T & T Petroleum Station

T&T PETROLEUM STATION NO. 2, POLLUTION COMPLAINT NO. 98-1006
Description of Role: Primary Environmental Consultant/Contractor
Key Personnel: Christopher Lalli, Andrew Alden, Christopher Swan, and Carl Cirillo
Project Cost: $672,221.38 to date
Time Period of Project Work: 1997 to present
Client: T&T Petroleum Company Inc.
Client Representative: Mr. John Thomas
Regulatory Agency: Virginia Department of Environmental Quality (DEQ)
Regional Office(s): West Central (1997 to 2002) and South Central (2002 to present)

Introduction:

Environmental Engineering, Inc. (EEI) is presenting this project as an example of our experience in providing/performing environmental consulting and contractual services under several of the release investigation and corrective action phases that are defined under the Virginia Petroleum Storage Tank Fund (VPSTF) program. The discussions presented in the following sections of this example demonstrate our technical experience and capabilities, pertinent to the proper identification, characterization, and remediation of petroleum-impacted media at a decommissioned service station in a rural section of south central Virginia. All professional/field services and equipment discussed in this example were solely provided by EEI, unless explicitly noted in the Scope-of-Work or Staff Resources and Involvement sections of this project overview.

Scope-of-Work:

In November 1991, T&T Petroleum Company, Inc. (T&T) contracted Marshall Construction Company to close five underground storage tank (UST) systems located at their Station No. 2 site in Ringgold, Virginia. Minor concentrations of petroleum were detected in three samples, collected from beneath some of the removed tanks. Additional release investigation activities were requested by the DEQ, and T&T Petroleum retained EEI’s services to complete those activities in July of 1997. Results of this investigation indicated soil-impacts above the release threshold value for total petroleum hydrocarbons, and a pollution complaint was issued for the site. Based on the findings of the residual-phase investigation and presence of potential receptors (creek and private drinking water wells), EEI recommended that groundwater quality be evaluated at this release site.
EEI completed an SCR investigation in March of 1998. Activities performed under this phase included: 1) receptor survey to identify potential receptors within a 0.25 mi. radius of the site; 2) installation of eight monitoring wells; 3) slug testing; 4) groundwater sampling for dissolved-phase gasoline constituents and; 5) one-dimensional contaminant fate and transport modeling to predict potential contaminant transport. The results of this investigation determined that several potential receptors were located within the defined radius, and that the subsurface of the site was heterogeneous in nature. Several monitoring wells, in addition to two supply wells, were impacted by detectable concentrations of dissolved-phase petroleum. Groundwater velocity was predicted at approximately 80 ft/yr., and the main component of groundwater flow appeared to tend towards the north-northeast. Impacts to nearby receptors was determined to be probable based on the contaminant transport modeling. Given these results, additional activities were requested to further characterize the site.
Further characterization included the completion of an SCRA investigation in October of 1998. Most of the activities conducted under the SCR phase were repeated under this investigation; however, different findings and/or activities to note include: 1) detection of separate-phase petroleum in previously and newly installed wells; 2) main component of groundwater flow appeared to tend towards the south; 3) lateral distribution of the separate-phase petroleum plume was not consistent with the primary groundwater flow direction; 4) coordination with VDOT and implementation of traffic control measures to install wells in the median of Virginia State Route 58 and; 5) installation of an automated, pneumatic free product recovery system to address separate-phase petroleum impacts. Based on the newly established groundwater flow direction and lateral distribution of the separate-phase plume, a geophysical analysis was requested to investigate the possibility of preferential/fracture flow.
The geophysical analysis (fracture trace analysis/outcrop mapping and electrical resistivity survey) was performed in another addendum (SCRA#2), which was completed in November of 1999. This investigation identified lineaments and joints in the bedrock surface that indicated preferential groundwater flow, and thus petroleum migration to the east. This conclusion was further evidenced by monitoring/sampling results that indicated the migration of separate- and dissolved-phase petroleum to the east across the northern portion of the site. Subsequently, this information was utilized to strategically install several monitoring wells for successful delineation of the dissolved- and separate-phase petroleum plumes in the secondary component of flow. A DPE pilot event and pump test were performed under this phase to evaluate remedial technologies in terms of achieving defined endpoints for this release site. The 60-hour DPE event was successful at removing 40-gallons of free product, 9,495-gallons of groundwater, and approximately 62 lbs. of TPH in the system exhaust and water effluent streams. The 48-hour pump test removed 1,948-gallons of groundwater and analytical results obtained from samples collected during water removal indicated an overall TPH mass removal of 0.13 lbs. Based on the extent of the petroleum release and proximity of sensitive receptors to the release site, a Corrective Action Plan (CAP) was recommended to develop remedial strategies to address risk-based endpoints for separate- and dissolved-phase petroleum.
In July of 2000, EEI completed a CAP that proposed remedial endpoints for separate- and dissolved-phase impact to safeguard receptors identified under the characterization phases. The remedial strategy in the CAP proposed the use of DPE, as this technology is capable of simultaneously addressing multiple phases of petroleum impact and proved to be effective in terms of petroleum mass removal during the small-scale pilot study. Upon approval of the CAP, DEQ requested separate-phase remediation under the initial phase of Corrective Action with the stipulation that a Corrective Action Plan Addendum (CAPA) be developed to address dissolved-phase impacts, once free product endpoints had been achieved on-site. The free product recovery system installed under the SCRA phase was recommended for continual operation until DPE technology could be implemented on-site.
The following activities were completed prior to implementation of DPE technology on-site: 1) VPDES permit acquisition to discharge treated effluent to an unnamed intermittent tributary of Golden Branch Creek; 2) subsurface trenching and line installations to enable extraction from designated wells and provide effluent conveyance to the intermittent tributary; 3) three-phase electrical power and landline telephone arrangements with Danville Electric and Verizon, respectively; 4) installation of a security fence to safeguard remediation operations and; 5) removal of the free product recovery system, which had successfully removed approximately 170-gallons of free product. DPE technology was implemented on-site in February of 2002, and active remediation operations to address separate-phase impact have generally been on-going to date. The DPE system is equipped with an automated telemetry system, which enables remote operation and monitoring of failsafe engineering alarms. To date, the DPE system has removed approximately 10 tons of subsurface petroleum impact and separate-phase endpoints are close to being met (thicknesses less than 0.1 ft.) at historically impacted wells on-site. The DPE systems have proven to be extremely effective, since several wells initially contained product thicknesses in excess of four (4) ft. prior to implementation of Corrective Action. Due to this progress, EEI recommended CAPA development to the DEQ in December of 2003.

Staff and Resource Involvement:

Mr. Alden and Mr. Swan provided principal oversight and project management assistance throughout the term of this project. The logistics and strategies for the geophysical analysis were developed and managed by Mr. Alden. Mr. Carl Cirillo was involved with project management activities during site characterization, which included well installation oversight and implementation of the interim free product recovery system. Mr. Lalli has been responsible for project management since 2002, which included logistics and strategies for the implementation and operation of active remediation on-site. Mr. Lalli has also been involved with field management services and scheduling of staff and associated resources. Mr. Tollefson was responsible for telemetry system installation and programming activities as well as providing services relating to equipment repair/maintenance. EEI field technicians collected all field data and provided support for the operation of equipment and machinery. Pertinent equipment owned and operated by EEI during this project included: 1) pneumatic free product recovery pumps and air compressor; 2) Caterpillar 416B backhoe/front-end loader; 3) Freightliner 8CY dump truck and; 4) Oil-sealed liquid ring pump DPE and associated treatment system (oil/water separator, air stripper, and air sparging system). Monitoring well installation via air rotary was subcontracted to various drilling companies; however, EEI provided field management of all monitoring well installations. An applicable environmental company provided rental equipment to EEI for the electrical resistivity survey.
 

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