Fact Sheets Graphic

Travis Air Force Base Fact Sheets

This database holds fact sheets on Travis Air Force Base weapons, organizations, inventory, careers and equipment. Air Force fact sheets contain up to date information and statistics. If a fact sheet is not listed, please contact the 60th Air Mobility Wing Public Affairs office at 60amwpa@us.af.mil. 

Fact Sheets Graphic

Travis Air Force Base Fact Sheets

This database holds fact sheets on Travis Air Force Base weapons, organizations, inventory, careers and equipment. Air Force fact sheets contain up to date information and statistics. If a fact sheet is not listed, please contact the 60th Air Mobility Wing Public Affairs office at 60amwpa@us.af.mil. 

Popular

  

KC-10 Extender             C-17 Globemaster III                   C-5M Super Galaxy

 

 

Fact Sheet Search

Fact Sheet Alphabetical List

Fact Sheets

DP039 - Building 755




An In situ Bioreactor over Former Sump

Building 755 (DP039) was the base Battery and Electric Shop, where a former acid neutralization sump for the disposal of battery acid had also received chlorinated solvents. The sump was removed in 1993, but a plume of solvent-contaminated groundwater remains. Trichloroethene (TCE), a chlorinated solvent, was found in high concentrations in the groundwater beneath the footprint of the former sump. Lead residue from the lead-acid batteries was found around the edges of the former sump area. Building 755 was torn down in 2009.

Based on human health and ecological assessments of the potential risks posed by the contaminants, the West/Annexes/Basewide Operable Unit Groundwater Interim Record of Decision selected a combination of Dual-Phase Extraction, Extraction and Treatment, and Monitored Natural Attenuation for the groundwater, and the West/Annexes/Basewide Operable Unit Soil Record of Decision selected Land Use Controls for the soil at this site.

The base constructed a dual-phase extraction (DPE) system in 2001 to clean up the source of the groundwater contamination. This system ran from 2001 to 2008. During this operating period, contaminant concentrations declined and TCE removal rates dropped, resulting in cost inefficiencies. Therefore, in November 2008, DPE was discontinued and a bioreactor was installed.

An in situ bioreactor is a simple and cost-effective application of enhanced reductive dechlorination technology that can be used to accelerate the removal of chlorinated volatile organic compounds (CVOCs) from both soil and groundwater in a known source area. Bioreactors consist of the following three components:
· An excavation of contaminated soils in a known source area. The excavation extends as close to the water table as feasible. Some disposal of soils is usually required.
· Backfill of the excavation with a bioreactor mixture of organic mulch and gravel to promote the long-term generation of organic carbon and allow a permeable and well-mixed environment for enhancing reductive dechlorination.
· An extraction well is installed to recirculate groundwater through the bioreactor and source area aquifer. This recirculation distributes organic substrate below or downgradient of the bioreactor and increases the residence time, promoting more complete dechlorination. Solar-powered pumps are suited for the low-yield aquifer beneath Travis AFB and provide a renewable energy source to drive the remediation.

The base is evaluating other innovative technologies that may accelerate the cleanup of the contaminated groundwater. In 1998, the base planted a series of red-bark eucalyptus trees above a portion of the solvent plume downgradient of the bioreactor. These trees are part of an evaluation of phytostabilization, an approach for stopping the migration of a plume. The study concluded in 2009 and demonstrated that the trees were removing contaminant mass from the subsurface and could be a component of an overall groundwater treatment strategy. In 2010, the base installed a biobarrier, which involves the injection of emulsified vegetable oil (EVO) into a row of injection wells located hydraulically downgradient of the 500 μg/L TCE plume and perpendicular to the direction of groundwater flow. These injection wells create an underground reactive zone of EVO. In situ treatment of TCE relies on the natural hydraulic gradient to move contaminated groundwater to and through the biobarrier.

If the innovative technologies prove to be ineffective, the Air Force will install at least one extraction well in the plume to remove dissolved solvents and an extraction well network around the plume to prevent its future migration. The Monitored Natural Attenuation portion of the selected interim remedy is also under review.

Since the site is located in an industrial area, the Air Force has placed a land use control on the property to ensure that it is not used for residential purposes without first addressing the lead residue in the soil.