US4765902A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for in situ biodegradation of hydrocarbon contaminated soil
Assignee: Chevron USA Inc
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Filing: 1987-09-25
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Granted: 1988-08-23
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Expires: 2007-09-25
Abstract
Abstract The present invention is a process for in situ biodegradation of spilled hydrocarbons. The process involves drawing oxygen into a hydrocarbon contaminated zone. A borehole is drilled into the contaminated zone and gas is evacuated at high rates out of the borehole to thereby draw oxygen into the contaminated zone. Surprisingly, the carbon dioxide concentration in the evacuated gas remains high even at the high flow rates.
Inventors
- 👤 Douglas L. Ely
- 👤 David A. Heffner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 03:55
CPC Classifications
B; B09; B09C; B09C1/00; B09C1/10; C; C02; C02F; C02F3/00; C02F3/34; Y; Y10; Y10S; Y10S210/00; Y10S210/901
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
150 words
A process for biodegrading hydrocarbons by drawing oxygen into a hydrocarbon contaminated zone, comprising: establishing a borehole from the earth's surface, through a hydrocarbon contaminated zone having hydrocarbon degrading microbes; establishing a fluid impermeable lining, coaxially spaced and sealingly connected to the inside surface of the borehole, extending from the earth surface to the hydrocarbon-contaminated zone; establishing a fluid permeable lining, coaxially spaced within the inside of the borehole, fixedly connected to, and extending from, the end of the fluid impermeable lining; fluidly connecting a source of negative pressure to the fluid impermeable lining; evacuating gas from the fluid permeable lining to draw oxygen into the hydrocarbon-contaminated zone; monitoring the oxygen, total hydrocarbon, and carbon dioxide content of the evacuated gas; and adjusting the flow rate of evacuated gas out of the borehole to between 30 and 250 SCFM per borehole so that a substantial amount of hydrocarbons are biodegraded.
Claim 2
Dependent Claim
150 words
A process for biodegrading hydrocarbons by drawing oxygen into a hydrocarbon contaminated zone, comprising: establishing a borehole from the earth's surface, through a hydrocarbon contaminated zone having hydrocarbon degrading microbes; establishing a fluid impermeable lining, coaxially spaced and sealingly connected to the inside surface of the borehole, extending from the earth surface to the hydrocarbon-contaminated zone; establishing a fluid permeable lining, coaxially spaced within the inside of the borehole, fixedly connected to, and extending from, the end of the fluid impermeable lining; fluidly connecting a source of negative pressure to the fluid impermeable lining; evacuating gas from the fluid permeable lining to draw oxygen into the hydrocarbon-contaminated zone; monitoring the oxygen, total hydrocarbon, and carbon dioxide content of the evacuated gas; and adjusting the flow rate of evacuated gas out of the borehole to between 30 and 250 SCFM per borehole so that a substantial amount of hydrocarbons are biodegraded.
Claim 3
Dependent Claim
29 words
A process in accordance ith claim 1 wherein the flow rate of evacuated gas is adjusted so that the amount of hydrocarbon biodegradation is within 50% of the maximum.
Claim 4
Dependent Claim
25 words
A process in accordance with claim 1 further comprising adjusting the oxygen and total hycarbon concentrations in the evacuated gas to outside the explosive range.
Claim 5
Dependent Claim
15 words
A process in accordance with claim 1 wherein the borehole extends into a capillary zone.
Claim 6
Dependent Claim
15 words
A process in accordance with claim 1 wherein the borehole extends into the ground water.
Claim 7
Dependent Claim
24 words
A process in accordance with claim 1 further comprising establishing multiple boreholes which are spaced between 5 and 300 feet apart from each other.
Claim 8
Dependent Claim
17 words
A process in accordance with claim 1 further comprising monitoring the water content of the evacuated gas
Claim 9
Dependent Claim
22 words
A process in accordance with claim 1 wherein the hydrocarbons that are biodegraded have a boiling point between 90 and 1500° F.
Claim 10
Dependent Claim
25 words
A process in accordance with claim 1 wherein the internal diameter of said fluid permeable and fluid impermeable linings is between 2 and 16 inches.
Claim 11
Dependent Claim
30 words
A process in accordance with claim 1 further comprising adding nutrients which promote bacterial growth to the hydrocarbon contaminated zone, selected from the group of phosphates, nitrates, or alkali metals.
Claim 12
Dependent Claim
15 words
A process in accordance with claim 1 further comprising removing hydrocarbons by creating an aerosol.
References Cited (Backward Citations)
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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) | 1991-08-23 | 1992-02-22 | 1992-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-23 | 1996-02-22 | 1996-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-23 | 2000-02-22 | 2000-08-23 | $7700.00 | Window Closed / Lapsed |