Technology:
Enhanced In-Situ Anaerobic Bioremediation using Vegetable Oil Substrate
-- Vegetable oil (576 gallons) was emulsified with native groundwater and potable water (1,570 gallons) and was injected into nine locations. This was followed by a water push of additional groundwater into the injection wells (100 gallons per injection point).
-- The emulsion consisted of approximately 25 percent partially hydrogenated soybean oil lecithin and 75 percent native groundwater and potable water. Chromatint fluorescent dye was added to the vegetable oil to track the physical distribution of the emulsion.
-- Injection wells were installed using a Geoprobe® rig with a 1-inch diameter hollow-steel-direct-push rod equipped with an expendable point.
-- Injection rates reached a maximum of 4.7 gallons per minute at a maximum injection pressure of 40 pounds per inch.
-- A cone penetrometer technology rig that was equipped with a laser-induced fluorescence probe and downhole photography capability was used to obtain the radius of influence.
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Cleanup Authority:
Contacts:
AFCEE Project Manager:
Erica S.K. Becvar, M.S.
HQ AFCEE/TDE
3300 Sidney Brooks
Brooks City-Base, TX 78235
(210) 536-4314
erica.becvar@brooks.af.mil
Remediation Contractor:
Bruce M. Henry, P.G.
Parsons
1700 Broadway, Suite 900
Denver, CO 80290
(303) 831-8100
bruce.henry@parsons.com |
Contaminants:
Trichloroethene (TCE); Dichloroethene (DCE); Volatiles-Halogenated |
Waste Source:
Inappropriately discarded landfill materials. |
Type/Quantity of Media Treated:
Groundwater (quantity not documented) |
Purpose/Significance of Application:
To transform the subsurface into a strongly anaerobic environment that could be conducive to the dechlorination of chlorinated solvents in the groundwater. Also to verify that vegetable oil is an appropriate substrate to enhance dechlorination of chlorinated solvents. |
Regulatory Requirements/Cleanup Goals:
Not Specified |
Results:
Geochemical measurements of the subsurface indicated that the vegetable oil emulsion did create anaerobic conditions within the treatment zone; however these areas were sporadic throughout the treatment zone due to substrate distribution and variability in the conditions. Concentrations of TCE increased after injection and DCE remained stable or slightly increased. Vinyl Chloride was not found although ethene did increase approximately one order of magnitude. The duration of the monitoring period was considered not sufficient to observe the dechlorination of chlorinated solvents because of the low groundwater flow rate and low sediment permeability. |
Cost Factors:
The total cost for the pilot test at LF-08 was $117,300 which included $75,700 for capital costs and $41,600 for sample collection and analysis of two monitoring events. |
Description:
LF-08 is located on Whiteman Air Force Base, Missouri, which is 65 miles southeast of Kansas City. It was originally a landfill in the 1940s covering 25,000 square foot area and containing sludge, solvents, paint wastes, lubricating and cutting oils, and dry cleaning filters and filtrates. The site is currently used as a recycling center for the Air Force Base. Contaminants at the site included trichloroethene (TCE) and cis-1, 2-dichloroethene (cis-1,2-DCE).
Enhanced in situ anaerobic bioremediation using vegetable oil substrate was selected as the treatment technology for the pilot study. The vegetable oil emulsion provided an anaerobic environment in which the chlorinated ethenes could reduce but only occurred at some locations within the treatment zone. Because of the short period of time and lack of dechlorination daughter compounds, the duration of the monitoring period was considered insufficient to see the dechlorination of chlorinated solvents. |
