (AFSOC), Hurlburt Field selected a Site Investigation (SI) and exit strategy for site closure at site ST-123 to implement the Triad Approach.
Volatile organic compounds (VOCs) were discovered in groundwater at the site in the mid-1990s. A number of investigations and treatment activities occurred between that time and the initiation of the Triad Initiative in June 2004. At the outset of the Triad activities, considerable uncertainty existed concerning the location of the sources of the VOCs, the hydrostratigraphic system, and the distribution of VOCs in that system.
Systematic project planning (SPP) for the investigations began in June 2004 and included a work plan that used a DWS and real-time instrumentation, which culminated in initiation of field activities in October 2004. A risk assessment and Statement of Basis were underway in April 2005. Highlights of the project from the Triad perspective include:
- Development of a Conceptual Site Model (CSM) based on available information.
- SPP aimed at development of an exit strategy and minimization of decision uncertainty. Primarily, the optimal exit strategy was to achieve maximum contaminant levels (MCLs) everywhere in the aquifer. Recognizing that there was a distinct possibility that the optimal condition would not be met, alternative outcomes were described where some level of land use controls would be required to eliminate the potential for exposure.
- Use of statistical methods to correlate the results of field-based innovative technologies with fixed-base laboratory analysis techniques allowed for quick and accurate contaminant delineation.
- Development of decision logic that guided the DWS toward minimization of decision uncertainty, providing a clear pathway to an exit strategy. During the SPP sessions, the decision uncertainty was prioritized into high, medium, and low categories. Decision logic was developed to guide a DWS to reduce decision uncertainty to an acceptable level and provide a clear path for an exit strategy. The DWS included combinations of innovative technologies that allowed for contingencies in case a given technology did not perform as expected.
- Experienced field management personnel with a clear understanding of the decision logic were equipped to implement the DWS smoothly and efficiently. Informed field managers were able to make data collection decisions that contributed to the greatest reduction of residual decision uncertainty as monetary resources diminished.
- Data management and dissemination through the use of a ftp site and daily emails ensured that stakeholders were informed and up-to-date on daily project activities. Periodically, graphical programs were used to develop revised CSMs, which were disseminated to stakeholders.
1. Site Information
||Hurlburt Field, Site ST-123
||Hurlburt Field, FL
- Aboveground Storage Tank
- Contaminated Aquifer - Contamination Source Unknown
- Federal Facility
- Gasoline Service Station/Petroleum Storage Facility
- Petroleum, Oil, Lubricant (POL) Line
|Project Lead Organization
||U.S. Air Force Special Operations Command (AFSOC)
|Project Lead Type
||U.S. Air Force Lead
|Regulatory Lead Program
||RCRA Corrective Action
|Triad Project Status
||Field Program Completed
|Reuse Objective Identified
||Commercial/Industrial – Military mission
Background Information About Site
- Site ST-123 is a petroleum, oils and lubricants (POL) fuel yard located 0.5 mile northeast of Hurlburt Field’s main entrance gate.
- The facility was constructed in the 1940s to store jet fuel, waste fuel, and waste oil.
- All above-ground storage tanks (ASTs) were removed prior to May 1994.
- Historical investigations conducted in the mid-1990s indicated site groundwater has been impacted by petroleum constituents and chlorinated volatile organic compounds (CVOCs).
- Hydrogen Release Compound (HRC®, Regenesis) was injected into the surficial aquifer between a depth of 15 and 65 feet below ground surface (bgs) in January 1999 (6,000 pounds), October 2000 (540 pounds), and August 2001 (4,118 pounds) in an attempt to destroy the CVOCs.
- 1,348 tons of petroleum-contaminated soil was excavated from the shallow zone in April 2001.
- 1,203 pounds of Oxygen Release Compound (ORC®, Regenesis) were injected into the groundwater beneath the excavated area in August 2001 to enhance degradation of petroleum constituents (benzene, toluene, ethylbenzene, and xylene [BTEX]).
- Although remediation of petroleum hydrocarbons was successful, CVOC contamination remained present and ill-defined.
Contaminant(s) of Concern
- Halogenated volatile organic compounds (VOCs)
Project Results and Outcomes
Field work was conducted from October 2004 through January 2005.
Prior to the Triad investigation, suspected source areas included:
- Building 90131 (Propulsion Building)
- Former underground storage tank (UST) Area
- Oil-water separator (OWS)
- Stormwater drainage off the flightline
- Sewer/utility lines
The Triad investigation identified the following probable source areas:
- Former UST Area
- Building 90141 (Aircraft Maintenance Building)/Former Building 90129 (Radio and Radar Shop)
Prior to the Triad investigation, lithography was poorly resolved:
- Multiple discontinuous peat, clay, and silt lenses/stringers were implied
- Large gaps were observed in initial model in silt/clay/clayey sand layers
- Lenses appeared to lie horizontal
Subsequent to the Triad investigation:
- The lithology was simplified to sand, semiconfining lenses, and Pensacola Clay
- Better delineation and correlation was obtained for transport and confining zones
- Variation in human description of soil samples was reduced and corrected
- Cone penetrometer (CPT) logs were based on assumptions about soil type using pore pressure data
- CPT logs and soil boring logs identified eight semiconfining layers (silt/clay/organic)
Prior to the Triad investigation, hydrogeology was understood as follows:
- Shallow groundwater zone (less than 15 feet bgs - water table wells)
- Upper intermediate groundwater zone (40-50 feet bgs)
- Lower intermediate groundwater zone (50-60 feet bgs)
- Deep groundwater zone (90-100 feet bgs)
Revised contaminant zones based on high-resolution membrane interface probe (MIP) response and lithologic layer data from the Triad investigation were as follows:
- Shallow groundwater zone (10-45 feet bgs)
- Intermediate groundwater zone (45-75 feet bgs)
- Deep groundwater zone (75-105 feet bgs)
- Main producing zone (105-150 feet bgs)
The project team and stakeholders agreed that the Triad investigation adequately completed the CSM and collected sufficient high-resolution data to allow attainment of the project objectives. A risk assessment and a Statement of Basis that evaluate the exit strategy and other alternative courses of action for the site were in preparation at the time this Triad Profile was originally prepared.
2. Project Information
The primary objectives of this Triad field investigation were to:
- Eliminate significant uncertainties in the CSM that hinder evaluation and selection of a full-scale corrective measure at Site ST-123
- Eliminate uncertainties in the CSM to ensure that all source areas are adequately delineated
- Collect sufficient, high-resolution data to effectively evaluate alternatives for a full-scale corrective measure
- Identify an exit strategy and a long-term approach to site management
Site Investigation (Includes RI/FS or Similar Detailed Investigation Work)
Triad Project Benefits
The focus on and prioritization of decision uncertainty led to an understanding of the contamination that would allow the exit strategy to be immediately pursued. This accomplished in roughly 10 months what approximately 10 years of prior work had sought to do.
The focus on the exit strategy for ST-123 required that an integrated, installation-wide exit strategy be considered.
Cost and Time Savings
No cost savings evaluation was developed. However, the compressed time frame of the Triad investigation (see the "Triad Project Benefits" section) would be expected to produce significant cost savings relative to a multiphase investigation process.
3. Triad Approach Information
Systematic Project Planning
A 3-day, facilitated SPP session was conducted. The primary contractor to the USAF presented the CSM. Session discussions initially centered on reaching consensus on an optimum exit strategy (i.e., meet MCLs) and potential contingencies to the optimum strategy. Hydrostratigraphic and contaminant uncertainty was defined in light of the exit strategy and potential remedial technologies that might be applied to the problem (including monitored natural attenuation [MNA]). A dynamic decision logic was developed that would systematically address the highest priority uncertainties using the most appropriate technologies.
An important element of the SPP sessions was that technical leadership passed from the Triad facilitator/expert to the USAF Project Manager (PM) to the lead contractor (CH2M HILL) over the course of the sessions. It was recognized by all that the contractor had to take ownership of the concepts by the end of the sessions in order to incorporate the key elements into the DWS work plan and execute them in the field.
Constant communication was maintained between stakeholders and team members. Time was taken for social interaction and discussion to build social capital.
Project Team Description
- AFSOC Project Manager (PM)
- Florida Department of Environmental Protection (FDEP) PM
- U.S. Environmental Protection Agency (EPA) PM
- AFSOC Restoration Project Manager (RPM)
- CH2M HILL PM
- CH2M HILL Field Team Leader (FTL)
- CH2M HILL Technical Expert
- Argonne National Laboratory Triad Facilitator
- Additional technical and contracting support from the Air Force Center for Environmental Excellence (AFCEE)
Dynamic Work Strategies
A robust decision logic was developed as a result of SPP and development of the DWS work plan. A graded approach was taken to defining and addressing decision uncertainty. Data needed to inform major decisions (i.e., likelihood of achieving MCLs vs. need for source treatment and land use controls) were collected early. Contingencies for limitations on field technologies were built into the decision logic.
An example decision logic flow chart can be found here.
Real-Time Measurement Technologies
High-resolution source area evaluation
- Membrane interface probe (MIP) logging: 51 locations completed between depths of 19 and 96 feet bgs for a total of 3,110 feet.
- Direct push technology (DPT) soil and groundwater sampling: 32 soil samples and 49 groundwater samples. An off-site analytical laboratory was used because of proximity and availability of quick turnaround results.
- Cone Penetrometer Testing (CPT): a total of 618 feet; 9 locations completed between depths of 19 to 78 feet bgs; and 15 pore pressure dissipation tests
- Sonic soil cores: 450 cores
- Soil geotechnical analysis: 6 samples
- Water Level Stormwater Analysis
Dissolved plume delineation and monitoring well installation
- Six multichamber wells completed to 150 feet bgs using sonic drilling, each with seven-screened chambers for a total of 900 feet
- Seven conventional monitoring wells completed (one shallow zone well, three lower intermediate zone wells, and three deep wells) for a total of 510 feet
Monitoring well groundwater sampling CVOC analysis: 75 laboratory samples and 93 samples by Color-Tec® test kits in the field
Geotechnical soil samples: 4 samples
Water level measurements
Technology Category(s) for Sampling and Analysis
- Direct-Push Geotechnical Sensors
- Direct-Push Groundwater Samplers
- Direct-Push Soil and Soil-Gas Samplers
- Test Kits
Specific Technology(s)/Model Used (e.g., SCAPs)
- Colorimetric Analysis – Color-Tec®
- DPT groundwater samples were collected by advancing the drive rods to depth and using either the Waterloo Profiler or Screen Point Sampling device. Groundwater samples were pumped through the sampling devices using a peristaltic pump and Teflon® tubing.
- MIP with electron capture detector (ECD), Geoprobe
Attached Technology Quick Reference Sheet (TQRS) Form
TQRS not prepared
Data Quality Assessment
Four categories of data were collected as part of this field effort, with each category having a different level of support Quality Assurance/Quality Control (QA/QC) documentation. The four categories, or levels, correspond to QC Levels I, II, III, and IV. Level I includes field monitoring activities such as measurements of pH, temperature, conductivity, dissolved oxygen, oxidation-reduction potential, and turbidity. Level II includes field screening activities, which are indicative of the nature of contamination (such as Color-Tec® and MIP), whereas Level III analyses provide laboratory "confirmation" (that is, collaborative data that manage analytical uncertainty from the field screening methods). Level IV laboratory analyses include the highest level of QC with significant documentation, equivalent to EPA Contract Laboratory Program analytical methods.
Data quality indicators of precision, accuracy, representativeness, comparability, and completeness (PARCC) were assessed by the following data QC parameters for Level III/IV confirmation data: daily calibration checks, method blanks, trip and purge blanks, surrogate spikes, matrix spikes, and matrix spike duplicates (MS/MSD).
Color-Tec® test kit quality control included the analysis of equipment rinsate blanks, analytical blanks, and field duplicates. Lot numbers of gas detector tubes were also recorded with analytical notes. No calibration using target compounds was used for the Color-Tec® test kit analysis because the presence of CVOC standards onsite and in the office required special storage and handling. A “correction factor” was developed by comparing Color-Tec® test kit results to laboratory results from selected samples. The correction factor was then applied to all samples to provide a field-determined concentration. Laboratory samples were selected to encompass the range of concentrations detected by Color-Tec® test kits and the MIP.
Data Management Approach and Tools
General data management protocols
Data management and communication activities incorporated:
- Spatial data collected using global positioning system (GPS) and traditional surveying technique.
- Geographical information system (GIS) mapping using ArcView.
- 3-D visualization performed using Environmental Visualization System (EVS)
Data Communication was managed through 1) conference calls and meetings; 2) daily field meetings; 3) email; and 4) use of a ftp site for posting data sets, maps, and documents.
No Further Action (NFA) Feasibility Screening Spreadsheets
As additional data were collected, the decision logic specified that the refined CSM would be used to evaluate whether NFA was feasible at the site. This was managed using a screening process, provided in a Microsoft® Excel® worksheet [see Slide 23 of the presentation "Triad Initiative: Tools for Defining Site Requirements"]. The NFA Feasibility Screening Matrix is intended to assist project stakeholders in deciding whether to proceed with a NFA site remediation strategy for a particular source area. This tool was basically designed to form the basis for the decision of whether to go with an aggressive remediation approach, or some less aggressive approach such as containment and partial mass removal. The process prescribed in this tool is relatively new and is meant to be updated, as necessary, to remain current with technological advances in remediation. This tool uses a weight-of-evidence approach to "score" source areas (and project conditions), realizing there are uncertainties in the problem. All project team members have input into the scoring process. The results from this scoring process were used to determine whether or not aggressive remediation options should be considered for Site ST-123. This screening tool was used to accomplish the following objectives:
- Compile most of the primary technical and non-technical factors that contribute to the decision process
- Present the factors in such a way that the team can screen them and prioritize (score) them individually
- Provide a common format such that all team members can come to a common understanding and reach an agreement.
4. Supporting Information
Key Triad Project Milestones
- June 2004: Systematic Planning Session
- September 2004: Fully reviewed Dynamic Work Plan
- October 2004: Field work commenced
- January 2005: Field work terminated
Dates of Operation - Field Work
Field work was conducted from October 2004 through January 2005.
Source(s) of Information
- Adaptations to Triad for Exit Strategy Development. Poster presented by Kim-Lee Yarberry; Chris Hood, P.E.; and Tom Palaia, P.E. (CH2M HILL).
- CH2M Hill. Decision Logic Flowchart for Site ST-123 Hurlburt Field.
- Chris Hood, CH2M Hill. 2006. Triad Initiative: Tools for Defining Site Requirements, Presentation to Land Revitalization Summit. October 30.
- David S. Miller, Argonne National Laboratory. 2005. Best Practices Used in the Triad Approach to Characterize TCE in Ground Water at Hurlburt Field, FL. Presentation to Technical Support Project Meeting, San Antonio, TX. October 25.
- Triad: The Fast Track to Reducing Conceptual Site Model Uncertainty. Poster presented by Kim-Lee Yarberry; Chris Hood, P.E.; and Tom Palaia, P.E. (CH2M HILL) and Artur Kolodziejski (AFSOC, Hurlburt Field).
Electronic Documentation of Supporting/Related Information
Point(s) of Contact
U.S. Air Force Special Operations Command (AFSOC)
427 Cody Avenue, HQ AFSOC/CEVR, Building 90033
Hurlburt Field, Florida 32544-5244
Restoration Project Manager
427 Cody Avenue, Building 90033
Hurlburt Field, Florida 32544-5244
David S. Miller
Argonne National Laboratory, Environmental Assessment Division
9700 S. Cass Ave, Building 900
Argonne, Illinois 60439
Last Update: 08/01/2006
To update this profile, contact Cheryl T. Johnson at Johnson.Cheryl@epa.gov or (703) 603-9045.