Patent US4257897A successfully refreshed from Google Patents.
US4257897A
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Process for reabsorption and retention of phosphorous by activated biomass
Assignee: I Kruger Inc
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Filing: 1979-10-26
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Granted: 1981-03-24
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Expires: 1999-10-26
Abstract
Abstract A process for promoting the reabsorption and retention by an activated biomass of phosphorous values previously contained by the biomass and released under anaerobic conditions, which process requires initially subjecting the biomass in admixture with a liquid medium to treatment under aerobic conditions employing a relatively high DO. When the pH of the mixture stops increasing, the aerobic treatment is continued but under a second, reduced DO level.
Inventors
- 👤 David J. Krichten
- 👤 David M. Nicholas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:30
CPC Classifications
C; C02; C02F; C02F3/00; C02F3/02; C02F3/12; C02F3/1205; C02F3/1215; C02F3/121; C02F3/30; C02F3/308; Y; Y02; Y02W; Y02W10/00; Y02W10/10; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/906
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
115 words
A process for promoting the return to and retention by a biomass of phosphorous previously contained by the biomass and released under anaerobic conditions into a liquid medium in admixture with the biomass, the liquid medium having a COD concentration of at least about 100 milligrams per liter, which process comprises subjecting the mixture to treatment under aerobic conditions selected so as initially to maintain a DO content in the range from greater than 3.0 to about 30 mg/l, while there is an increasing pH in the mixture, and when the pH of the mixture ceases to increase, then maintaining a second DO content in the range from less than 3.0 to about 0.5 mg/l.
Claim 2
Dependent Claim
115 words
A process for promoting the return to and retention by a biomass of phosphorous previously contained by the biomass and released under anaerobic conditions into a liquid medium in admixture with the biomass, the liquid medium having a COD concentration of at least about 100 milligrams per liter, which process comprises subjecting the mixture to treatment under aerobic conditions selected so as initially to maintain a DO content in the range from greater than 3.0 to about 30 mg/l, while there is an increasing pH in the mixture, and when the pH of the mixture ceases to increase, then maintaining a second DO content in the range from less than 3.0 to about 0.5 mg/l.
Claim 3
Dependent Claim
16 words
The process of claim 1 wherein the initial DO content is at least about 4 mg/l.
Claim 4
Dependent Claim
16 words
The process of claim 1 wherein the second DO content is less than about 2 mg/l.
Claim 5
Dependent Claim
16 words
The process of claim 1 wherein the initial DO content is less than about 25 mg/l.
Claim 6
Dependent Claim
16 words
The process of claim 1 wherein the second DO content is at least about 1 mg/l.
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) | 1984-03-23 | 1984-09-22 | 1985-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-23 | 1988-09-22 | 1989-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-23 | 1992-09-22 | 1993-03-24 | $7700.00 | Window Closed / Lapsed |