Gas N' Shop Facility

VEENA CORPORATION – GAS N’ SHOP FACILITY, POLLUTION COMPLAINT NO. 98-1068
Description of Role: Primary Environmental Consultant/Contractor
Key Personnel: Christopher Lalli and Andrew Alden
Project Cost: $581,320 to date
Time Period of Project Work: 1998 to present
Client: Veena Corporation
Client Representative: Mr. Abdul Malik
Regulatory Agency: Virginia Department of Environmental Quality (DEQ)
Regional Office(s): West Central

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. This example also demonstrates emergency response capabilities in terms of coordinating and providing services to abate hazardous conditions impacting receptors, both on, and immediately proximal to the release site. 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 December of 1997, the DEQ was notified of an apparent release related to the USTs located at Gas N Shop in Roanoke, Virginia. Gasoline vapors were detected on December 2, 1997 in the basement of the adjoining property located at 1214 Hamilton Terrace. Emergency crews were summoned and occupants were evacuated from the house until vapor levels decreased. The operator of the subject facility, Mr. Abdul Malik, commissioned tank tightness tests for each UST at the site. On December 7, 1997, all three existing USTs passed the portion of the tank tightness testing procedure designed to indicate leakage at or below the product level in the tanks. However, the ullage portion of the tank tightness tests, designed to test tank tightness above the level of product in the tanks, were not completed due to malfunctioning equipment on the part of the testing contractor. The product distribution line for one tank passed the test; however, tightness testing of the product lines associated with the other two tanks could not be completed due to apparent problems with the subject lines.
Veena Corporation, the owner, retained EEI’s services in May of 1998 to perform release investigation activities at the referenced site. Site check and initial abatement measure (IAM) activities were commenced by EEI in May of 1998 and completed in August of the same year. The release investigation included: 1) regulatory records review to investigate the petroleum release history of the site; 2) residual-phase investigation, that included the advancement of six soil borings on-site; 3) conversion of three soil borings to groundwater monitoring wells for assessment of separate- and dissolved-phase petroleum; 4) ambient air monitoring in the basement of the impacted residence, and 5) limited risk assessment activities. The results of this investigation determined that a significant petroleum release was reported in 1991, and was addressed under a previous pollution complaint (PC-91-1588). Elevated concentrations of residual- and dissolved-phase petroleum were documented in the northwestern portion of the site, in proximity to the UST tank pit. Groundwater flow across the site was found to be tending toward the west-northwest. Additionally, petroleum impacts in the subsurface of the site were contributing to the formation of vapor-phase petroleum, although detectable concentrations of vapor-phase petroleum were not present at the time of sampling in the basement of the residential dwelling. Identified potential receptors at risk from the migration of vapor- and dissolved-phase petroleum included nearby residences, an electric utility power station, and the Roanoke River. Based on the results of this investigation, additional activities were requested to further characterize the site.
The review of the Site Check/IAM report by the DEQ resulted in a request for an addendum. Most of the activities conducted under the IAM phase were repeated under this investigation; however, different activities to note include: 1) performance of a soil vapor gas survey to evaluate potential conduits for vapor-phase petroleum and; 2) vapor monitoring of stormwater drop inlets and subsurface utility vaults. The results of this investigation ascertained that the highest soil vapor concentrations were on the western portion of the site, and there was no direct correlation between utility corridors and vapor-phase petroleum migration. Geologic, hydrologic, and dissolved-phase concentration data suggested that two hydrostratigraphic units were present at the site. Dissolved-and vapor-phase data indicated that residual-phase was likely the primary source of subsurface vapor formation. Based on this information, EEI recommended that soil vapor extraction be implemented to remove residual- and vapor-phase petroleum.
Upon review of the IAM Addendum report, DEQ requested additional site characterization activities to further determine the amount and extent of petroleum hydrocarbons in the underlying groundwater, evaluate risk to impacted and/or potential receptors, and to assess applicable remedial technologies for site cleanup. The additional SCR activities included: the installation of supplemental wells in the western portion of the site; performance of waste load allocation calculations to determine whether or not the Roanoke River was at risk from the migration of dissolved-phase in the main component of groundwater flow, and performance of a DPE pilot test. Elevated concentrations of residual- and dissolved-phase were present in the newly installed wells, and dissolved-phase appeared to be migrating off-site towards the Roanoke River. Waste load calculations indicated that dissolved-phase was not a threat to the Roanoke River. The week long pilot test was successful at removing over 2000 lbs. of petroleum contamination from the subsurface of the site and; 5) DPE application appeared to lead to the migration and detection of separate-phase in one well on-site. Based on the detection of separate-phase and previous vapor-phase impact to a defined receptor, a Corrective Action Plan (CAP) was recommended to develop remedial strategies to address all phases of petroleum impacted in the subsurface of the site. A PSCR monitoring program was also recommended to track and manually remove (absorbent socks and hand bailing) separate-phase petroleum from the impacted well(s) on-site.
In February 2001, EEI completed a CAP that CAP identified the AEP Power Station, nearby residences, and the Roanoke River to be at potential risk from the off-site migration of separate, dissolved, residual, and vapor-phase petroleum. Based on these potential risks, the CAP recommended the implementation of DPE technology to simultaneously address all phases of petroleum contamination; however, remedial endpoints were not assigned for dissolved, residual, and vapor-phase petroleum.
On the afternoon of April 2, 2001, residents at 1214 Hamilton Terrace contacted the DEQ regarding the presence of gasoline vapors in the basement and living quarters of their home. Subsequently, per DEQ request, EEI responded to the emergency situation and conducted vapor monitoring to assess the levels of gasoline vapors present at the subject residence. Vapor concentrations were relatively low at all measured points; however, EEI recommended the implementation of an active ventilation system to encourage air turnover in the basement structure. Upon receiving verbal approval from the DEQ, EEI installed two ventilation blowers and associated exhaust systems to create negative pressure for continual airflow through the referenced structure. The subject blowers were recommended for continuous operation until vapor-phase petroleum was no longer perceived as a threat to the impacted residence.
On the afternoon of April 3, 2001, EEI staff met with Mr. Robert Howard of the DEQ to discuss remedial options for the subject site. EEI requested interim authorization for the immediate implementation of a mobile dual-phase extraction and treatment system (DPE) at the site. It was discussed that aggressive recovery of free, dissolved, and residual-phase petroleum was necessary to reduce the continual formation of vapor-phase petroleum. On April 5, 2001, DPE technology was implemented at the subject site to aggressively address petroleum contamination on-site. Per DEQ request, the subject system was shutdown on May 29, 2001 because vapor-phase emissions from the DPE exhaust stack appeared to be migrating and impacting receptors living in close proximity to the site. On June 5, 2001, EEI installed an activated carbon canister to temporarily treat emissions exiting the DPE exhaust stack. After approximately 24 hours of system operation, air emissions exiting the subject treatment vessel were measured at approximately 3000 parts per million (ppm), indicating the treatment capacity of the activated carbon had been significantly reduced. Based on this information, system operation was halted on June 6, 2001 until a more effective and permanent air emission; treatment technology could be implemented to treat emissions emanating from the DPE exhaust stack. Approximately 1,600 lbs. of petroleum impact were removed with the DPE system under Interim Authorization. PSCR monitoring activities were also halted after the implementation of interim authorization and the total amount of separate-phase removed during this program was approximately 12 gallons.
A CAP Addendum was requested to prescribe a site remedial endpoint for vapor-phase petroleum and to address off-gas treatment technology for DPE exhaust stack emissions. It is important to note that two additional wells were also installed in a narrow grass strip between the site and impacted residential house during this phase. This involved exposing a high voltage power line to ascertain whether or not the noted sentinel wells could be safely installed. A vapor-phase petroleum endpoint was set for several wells on-site that contained elevated concentrations of petroleum. The vapor-phase endpoint was prescribed by measuring ambient vapor concentrations in two wells on-site that had not indicated impact from any petroleum phase during activities associated with the current pollution complaint. This determination strategy was utilized to rule out background soil concentrations not attributable to petroleum impact (organic matter decay, etc.). The specifications for a thermal/catalytic oxidation system applicable to DPE emissions treatment were also investigated and recommended under this phase.
The following activities were completed prior to the re-implementation of active remediation on-site: 1) permit acquisition to discharge treated effluent to the City of Roanoke sanitary sewer system; 2) purchase of the DPE and thermal/catalytic oxidation systems through formal bidding procedures; 3) directional drilling for the installation a high-pressure gas line to the site for operation of the oxidation system; 4) installation of a security system to safeguard remediation operations and; 5) subsurface trenching and line installations to designated wells to enable traffic access across the site during active remediation. DPE and the off-gas treatment unit were implemented on-site in September 2002 and active remediation operations to address petroleum impact have generally been on-going to date. The DPE and oxidation systems are equipped with an automated telemetry system, which enables remote operation and monitoring of the failsafe engineering alarms. To date, the DPE system has removed approximately 6.5 tons of subsurface petroleum impact and separate- and vapor-phase endpoints have been maintained on-site for the past two calendar months (December 2003 and January 2004). Additionally, elevated concentrations of vapor-phase petroleum have not been detected in the impacted residence since implementation of active remediation under interim authorization. Due to this progress, the site may enter into a Post-CAP monitoring program within the next couple of months.

Staff and Resource Involvement:

Mr. Alden and Mr. Swan provided principal oversight and project management assistance throughout the term of this project. Mr. Lalli has been responsible for project management since 1999, which included logistics and strategies for all phases including and occurring after PSCR monitoring. 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. Mr. Speiden was responsible for the on-site coordination of the subsurface extraction line installations. Mr. Sexton and Mr. Lare were responsible for the operation of the drilling equipment utilized to install the two sentinel wells. Mr. Tollefson and Mr. Sexton were responsible for all on-site activities relating to the implementation of the DPE and thermal oxidation systems on-site. Pertinent equipment owned and operated by EEI during this project included: 1) ventilation blowers and associated exhaust systems; 2) Caterpillar 416B backhoe/front-end loader; 3) Freightliner 8CY dump truck; 4) Oil-sealed DPE and associated treatment system (oil/water separator, air stripper, and air sparging system); 5) hollow-stem auger drill rig; and; 6) thermal/catalytic oxidation system. Monitoring well installation via air rotary was subcontracted to various drilling companies, however EEI provided field management of all monitoring well installations. Directional drilling services were also subcontracted with oversight provided by the EEI project manager.

 

.