US4043936A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Biological denitrification of high concentration nitrate waste
Assignee: Energy Research and Development Administration ERDA
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Filing: 1976-02-24
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Granted: 1977-08-23
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Expires: 1996-02-24
Abstract
Abstract Biological denitrification of nitrate solutions at concentrations of greater than one kilogram nitrate per cubic meter is accomplished anaerobically in an upflow column having as a packing material a support for denitrifying bacteria.
Inventors
- 👤 Chester W. Francis
- 👤 Frank S. Brinkley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:00
CPC Classifications
G; G21; G21F; G21F9/00; G21F9/04; G21F9/06; G21F9/18; C; C02; C02F; C02F3/00; C02F3/28; C02F3/2806; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/903; Y10S210/911; Y10S210/912
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
170 words
A process for removing nitrate ions from an aqueous waste stream having a nitrate concentration in excess of one kilogram nitrate per cubic meter, comprising the steps of: incubating under anaerobic conditions a culture of mixed denitrifying bacteria in the presence of a solution comprising at least 750 grams of nitrate per cubic meter and a biologically effective amount of a first carbon source to produce a culture of incubated mixed denitrifying bacteria; mixing said waste stream with a second source of carbon to form an influent solution; passing said influent solution vertically upward through a packed concially shaped column having as a packing material a support for denitrifying bacteria and having said incubated mixed denitrifying bacteria attached thereto; said conically shaped column having an upper diameter larger than its lower diameter; allowing said influent solution to contact said packing whereby said nitrate ions and said carbon source are converted to carbon dioxide and elemental nitrogen by the incubated denitrifying bacteria; and separating said elemental nitrogen from the influent solution.
Claim 2
Dependent Claim
170 words
A process for removing nitrate ions from an aqueous waste stream having a nitrate concentration in excess of one kilogram nitrate per cubic meter, comprising the steps of: incubating under anaerobic conditions a culture of mixed denitrifying bacteria in the presence of a solution comprising at least 750 grams of nitrate per cubic meter and a biologically effective amount of a first carbon source to produce a culture of incubated mixed denitrifying bacteria; mixing said waste stream with a second source of carbon to form an influent solution; passing said influent solution vertically upward through a packed concially shaped column having as a packing material a support for denitrifying bacteria and having said incubated mixed denitrifying bacteria attached thereto; said conically shaped column having an upper diameter larger than its lower diameter; allowing said influent solution to contact said packing whereby said nitrate ions and said carbon source are converted to carbon dioxide and elemental nitrogen by the incubated denitrifying bacteria; and separating said elemental nitrogen from the influent solution.
Claim 3
Dependent Claim
26 words
The process according to claim 1 wherein said packing is selected from the group consisting of coal, polypropylene rings, ceramic rings, ceramic saddles, and polypropylene saddles.
Claim 4
Dependent Claim
25 words
The process according to claim 1 further including the step of maintaining the pH of said influent solution within the range of 6.4 to 7.0.
Claim 5
Dependent Claim
64 words
The process according to claim 1 wherein said waste stream further comprises heavy metal ions and said heavy metal ions are selected from the group consisting of uranium, cadmium, zinc, and plutonium and said heavy metal ions are retained within said column whereby the effluent streams of said column contains a substantially lower concentration of heavy metal ions and nitrogen than said influent stream.
Claim 6
Dependent Claim
65 words
The process according to claim 1 wherein said incubated culture is provided by anaerobically contacting soil having a pH from 6.5 to 7.5 and a carbon content of from 2 to 5 weight percent with said solution comprising at least 750 grams of nitrate per cubic meter and a biologically effective amount of said second carbon source, said soil containing a mixture of denitrifying bacteria.
Claim 7
Dependent Claim
42 words
The process according to claim 1 wherein said aqueous waste stream contains uranium ions and said uranium ions are retained within said column whereby the effluent streams of said column contain a substantially lower concentration of uranium ions than said influent stream.
Claim 8
Dependent Claim
69 words
The process of claim 1 in which said aqueous waste stream comprises nitrate waste from a UO 2 fuel fabrication plant and containing calcium, phosphorus, zinc, nickel, and cadmium ions; whereby calcium, phosphorous, zinc, nickel, and cadmium ions are retained within said column, causing the effluent streams of said column to contain a substantially lower concentration of said calcium, phosphorus, zinc, nickel, and cadmium ions than said influent stream.
Claim 9
Dependent Claim
18 words
The process of claim 7 in which said aqueous waste stream comprises 7-8 kilogram nitrate per cubic meter.
Claim 10
Dependent Claim
65 words
The process of claim 7 in which said incubated culture is provided by anaerobically contacting soil having a pH from 6.5 to 7.5 and a carbon content of from 2 to 5 weight percent with said solution comprising at least 750 grams of nitrate per cubic meter and a biologically effective amount of said second carbon source, said soil containing a mixture of denitrifying bacteria.
Claim 11
Dependent Claim
12 words
The process according to claim 1 wherein said packing is anthracite coal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-08-22 | 1981-02-21 | 1981-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-22 | 1985-02-21 | 1985-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-22 | 1989-02-21 | 1989-08-23 | $7700.00 | Window Closed / Lapsed |