US4225430A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Biological process
Assignee: AECI Ltd
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Filing: 1978-06-29
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Granted: 1980-09-30
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Expires: 1998-06-29
Abstract
Abstract A process for denitrifying a highly nitrogenous wastewater in the presence of high concentrations of ammonia is described. The process is based on upflow packed bed and fluidized bed reactors containing denitrifiers on the packing material. A carbon source, e.g. molasses, is metered into the wastewater as a source of carbon and energy to the bacteria. Excess bacteria are removed by hydraulic shear.
Inventors
- 👤 Johanna Bosman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:27
CPC Classifications
C; C02; C02F; C02F3/00; C02F3/28; C02F3/2806; Y; Y02; Y02W; Y02W30/00; Y02W30/40; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/903
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
198 words
A method for denitrifying a high nitrogen content waste water effluent comprising (i) passing a feed of said waste water effluent through a packed bed reactor containing denitrifying bacteria which are heterotrophic and facultative anaerobes on the packing material to denitrify said waste water effluent wherein the feed has a pH of 6 to 7.5, a nitrate nitrogen concentration in excess of 1000 mg/l and ammonia nitrogen in excess of 1000 mg/l and is admixed with molasses, as a carbon source, in an amount sufficient to effect the denitrification of said waste water effluent; and (ii) simultaneously and continuously passing a recycle stream which is a substantially denitrified stream of the waste water feed of (i) through the bed, in a volume such that the volume ratio of recycle stream to feed ranges from 2 to 200 wherein the volume and rate of recycle stream in (ii) are sufficient to effect a linear velocity of the combined feed and recycle stream through the bed ranging from 4 to 200 m 3 /m 2 hr, and to effect a hydraulic shear within the bed which continuously remove accumulated biomass which is in excess of that required to effect denitrification.
Claim 2
Independent Claim
198 words
A method for denitrifying a high nitrogen content waste water effluent comprising (i) passing a feed of said waste water effluent through a packed bed reactor containing denitrifying bacteria which are heterotrophic and facultative anaerobes on the packing material to denitrify said waste water effluent wherein the feed has a pH of 6 to 7.5, a nitrate nitrogen concentration in excess of 1000 mg/l and ammonia nitrogen in excess of 1000 mg/l and is admixed with molasses, as a carbon source, in an amount sufficient to effect the denitrification of said waste water effluent; and (ii) simultaneously and continuously passing a recycle stream which is a substantially denitrified stream of the waste water feed of (i) through the bed, in a volume such that the volume ratio of recycle stream to feed ranges from 2 to 200 wherein the volume and rate of recycle stream in (ii) are sufficient to effect a linear velocity of the combined feed and recycle stream through the bed ranging from 4 to 200 m 3 /m 2 hr, and to effect a hydraulic shear within the bed which continuously remove accumulated biomass which is in excess of that required to effect denitrification.
Claim 3
Dependent Claim
17 words
The method of claim 1, wherein said feed admixed with molasses has a COD:nitrogen value of 4:1.
Claim 4
Dependent Claim
14 words
The method of claim 1, wherein said recycle stream ratio is at least 10:1.
Claim 5
Dependent Claim
11 words
The method of claim 3, wherein the COD:nitrogen ratio is 3:1.
Claim 6
Dependent Claim
25 words
The method of claim 1, wherein said packed bed reactor is a fluidized bed reactor and wherein said linear velocity ranges from 69 to 200.
Claim 7
Dependent Claim
15 words
The method of claim 5, wherein said recycle stream:feed volume ratio is 10:1 to 100:1.
Claim 8
Dependent Claim
20 words
The method of claim 5, wherein sand of a mean particle size of about 0.9 mm diameter forms said bed.
Claim 9
Dependent Claim
35 words
The method of claim 1, wherein the packing material has a voidage in the range 64 to 93 percent and an available surface area in the range 35 to 341 m 2 /m 3 .
Claim 10
Dependent Claim
30 words
The method of claim 8, wherein the voidage is of the order of 90 percent and the surface area is of the order of 140 m 2 /m 3 .
Claim 11
Dependent Claim
20 words
The method of claim 1, wherein the COD:nitrogen ratio of the feed fed to the bed is 6:1 to 3:1.
Claim 12
Dependent Claim
23 words
The method of claim 1, wherein the pH of the feed fed to the reactor in (i) is adjusted to 6 to 7.5.
Claim 13
Dependent Claim
17 words
The method of claim 1, wherein the pH of the feed in (i) is 6 to 7.5.
Claim 14
Dependent Claim
17 words
The method of claim 1, wherein the pH of the feed of (i) does not exceed 9.5.
Claim 15
Dependent Claim
19 words
The method of claim 1, wherein said feed and said recycle stream are passed upwardly through a fluidized bed.
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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) | 1983-09-30 | 1984-03-31 | 1984-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-30 | 1988-03-31 | 1988-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-30 | 1992-03-31 | 1992-09-30 | $7700.00 | Window Closed / Lapsed |