US5384048A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bioremediation of contaminated groundwater
Assignee: United States Department of Energy
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Filing: 1994-03-08
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Granted: 1995-01-24
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Expires: 2014-03-08
Abstract
Abstract An apparatus and method for in situ remediation of contaminated subsurface soil or groundwater contaminated by chlorinated hydrocarbons. A nutrient fluid is selected to stimulate the growth and reproduction of indigenous subsurface microorganisms that are capable of degrading the contaminants; an oxygenated fluid is selected to create a generally aerobic environment for these microorganisms to degrade the contaminants, leaving only pockets that are anaerobic. The nutrient fluid is injected periodically while the oxygenated fluid is injected continuously and both are extracted so that both are drawn across the plume. The nutrient fluid stimulates microbial colony growth; withholding it periodicially forces the larger, healthy colony of microbes to degrade the contaminants. Treatment is continued until the subsurface concentration of contaminants is reduced to an acceptable, preselected level. The nutrient fluid can be methane and the oxygenated fluid air for stimulating production of methanotrophs to break down chlorohydrocarbons, especially trichloroethylene (TCE) and tetrachloroethylene.
Inventors
- 👤 Terry C. Hazen
- 👤 Carl B. Fliermans
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:43
CPC Classifications
C; C02; C02F; C02F3/00; C02F3/02; C02F3/12; C02F3/1205; C02F3/1231; B; B09; B09C; B09C1/00; B09C1/002; C02F3/04; C02F3/046; C02F3/34; B09C2101/00; Y; Y02; Y02E; Y02E50/00; Y02E50/30; Y02W; Y02W10/00; Y02W10/10; Y10; Y10S; Y10S210/00; Y10S210/901
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
151 words
A method for enhancing the degradation of contaminants in soil, said contaminants present at a contaminant concentration, said soil containing microbes capable of degrading said contaminants aerobically, said microbes present at a first concentration, said method comprising the steps of: continuously injecting an oxygenated fluid into said soil to establish a generally aerobic environment in said soil, leaving pockets of anaerobic environments in said soil; injecting for a first interval of time a nutrient fluid into said soil to feed said microbes and increase said first concentration to a second concentration higher than said first concentration; then withholding said nutrient fluid so that said microbes are forced to degrade said contaminants; then, when said second concentration has decreased to a third concentration, resuming injection of said nutrient fluid to increase said third concentration; and continuing to inject and then withhold said nutrient until said contaminant concentration is below a preselected level.
Claim 2
Independent Claim
151 words
A method for enhancing the degradation of contaminants in soil, said contaminants present at a contaminant concentration, said soil containing microbes capable of degrading said contaminants aerobically, said microbes present at a first concentration, said method comprising the steps of: continuously injecting an oxygenated fluid into said soil to establish a generally aerobic environment in said soil, leaving pockets of anaerobic environments in said soil; injecting for a first interval of time a nutrient fluid into said soil to feed said microbes and increase said first concentration to a second concentration higher than said first concentration; then withholding said nutrient fluid so that said microbes are forced to degrade said contaminants; then, when said second concentration has decreased to a third concentration, resuming injection of said nutrient fluid to increase said third concentration; and continuing to inject and then withhold said nutrient until said contaminant concentration is below a preselected level.
Claim 3
Dependent Claim
23 words
The method as recited in claim 1, wherein said contaminants are chlorinated hydrocarbons, said microbes are methanotrophs, and said nutrient fluid contains methane.
Claim 4
Dependent Claim
31 words
The method as recited in claim 1, wherein said oxygenated fluid is selected from the group consisting essentially of air, pure oxygen, an oxygen and nitrogen mixture, water vapor and steam.
Claim 5
Dependent Claim
21 words
The method as recited in claim 1, wherein said nutrient fluid contains no more than approximately 4 volume percent of methane.
Claim 6
Dependent Claim
13 words
The method as recited in claim 1, wherein said oxygenated fluid is air.
Claim 7
Dependent Claim
27 words
The method as recited in claim 1, wherein said oxygenated fluid is air and said nutrient fluid contains not more than approximately 4 volume percent of methane.
Claim 8
Dependent Claim
35 words
The method as recited in claim 1, wherein said nutrient fluid contains approximately 1 volume percent of methane and wherein said nutrient fluid injecting step further comprises continuously injecting said nutrient fluid into said soil.
Claim 9
Dependent Claim
17 words
The method as recited in claim 1, wherein said preselected level is approximately 5 parts per billion.
Claim 10
Dependent Claim
25 words
The method as recited in claim 1, wherein said nutrient fluid is injected into said soil until said soil is saturated with said nutrient fluid.
Claim 11
Dependent Claim
18 words
The method as recited in claim 1, wherein said first interval of time is at least one day.
Claim 12
Dependent Claim
37 words
The method as recited in claim 1, wherein said microbes can be characterized by a microbial concentration, and wherein said first interval of time is long enough for said microbial concentration to increase by approximately a million-fold.
Claim 13
Dependent Claim
29 words
The method as recited in claim 1, further comprising the step of establishing a flow of said nutrient fluid and said oxygenated fluid across said contaminants in said soil.
Claim 14
Independent Claim
184 words
A method for enhancing the degradation of contaminants in a plume in soil, said soil containing microbes capable of degrading said contaminants aerobically at a first rate, said contaminants being characterizable by a concentration, said microbes being characterizable by a concentration, said method comprising the steps of: continuously injecting an oxygenated fluid into said soil to establish a generally aerobic environment in said soil, leaving a plurality of anaerobic pockets in said soil; injecting a nutrient fluid into said soil for a first interval of time to feed said microbes so that said microbes grow upon said nutrient fluid and reproduce, thereby increasing said concentration of said microbes; then withholding said nutrient fluid so that, after said microbes consume at least a portion of said nutrient fluid, said microbes degrade said contaminants; while extracting said nutrient fluid and said oxygenated fluid from said soil so as to establish a flow of said nutrient fluid through said plume; monitoring said concentration of microbes; monitoring said concentration of contaminants; and repeating said injecting steps until said concentration of said contaminants is decreased to a preselected level.
Claim 15
Independent Claim
184 words
A method for enhancing the degradation of contaminants in a plume in soil, said soil containing microbes capable of degrading said contaminants aerobically at a first rate, said contaminants being characterizable by a concentration, said microbes being characterizable by a concentration, said method comprising the steps of: continuously injecting an oxygenated fluid into said soil to establish a generally aerobic environment in said soil, leaving a plurality of anaerobic pockets in said soil; injecting a nutrient fluid into said soil for a first interval of time to feed said microbes so that said microbes grow upon said nutrient fluid and reproduce, thereby increasing said concentration of said microbes; then withholding said nutrient fluid so that, after said microbes consume at least a portion of said nutrient fluid, said microbes degrade said contaminants; while extracting said nutrient fluid and said oxygenated fluid from said soil so as to establish a flow of said nutrient fluid through said plume; monitoring said concentration of microbes; monitoring said concentration of contaminants; and repeating said injecting steps until said concentration of said contaminants is decreased to a preselected level.
Claim 16
Dependent Claim
18 words
The method as recited in claim 13, wherein said nutrient fluid contains methane and said microbes are methanotrophs.
Claim 17
Dependent Claim
24 words
The method as recited in claim 13, wherein said nutrient fluid contains approximately 4 volume percent of methane and said oxygenated fluid is air.
Claim 18
Dependent Claim
31 words
The method as recited in claim 13, wherein said oxygenated fluid is selected from the group consisting essentially of air, pure oxygen, an oxygen and nitrogen mixture, water vapor, and steam.
Claim 19
Dependent Claim
35 words
The method as recited in claim 13, wherein said nutrient fluid contains approximately 1 volume percent of methane and wherein said nutrient fluid injecting step further comprises continuously injecting said nutrient fluid into said soil.
Claim 20
Dependent Claim
23 words
The method as recited in claim 13, wherein said first interval of time ends when said plume is saturated with said nutrient fluid.
Claim 21
Dependent Claim
18 words
The method as recited in claim 13, wherein said interval of time is at least a one day.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-01-23 | 1998-07-25 | 1999-01-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-01-23 | 2002-07-25 | 2003-01-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-01-23 | 2006-07-25 | 2007-01-24 | $7700.00 | Window Closed / Lapsed |