Print this profileClose this window

Real-time Delineation of a Free Product Fuel and Groundwater Contamination using a Membrane Interface Probe at the Fannon Oil Site, Alexandria, Virginia

Triad Elements Used

Triad logo

Table of Contents

  1. Site Information
  2. Project Information
  3. Triad Approach Information
  4. Supporting Information



The Virginia Department of Environmental Quality (VADEQ) was involved with the Former Fannon Petroleum Services Site (Site) since the early 1980s. A Triad Approach-based HRSC was implemented in the early 2000s to better define the nature and extent of contamination and to gain concurrence and acceptance from the stakeholders on the characterization and remediation strategy. Site-specific environmental cleanup-related needs included:

Historical sampling and monitoring data provided a preliminary delineation of the contamination. Systematic project planning (SPP) was used to develop a Triad-based strategy to define the area of contamination in the context of redevelopment. A direct-sensing real-time measurement technology was used to conduct additional HRSC wherein contamination pathways were defined and an additional contaminant plume lobe was discovered. The use of a DWS allowed for adaptive environmental measurement to efficiently and effectively characterize the contaminated area in a single mobilization.

In order to remove the contaminant sources, the underground storage tanks (UST), above ground storage tanks (AST), and all buildings on the Site were removed; the extraction wells on the Site were abandone; and the contaminated soil was excavated. The existing treatment facility which included both groundwater pump-and-treat (P&T) and soil vapor extraction (SVE) elements on the Site was moved to an adjacent property and reconnected to the extraction wells on that property. The P&T system included an oil/water separator, air stripper, two carbon units, and one bag filter. The SVE system included one blower and two air-phase carbon units. The adjacent property is owned by a separate property owner, that operates the Shiloh Baptist Church, which provides childcare services. The treatment facility was relocated as a function of stakeholder and community engagement efforts; based upon stakeholder input, the adjacent property owner agreed to have the systems moved to their property. The remedial system currently is in operation at this location.

1. Site Information

Site Name Former Fannon Petroleum Services
Location Alexandria, VA
Site Type  Gasoline Service Station/Petroleum Storage Facility
Project Lead Type  PRP Lead
Regulatory Lead Program  Voluntary Cleanup Program
Reuse Objective Identified  Yes
Proposed Reuse:  Residential

Background Information About Site 

The Site was used as a fuel depot since the late 1800s. A bulk storage terminal was built in 1962 and received fuel supplies by a rail line that passed through the property. Fuel was stored in USTs and ASTs with a combined capacity greater than 500,000 gallons.

The first pollution complaint against the Site was registered with the Virginia State Water Control Board in April 1982 when a city work crew believed they had struck an underground oil line. At that time, 15 to 18 million gallons of fuel were being sold at the Site per year.

To assess contamination concerns, monitoring wells were constructed on the Site, one of which showed as much as 40 inches in apparent thickness of petroleum product. Recovery wells were then constructed over the entire Site, which were initially capturing 6.0 gallons per hour. By 1985, over 27,000 gallons of product had been recovered.

In the early 2000s, a new VADEQ project manager was assigned to the Site and recognized the benefits that using the Triad Approach would bring in furthering the remediation of the site. With the development of the post-cleanup plan, which involved redevelopment of the Site into residential town homes and condominiums, Brownfields redevelopment became the driver for site cleanup. The post-cleanup plan involved redevelopment of the site into residential town homes and condominiums.

The Triad Approach was used to:

The Triad Approach was also critical in obtaining agreement between all stakeholders involved with the Site.

Contaminant(s) of Concern 

Contaminated Media 

Project Results and Outcomes 

The use of real-time measurements and a DWS allowed for the characterization of the Site in a single mobilization. HRSC results supported historical data but also identified a previously unknown lobe of the contaminant plume and led to the discovery that utility lines were serving as preferred pathways for contaminant migration.

A groundwater P&T and a SVE system operated on the Site from 2001 until 2007. In March 2007, the systems were relocated to a property adjacent to the Site which was owned by a non-responsible party and on which the Shiloh Baptist Church provides childcare services. The systems were reactivated in their new location in September 2007.

To date, the P&T system has treated over 5.6 million gallons of petroleum contaminated groundwater and removed over 4,200 pounds (lbs) of total petroleum hydrocarbons - diesel range organics (TPH-DRO) contaminants, over 350 lbs of fuel contaminants in the form of benzene, toluene, ethylbenzene, and xylenes (BTEX), over 78 lbs of methyl tert-butyl ether (MTBE), and 15 lbs of naphthalene. Approximately 5,000 gallons of fuel oil are believed to have been recovered during that time. In addition, almost 7,000 lbs of subsurface petroleum vapors have been removed.

The P&T and SVE systems remain in operation as of September 2010. Sampling results indicate that the P&T system is providing hydraulic control of the contaminant plume while remediating remaining free-phase fuel oil and dissolved-phase groundwater contaminants. The P&T system is in place in order to achieve the removal of free-phase fuel oil from the water table to a thickness of less than 0.01 foot and is anticipated to continue in operation towards this goal. The goal of the SVE system is to achieve <0.01 ppm of vapor-phase contaminant concentrations. A trial shut-down of the system is anticipated based on decreasing SVE concentrations.

2. Project Information

Remedial Phases

Triad Project Benefits 

For almost 20 years, contamination at the Site had been addressed by the responsible party through the use of recovery wells. SPP was used to bring together all stakeholders to reach consensus on the approach to site characterization and remediation. DWS were used during the HRSC to adapt to the data that was generated using direct-sensing real-time measurement technologies. While exact cost and time benefits have not been quantified, it is believed that site remediation would have been completed in less time and at a lesser cost had the site characterization technologies been available when the contamination was initially discovered, and if all stakeholders were involved sooner.

3. Triad Approach Information

Systematic Project Planning 

The VADEQ project manager used SPP, a Triad best management practice (BMP), to engage all stakeholders and facilitate collaborative decision-making. The SPP process included the creation of a CSM. Using the CSM as a basis for project design, steps required to characterize the site and a method to complete the process were identified. In addition, a continuously-updated corrective action plan (CAP) was initiated. Stakeholders collectively decided to use:

  1. a MIP to characterize in high-resolution the distribution of volatile organic compound (VOCs) at the site;
  2. a DWS to adaptively identify specific direct-sensing locations; and
  3. real-time stakeholder decision-making to support the field effort.

Project Team Description 

The VADEQ project manager was the principal decision maker for the Site. Stakeholders with input to site decisions included the responsible party (Fannon Petroleum Services, Inc.), the City of Alexandria, and the Site redeveloper (Van Metre Homes). Other parties involved in the systematic project planning process included Shiloh Baptist Church, neighbors, and citizens. The site contractor for both Fannon Petroleum Services, Inc. and Van Metre Homes was Environmental Consultants and Contractors, Inc. (ECC).

Dynamic Work Strategies 

Prior to the use of the Triad Approach, treatment and monitoring samples were sent to an off-site laboratory for analysis. In a collaborative data approach, historical monitoring and recovery data were used to define the areas where a high-resolution MIP survey would be conducted. While a general plan was determined prior to conducting the survey, the DWS allowed the team to evaluate the data that were provided in real-time and determine if additional direct-sensing locations were required. Initial MIP data closely paralleled what was anticipated based on historical data. A previously unknown and unanticipated plume lobe was identified, however, and the MIP survey plan was modified to complete plume delineation.

The high-density data set generated from the MIP survey results was provided to project stakeholders in the form of three-dimensional (3-D) visualizations using vendor-provided imaging software. The 3-D visualization allowed all of the stakeholders to understand the extent and path of the contamination and reach consensus on a remediation strategy appropriate to address the risks posed by the contamination.

Real-Time Measurement Technologies 

The Triad Approach investigation leveraged historical site data to design the MIP survey. Because Site contamination was known to be in the range of MIP sensitivity and geologic conditions were conducive to direct-push technology, it was not necessary to perform a demonstration of methods applicability (DMA).

Technology Category(s) for Sampling and Analysis 

Specific Technology(s)/Model Used (e.g., SCAPs) 

Technology Vendor(s)

Attached Technology Quick Reference Sheet (TQRS) Form 

TQRS not prepared

Data Quality Assessment 

During the Triad Approach, the high-resolution MIP survey relied on historical data to gauge calibration levels. Though no samples were taken during the survey, subsequent groundwater samples were taken for confirmation of treatment system performance. These samples were analyzed by the following analytical methods:

Data Management Approach and Tools 

MIP data was effectively communicated to the stakeholders through the use of SmartDataŽ, a proprietary 3-D visualization technology and programming provided by Columbia Technologies, the MIP survey field services vendor.

4. Supporting Information

Key Triad Project Milestones 

Source(s) of Information

Electronic Documentation of Supporting/Related Information

PDF Implementation of Triad for Petroleum Brownfield's Cleanup and Reuse (42 MB)

Point(s) of Contact 

Randy Chapman
Virginia Department of Environmental Quality Remediation Division
13901 Crown Court
Woodbridge, Virginia  22193
Telephone icon 703-583-3816

Last Update:  11/13/2010

To update this profile, contact Cheryl T. Johnson at or (703) 603-9045.