In-Situ Soil Vapor Extraction
- Network of 22 extraction wells (varying combinations are used)
- 2 Horsepower SVE blower motor
- Knockout tank to separate vapor and liquid phases.
State and EPA
9711 (National Security)
U.S. Air Force
Restoration Program Manager
550 Tabosa Avenue
Holloman AFB, New Mexico 88330
|Regulatory Point of Contact:|
Santa Fe, New Mexico 87502
- BTEX and TPH
- Maximum concentrations - Benzene (48,000 µg/kg), Toluene (210,000 µg/kg), Xylene (500,000 µg/kg), Ethylbenzene (180,000 µg/kg) and TPH (17,500 mg/kg)
Chronic and acute surface releases of JP-4 jet fuel, AVGAS and diesel fuel from aboveground storage tanks
Type/Quantity of Media Treated:
- Estimated 9,500 cubic yards of soil (in-situ)
- Estimated 44,000 pounds of TPH removed from the soil
Purpose/Significance of Application:
Treatment system has operated successfully with minimal downtime or maintenance requirements
Regulatory Requirements/Cleanup Goals:
NMED has set the following soil cleanup criteria for POL sites at Holloman AFB:
- 1000 mg/kg TPH
- 25 mg/kg Benzene
- Removal of all floating free-phase hydrocarbons
Confirmatory soil samples collected in 1997 indicate that soil TPH concentrations have been reduced below the regulatory guideline of 1,000 mg/kg. Previous sampling has indicated that benzene concentrations are below 25 mg/kg. Floating free-phase hydrocarbons have never been observed in the subsurface at the site.
The total cost for this project (through August 1997) was $610,000. This translates to a cost of $64 per cubic yard of soil treated.
During the 1960s and 1970s, several releases of JP-4 jet fuel, AVGAS and diesel fuel occurred in a POL storage area at Holloman AFB. Releases included chronic leaks and a 30,000-gallon spill that occurred in 1978. The site previously contained 14 aboveground POL storage tanks. All 14 tanks were removed from the site in 1987.
The site of the releases was investigated as part of the IRP program and two sites (Sites 2 and 5) were identified in the vicinity of the POL storage area. Because the two sites were similar in nature and in close proximity to each other, they were ultimately combined into one site (Site 2/5). Subsequent investigations at Site 2/5 identified an area requiring soil remediation. This area was selected based on soil cleanup criteria developed for POL sites at Holloman AFB. This area is 80 feet wide by 200 feet long. Soil borings indicated that soil contamination extended 16 below the ground surface at the site. It was determined that groundwater remediation was not required based on the quality of the groundwater and the lack of floating free-phase hydrocarbons at the site.
In 1994 and 1995, an SVE system was constructed at the site. The system includes 22 extraction wells, a 2-horsepower blower and a knockout tank to separate vapor and liquid phases in the extraction stream. The system was started in April 1995 and is currently still in operation (as of October 1998). It is estimated that 44,000 pounds of TPH have been removed from the soil at the site. Since 1995, several different extraction well configurations have been used. For a period in 1997, all 22 wells were in use simultaneously.
On several occasions since system start up, soil borings have performed at the site to determine if cleanup goals have been met at the site. The most recent sampling event (October 1997) indicated that the goals had been met. In March 1998, a Final Characterization Study was submitted to NMED for review. This study recommended that no further remedial action be conducted at Site 2/5. Approval of this recommendation was pending at the time of this report.
In addition to meeting soil cleanup criteria at Site 2/5, the SVE system has consistently operated below limits set by NMED for allowable air emissions of organic compounds.