• Testing of Remediation Technologies
  
• Performance Monitoring
• Site Characterization

• New Jersey Department of Environmental Protection
• Drexel University, School of Environmental Science, Engineering, and Policy

• Airflow Simulation
• Vapor Extraction

The site of a gasoline spill from a leaking underground storage tank in Galloway Township, New Jersey, served as a test bed for the development of software to model the flow of air in the unsaturated zone. A soil vapor extraction system was set up at the site to develop data sets to test models of airflow in the unsaturated zone. USGS scientists developed two public domain models -- AIR2D and AIR3D. These models provide the tools for practitioners to design and optimize vapor extraction systems. USGS scientists also developed pneumatic tests to collect air permeability data in the unsaturated zone. Data on the distribution of air permeability is needed as an input parameter for the models.

The vapor extraction system at the site successfully reduced concentrations of volatile organic compounds in the unsaturated zone. Monitored natural attenuation was chosen as the final remediation technology for the site. Although the air flow models were not used to optimize the vapor extraction system at this site, the models have been used extensively by the remediation community to design cost efficient vapor extraction systems at contamination sites. The models allowed practitioners to improve the efficiency of their extraction systems to levels that would not have been possible without the airflow models.

• Mathematical Models for Air Flow in the Unsaturated Zone
• How Do You Clean Up Gasoline Spills Naturally?
• Processes Affecting the Natural Attenuation of Gasoline in Ground Water -- Galloway Township, New Jersey
• MTBE Can Degrade Naturally Without Oxygen
• MTBE Biodegrades Naturally in Stream Sediments

Baehr, A.L., and Bruell, C.J., 1990,

Application of the Stefan-Maxwell equations to determine limitations of Fick's Law when modeling organic vapor transport in sand columns: Water Resources Research, v. 26, no. 6, p. 1155-1163.

Baehr, A.L., and Hult, M.F., 1991,

Evaluation of unsaturated zone air permeability through pneumatic tests: Water Resources Research, v. 27, no. 10, p. 2605-2617.

Baehr, A.L., and Joss, C.J., 1995,

An updated model of induced air flow in the unsaturated zone: Water Resources Research, v. 31, no. 2, p. 417-421.

Fischer, J.M., Baker, R.J., Lahvis, M.A., and Baehr, A.L., 1996,

Determination of vapor-phase diffusion coefficients for unsaturated-zone sediments at a gasoline-spill site in Galloway Township, New Jersey, in Morganwalp, D.W., and Aronson, D.A., eds., U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the technical meeting, Colorado Springs, Colorado, September 20-24, 1993: U.S. Geological Survey Water-Resources Investigations Report 94-4015, v. 1, p. 35-41.

Joss, C.J., and Baehr, A.L., 1995,

Documentation of AIR3D, An adaptation of the ground water flow code MODFLOW to simulate three-dimensional airflow in the unsaturated zone: U.S. Geological Survey Open-File Report 94-533, 154 p.

Joss, C.J., and Baehr, A.L., 1996,

A multispecies transport model to simulate vapor extraction and bioventing remediation of unsaturated zones contaminated with gasoline, in Morganwalp, D.W., and Aronson, D.A., eds., U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the technical meeting, Colorado Springs, Colorado, September 20-24, 1993: U.S. Geological Survey Water-Resources Investigations Report 94-4015, v. 1, p. 61-63.

Joss, C.J., and Baehr, A.L., 1997,

AIR2D - A computer code to simulate two-dimensional, radially symmetric airflow in the unsaturated zone: U.S. Geological Survey Open-File Report 97-588, 106 p.

Welty, C., Joss, C.J., and Baehr, A.L., 1996,

Optimizing the design of vapor-extraction remediation systems for removal of organic contaminants from the unsaturated zone, in Morganwalp, D.W., and Aronson, D.A., eds., U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the technical meeting, Colorado Springs, Colorado, September 20-24, 1993: U.S. Geological Survey Water-Resources Investigations Report 94-4015, v. 1, p. 55-59.

Toxics Hydrocarbon Remediation Projects

• Crude Oil Contamination in the Shallow Subsurface -- Bemidji , Minnesota
• Processes Affecting the Natural Attenuation of Fuel Oxygenates in Ground Water -- Laurel Bay, South Carolina
• Processes Affecting the Natural Attenuation of Gasoline in Ground Water - Galloway Township , New Jersey
• Osage-Skiatook Petroleum Environmental Research Project, Oklahoma