In situ bioremediation via horizontal wells. Revision 1
The test consisted of methane mixed with air into the contaminated aquifer via a horizontal well and extraction from the vadose zone via a parallel horizontal well. This configuration has the advantage of simultaneously stimulating methanotrophic activity in both the groundwater and vadose zone, and inhibiting spread of the contaminant plume. Groundwater was monitored biweekly from 13 wells for a variety of chemical and microbiological parameters. Groundwater from wells in affected areas showed increases in methanotrophs of more than 1 order of magnitude every 2 weeks for several weeks after 1% methane-in-air injection was started. Some wells had increases as much as 7 orders of magnitude. Simultaneous with the increase in methanotrophs was a decrease in water and soil gas concentrations of trichloroethylene (TCE) and tetrachloroethane (PCE). Two wells declined in TCE/PCE concentration in the water by more than 90% to below 2 ppb. All of the wells in the affected zone showed significant decreases in contaminants in less than one month. Chloride concentrations in the water were inversely correlated with TCE/PCE concentration. Four of five vadose zone piezometers declined from concentration as high as 10,000 ppm to less than 5 ppm in less than 6 weeks. The fifth cluster also declined by more than 95%. After only three months on injection, a decline in TCE/PCE in the sediment of more than 30% was also observed, with TCE/PCE being undetectable in most sediments at the end of the 14-month test. Gene probes and direct isolation from the water and sediment revealed that the right types of methanotrophs were being stimulated and that isolates could degrade TCE at a high rate.
- Research Organization:
- Westinghouse Savannah River Co., Aiken, SC (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC09-89SR18035
- OSTI ID:
- 10107702
- Report Number(s):
- WSRC-MS-93-362-Rev.1; CONF-9209427-1-Rev.1; ON: DE94004033; TRN: 94:002045
- Resource Relation:
- Conference: Michigan Biotechnology Institute symposium,Grand Rapids, MI (United States),10-15 Sep 1992; Other Information: PBD: [1993]
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
GROUND WATER
CLEANING
CHLORINATED ALIPHATIC HYDROCARBONS
BIODEGRADATION
SOILS
METHANOTROPHIC BACTERIA
REMEDIAL ACTION
ENVIRONMENTAL TRANSPORT
AQUIFERS
540250
540220
560300
SITE RESOURCE AND USE STUDIES
CHEMICALS MONITORING AND TRANSPORT
CHEMICALS METABOLISM AND TOXICOLOGY