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Environmental Health - Toxic Substances

Toxics Program Remediation Activities

Nitrate Remediation


Testing of Remediation Technologies

Location Massachusetts Military Reservation, Cape Cod, MA
Partners Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University
  • Enhanced In-Situ Biodegradation
  • Above Ground Bioreactor
Contaminants Nitrate

Nitrate contamination is one of our Nation's most ubiquitous ground-water contamination problems. USGS microbiologists and their colleagues have used a two-phase approach to developing remediation strategies for nitrate contamination in ground water. In the field, USGS scientists have been investigating the potential for enhancing denitrification (the reduction of nitrate to nitrogen gas) by injecting sodium formate into the aquifer. Denitrifying bacteria are native to the subsurface, but are usually electron donor-limited. The addition of formate, which can serve as an electron donor for denitrification, overcomes that limitation, thus increasing the extent to which nitrate can be consumed. In the laboratory, USGS scientists are testing a bench-scale model that uses hydrogen in a bioreactor to enhance denitrification. Hydrogen can also serve as an electron donor for special types of denitrifying bacteria. These microorganisms are autotrophs, requiring only carbon dioxide as a carbon source and producing innocuous products (nitrogen gas and water) from the nitrate and hydrogen. A patent application has been filed for the hydrogen bioreactor. The hydrogen bioreactor has many applications. Many drinking-water suppliers are faced with high nitrate concentrations in their source waters and the hydrogen bioreactor could be an effective tool for them to supply safe drinking water to their customers. The reactor could also be used to treat the discharge from confined animal feeding operations.

More Information
  • Richard L. Smith, USGS, National Research Program, Boulder, CO,
  • Denis LeBlanc, USGS, Massachusetts Water Science Center, Northborough, MA,
  • Smith, R.L., 2005, Small-scale hydrogen-oxidizing-denitrifying bioreactor: Washington, D.C., U.S. Government Patent and Trademark Office, United States Patent No. 6,863,815 B1.
  • Smith, R.L., Buckwalter, S.P., Repert, D.A., and Miller, D.N., 2005, Small-scale, hydrogen-oxidizing-denitrifying bioreactor for treatment of nitrate-contaminated drinking water: Water Research, v, 39, p. 2014-2023.
  • Smith, R.L., Miller, D.N., Brooks, M.H., Widdowson, M.A., and Killingstad, M.W., 2001, In situ stimulation of groundwater denitrification with formate to remediate nitrate contamination: Environmental Science and Technology, v. 35, no. 1, p. 196-203.
  • Killingstad, M.W., Widdowson, M.A., and Smith, R.L., 2002, Modeling enhanced in situ denitrification in groundwater: Journal of Environmental Engineering, v. 128, no. 6, p. 491-504.

Other Toxics Remediation Studies on Cape Cod

Information on Sewage-Contaminated Ground Water

Back to Toxics Program Remediation Activities Index

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