• Testing of Remediation Technologies
• Performance Monitoring

• Methyl tert-butyl ether (MTBE)
• Gasoline

USGS scientists have tested the effectiveness of injecting an oxygen-release compound into the subsurface to remediate a plume of methyl tert-butyl ether (MTBE) created by a leaking underground storage tank at a gasoline station at Laurel Bay, SC. The scientists had previously discovered that MTBE naturally biodegrades when the MTBE plume encounters an interface between anoxic (without oxygen) ground water and the oxic (with oxygen) water in stream-bottom sediments. Because ground water is often contaminated with MTBE in locations where such interfaces are not present, the scientists hypothesized that it would be possible to artificially create such an anoxic/oxic interface in anoxic, MTBE-contaminated aquifers. A test was designed using an oxygen-release compound to create an anoxic/oxic interface similar to those found in streambed sediments and to intercept and remediate the leading edge of the MTBE plume. The scientists used wells to inject the oxygen-release compound into the anoxic plume and instrumented the site with observation wells equipped with real-time oxygen probes. Within 60 days following the introduction of oxygen, MTBE concentrations decreased up to 87% from the originally high (> 20 milligrams per liter) concentrations. This test showed that enhanced bioremediation of MTBE-contaminated ground water could be a successful remediation strategy.

Due to the success of the oxygen-release compound test on MTBE, the U.S. Navy, the owner of the site, is interested in testing the technology on some of the less soluble contaminants (toluene, ethylbenzene, and xylene) still present in the source-area of the plume. Remediation of benzene and MTBE contaminants to regulatory compliance levels has been achieved at the Laurel Bay site by dissolution of the free product in the subsurface site followed by natural attenuation processes. However, remediation of less soluble toluene, ethylbenzene, and xylene contaminants may require treatment (or removal) of the source area. USGS scientists plan to treat the source area with an oxygen-release compound to reduce the concentrations of contaminants there. Treatment of the source area will most likely decrease the remediation time associated with the less soluble compounds from the tens of years required for the contaminants to leach out and attenuate to a few years. The source area will be monitored to document the results.

• Processes Affecting the Natural Attenuation of Fuels in Ground Water -- Fuel Oxygenates -- Laurel Bay, South Carolina
• Software Provides Estimates of How Long it Will Take for Remediation Efforts to Achieve Their Goals
• Using Oxygen to Enhance Biodegradation of Contaminants – Lessons Learned
• Oxygen-enhanced bioremediation in a gasolinecontaminated aquifer: Underground Tank Technology Update, 2005, vol. 19, no. 3, p. 4-6.
• MTBE Biodegrades Naturally in Stream Sediments
• MTBE Can Degrade Naturally Without Oxygen
• How Do You Clean Up Gasoline Spills Naturally?
• Oxygen Release Compound (ORC^©) Home Page, Regenesis

Bradley, P.M., Chapelle, F.H. and Landmeyer, J.E., 2001,

MTBE mineralization in surface-water sediment microcosms under denitrifying conditions: Applied and Environmental Microbiology, v. 67, no. 4., p. 1975-1978.

Bradley, P.M., Landmeyer, J.E., and Chapelle, F.H., 2001,

Widespread potential for microbial MTBE degradation in surface-water sediments: Environmental Science and Technology, v. 35, no. 4, p. 658-662.

Landmeyer, J.E., Chapelle, F.H., Herlong, H.H., and Bradley, P.M., 2001,

Methyl tert-butyl ether biodegradation by indigenous aquifer microorganisms under natural and artificial oxic conditions: Environmental Science and Technology, v. 35, n. 6, p. 1118-1126.

Other Toxics Program In-Situ Chemical Oxidation Projects

• Chlorinated Benzene Plume Source Area Containment Test (Oxygen-Release Compound Injection), Naval Air Station, Pensacola, Florida
• Solvent Plume Source Removal Test (Fenton's Reagent), Naval Submarine Base Kings Bay, Georgia
• Subsurface Reactive Barrier, Cape Cod, Massachusetts

Other USGS In-Situ Chemical Oxidation Projects

• Deep Aquifer Remediation Tools (DARTs) -- A New Technology for Ground-Water Remediation (pdf)
• Field Demonstration of Reactive Chemical Barriers to Control Radionuclide and Trace-Element Contamination in Ground Water
  

Toxics Program Information on Remediation of Fuel Oxygenates

• Microorganisms Degrade MTBE Even at Winter Ground-Water Temperatures
• Using Oxygen to Enhance Biodegradation of Contaminants -- Lessons Learned
• Using Oxygen to Clean Up Ground-Water Contamination
• MTBE Can Degrade Naturally Without Oxygen
• MTBE Biodegrades Naturally in Stream Sediments
• Natural Attenuation of MTBE at Laurel Bay, South Carolina
• Processes Affecting the Natural Attenuation of Fuels and Fuel Oxygenates in Ground Water - Laurel Bay, South Carolina
• Oxygen-Release Compound Remediation Tests, Laurel Bay, South Carolina

USGS Information on Fuel Oxygenates

• NAWQA National Synthesis--Volatile Organic Compounds
• The Gasoline Oxygenate Bibliography