In July 2017 the U.S. Army Corps of Engineers Louisville District began a pilot study to treat contaminated groundwater at a Formerly Used Defense Site (FUDS) in Hobart, Indiana.
The goal of the study is to demonstrate a rapid reduction in contamination of a small and shallow groundwater plume containing trichloroethylene (TCE), and expedite the cleanup process at the former Nike C-47 Launch Area.
“We hope the pilot study demonstrates a quick and effective treatment method to reduce TCE concentrations,” said Corey Knox, Louisville District chemist.
This treatment method would be the first for Louisville District for TCE reduction.
The treatment being used includes injecting 110 gallons of a solution, consisting primarily of sodium lactate and microbes with nitrogen, directly into the plume in an effort to reduce TCE concentrations.
The solution is a proprietary blend of neutral pH fatty acids combined with a nutrient blend for use in enhanced anaerobic reductive dechlorination. Reductive dechlorination can occur naturally when microbes are present in the groundwater under the correct geochemical conditions.
The three days of fieldwork in mid-July went well. “The groundwater appeared to achieve complete saturation of the solution which is important to be effective,” said Clayton Hayes, Louisville District project manager. “The upcoming sampling results will tell how successful the pilot study is.”
After completion of the injections, groundwater samples will be taken from three separate groundwater monitoring wells at 14 days and 30 days and will be taken again at the 60-day interval to assess the concentration levels of TCE.
The study will not only assess TCE treatment effectiveness, but also provide insight into field parameters and the extent of solution distribution required for future remedial actions at other sites with similar geological conditions.
A final report this fall will provide the analysis of the results and can be used by the district to determine whether the treatment should be considered as a remedial alternative on other sites.
“This innovative treatment technique promotes an economical, green, and sustainable remediation method that is non-harmful to the environment,” said Hayes.
Nike C-47 was used during the Cold War by the U.S. Army Air Defense Command as a Nike Hercules guided missile site to protect the cities of Chicago and Gary against a possible attack. As part of the FUDS program, the U.S. Army Corps of Engineers Louisville District is managing the cleanup of the site for the Department of Defense and looking for more effective ways to remediate the site.