Blevins Grocery Store

BLEVINS GROCERY, VA PC#00-1031
Description of Role: Primary Environmental Consultant/Contractor
Project Team Leader(s): Andrew Alden, Jeffrey A. Fisher, Jr.
Project Cost: $129,500 to date
Time Period of Project Work: October 1999 to Present
Client: Blevins Grocery
Client Representative: Ms. Rita Blevins
Regulatory Agency: Virginia Department of Environmental Quality (DEQ)
Regional Office(s): South West

Introduction:

Environmental Engineering, Inc. (EEI) is presenting this project as an example of EEI’s ability to identify, characterize, and provide corrective action at a rural petroleum release site located in karst geology, which presented complex and challenging subsurface characteristics.
 

Scope of Work:

This petroleum release was discovered in October of 1999 during UST removal at the Blevins Grocery in Adwulf, VA. EEI staff observed numerous perforations in several of the tanks, and approximately 37 tons of petroleum-contaminated soil was removed prior to backfilling. EEI’s IAM report recommended a thorough receptor survey, and that a fracture trace analysis was appropriate due to the presence of karst geology.
During the SCR, a receptor survey of the area within a 0.25-mile radius of the subject facility identified several private supply wells, springs, and surface streams that may be potentially impacted by off-site migration of petroleum contaminants. A fracture trace analysis was used to determine the locations of three monitoring wells. These wells were installed using an air-rotary drilling rig because bedrock was encountered within three feet of the ground surface. After installation, one of these wells was found to contain free product. Because of the karst conditions, free product, and several potential receptors, an SCRA was recommended, which would include the installation of additional monitoring wells in fractures, which were to be identified by an electrical resistivity survey.
The September 2000 SCRA was prepared by EEI, and included the results of an electromagnetic terrain conductivity investigation. This investigation successfully identified several large fractures in the complex subsurface conditions controlling groundwater and contaminant flow. Three additional monitoring wells were installed, two of which intercepted one large fracture, and these were found to contain free product accumulation.
A CAP was developed by EEI in March of 2002 that proposed remedial endpoints for both separate- and dissolved-phase contamination, and the application of high vacuum extraction via a liquid ring pump system. This plan was developed based on previous experience at similar sites and the operation of a DPE pilot study in preparation for the CAP. This CAP included historical groundwater elevation data that showed considerable seasonal fluctuations in on-site water table elevations from approximately 45 to 80 feet below grade.
Following several discussions with the DEQ case coordinator, it was agreed that a CAP Addendum was required that would include the installation of a downgradient and off-site sentry well, and the performance of a second DPE pilot study to determine what effect the highly fluctuating groundwater table had on contaminant removal rates. The pilot study was managed by Mr. Fisher, and was conducted when the water table was significantly higher than during the previous study. The pilot study provided data suggested that the management of water table elevations at certain distances below grade, and within one of the large fractures or voids, significantly enhanced the contaminant mass recovery rates. These data were used to alter the remedial recommendation from a high vacuum system to a total fluids recovery system, which was proposed for accurately maintaining groundwater elevations. This system is currently being investigated using a total fluids pump test on one of the monitoring wells containing free product.
 

Staff and Resource Involvement:

Mr. Alden has provided engineering oversight and project management assistance throughout this project. Mr. Lalli was responsible for field management of monitoring well installation, operation of the first pilot study, and scheduling of resources. Mr. Fisher has been responsible for project management since 2002, which included drafting the CAP and CAPA, field management of the sentry well installation, and management of the second DPE pilot study. Equipment owned and operated by EEI that was used on this project included a Caterpillar 416B backhoe, a Freightliner 8CY dump truck, and two mobile liquid ring pump DPE systems. Monitoring well installation via air rotary was subcontracted to various drilling companies; however, EEI provided field management of all monitoring well installations.