Soil Vapor Extraction and Groundwater Containment at OU1, Shaw AFB, South Carolina

Site Name:

Shaw Air Force Base

Location:

South Carolina

Period of
Operation:

POL SVE system - December 1995
- ongoing (as of April 1998)
Interim Response Area A - February 1992 - November 1996
Interim Response Area C - April 1995 - September 1997

Cleanup
Type:

Full-scale cleanup

Vendor:

IT Corporation

Technology:
POL Yard
- Soil Vapor Extraction (SVE) - vacuum extraction wells, blowers, an oil/water separator, and thermal/catalytic oxidation units.

Interim Groundwater Containment System - Area A
- Fuel recovery and a groundwater treatment system. Recovery wells, iron pretreatment, entrained oil removal, solids removal, packed air stripper. System upgraded in May 1997 with dual-phase recovery pumps, oil/water separator, equalization tank, and shallow-tray air stripper units.

Interim Groundwater Containment System - Area C
- Passive free product recovery using one recovery well

Cleanup Authority:
Installation Restoration Program

Regulatory Point of Contact:
Information not provided
Additional Point of Contact:
U.S. Air Force Air Combat Command

Contaminants:
BTEX, Petroleum Hydrocarbons, Free Product (JP-4 fuel)

- 400,000 gallons of JP-4 in the groundwater; the size of the dissolved phase plume was approximately 47 acres.

Waste Source:
Fuel Spill

Type/Quantity of Media Treated:
Soil
- 30,000 square feet (areal extent); sands and silts; confining clay layer at 70 to 80 feet below ground surface (bgs)

Groundwater
- 47 acre plume (dissolved JP-4 fuel)

Purpose/Significance of Application:
SVE system to remediate soil and two interim response action systems to contain groundwater

Regulatory Requirements/Cleanup Goals:
- The operational objective of the SVE system was to remove contamination from the soil as cost-effectively as possible to prevent contamination of surrounding soil and groundwater.
- The operational objectives of the Interim Response for Area A was to contain the plume by removing free product as quickly and cost-effectively as possible to prevent continued contamination of surrounding soil and groundwater; the objective of dissolved phase containment was to operate efficiently over a relatively long period of time.
- The operational objective of the Interim Response for Area C, free product source removal, was to remove liquid-phase contamination as quickly and cost-effectively as possible to prevent continued contamination of surrounding soil and groundwater.

Results:
- SVE at POL Yard - Total contaminant removed through 19 months of operation (July 1997) was 518,000 lbs of JP-4 fuel, with removal rates ranging from 2,560 to 94,800 lbs/month. The system is still operating.
- Groundwater Containment Area A - Data on whether containment was achieved is not available. Total contaminant removed after 4 years of operation (through January 1996) was 114,340 gallons of JP-4 free product (monthly removal rates ranged from 0 to 9,980 gallons) and 171 gallons of dissolved phase JP-4 (monthly removal rates ranged from 0 to 10.7 gallons).
- Groundwater Containment Area C - Total contaminant removal after 1.4 years (through August 1996) was 12,766 gallons of JP-4 free product (monthly removal rates ranged from 266 to 2,145 gallons).

Cost Factors:
The report includes detailed data on O&M costs versus amount of contaminant removed and the effects of system modifications on these costs.

- SVE system at POL Yard - Total O&M costs after 19 months of operation was $568,500 (monthly ranged from $18,000 to $57,500). The average O&M cost per unit of contaminant removed was $1.09/lb
- Groundwater Containment Area A - Total O&M costs after 4 years of operation was $995,500 (monthly ranged from $674 to $90,100). The average O&M cost per unit of contaminant removed was $8.69/gallon of JP-4. Groundwater Containment Area C - Total O&M cost was $33,000 (monthly ranged from $437 to $6,187). The average O&M cost per unit of contaminant removed was $2.59/gallon of JP-4.

Description:
OU1 at Shaw AFB, located in South Carolina, includes four IRP sites. This report focuses on the OU1 POL yard SVE system, the OU1 Area A Interim Response groundwater containment/treatment system, and the Interim Response Area C groundwater containment system (free product recovery). Contamination at OU1 included JP-4 fuel and BTEX, with an estimated 400,000 gallons of free product present in the groundwater.

The SVE system at the POL yard included 30 vacuum extraction wells, four vacuum monitoring wells, three SVE vacuum blowers, an oil/water separator, and two thermal/catalytic oxidation (CatOx) units. (Thermal oxidation was used until December 1997; replaced by CatOx). In December 1996, five VEP wells from OU1 Area B were connected to the system. The system was operated under 18 in of Hg and data are provided through July 1997. The Interim Groundwater Containment System at Area A included nine recovery wells, iron pretreatment, entrained oil removal, solids removal, packed air stripper. Treated effluent was discharged to a sewer and data are provided through November 1996. The Interim Groundwater Containment System at Area C included one recovery well for free product recovery and data are provided through August 1996. In September 1997, the Area C system was modified to a full-scale system.