Patent US4231862A successfully refreshed from Google Patents.
US4231862A
Expired / Lapsed
US
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Method for the preservation of an activated sludge
Assignee: Sulzer AG
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Filing: 1979-03-22
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Granted: 1980-11-04
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Expires: 1999-03-22
Abstract
Abstract A method for the preservation of activated sludge of a waste water purification stage, wherein preservation of such activated sludge is accomplished by flushing with a gas mixture containing at least carbon dioxide and a low oxygen content.
Inventors
- 👤 Roberto Mona
- 👤 Jurgen Gnieser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:59
CPC Classifications
C; C02; C02F; C02F3/00; C02F3/02; C02F3/12; C02F3/1205; C02F3/1221; Y; Y02; Y02W; Y02W10/00; Y02W10/10
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
97 words
A method for the preservation of an activated sludge for the reuse in biological waste water purification stages, comprising the steps of: storing activated sludge which is to be preserved and subsequently introduced and used in a biological waste water purification stage; flushing the activated sludge with a gas to preserve the stored activated sludge prior to its use; and using as the flushing gas a gas containing at least carbon dioxide and to the extent that the flushing gas contains oxygen the flushing gas contains at least a reduced amount of oxygen in relation to air.
Claim 2
Independent Claim
97 words
A method for the preservation of an activated sludge for the reuse in biological waste water purification stages, comprising the steps of: storing activated sludge which is to be preserved and subsequently introduced and used in a biological waste water purification stage; flushing the activated sludge with a gas to preserve the stored activated sludge prior to its use; and using as the flushing gas a gas containing at least carbon dioxide and to the extent that the flushing gas contains oxygen the flushing gas contains at least a reduced amount of oxygen in relation to air.
Claim 3
Dependent Claim
34 words
The method as defined in claim 1, further including the steps of: utilizing as the flushing gas a gas containing at most 10% by volume oxygen and at least 10% by volume carbon dioxide.
Claim 4
Dependent Claim
51 words
The method as defined in claim 2, further including the steps of: utilizing as the flushing gas a gas which additionally contains a residual gas selected from at least any one of the rare gases and nitrogen, or mixtures thereof, and present in an amount of up to 90% by volume.
Claim 5
Dependent Claim
21 words
The method as defined in claim 1, further including the steps of: utilizing as the flushing gas industrially pure carbon dioxide.
Claim 6
Dependent Claim
37 words
The method as defined in claim 1, wherein: there is employed as the flushing gas the waste gas of a biological waste water purification stage operated with air or oxygen and according to the activated sludge method.
Claim 7
Dependent Claim
41 words
The method as defined in claim 2, further including the steps of: there is employed as the flushing gas the waste gas of a biological waste water purification stage operated with air or oxygen and according to the activated sludge method.
Claim 8
Dependent Claim
49 words
The method as defined in claim 1, further including the steps of: flushing the preserved activated sludge, prior to its renewed use in an aerobic biological waste water purification stage, for a certain amount of time with a gas whose oxygen content corresponds at least to that of air.
Claim 9
Dependent Claim
21 words
The method as defined in claim 1, further including the steps of: previously concentrating the activated sludge intended to be preserved.
Claim 10
Dependent Claim
25 words
The method as defined in claim 1, further including the steps of: carrying out preservation of the activated sludge while intensively mixing the activated sludge.
Claim 11
Dependent Claim
21 words
The method as defined in claim 9, wherein: there is provided a vessel within which the activated sludge is intensively mixed.
Claim 12
Dependent Claim
25 words
The method as defined in claim 10, further including the steps of: employing for the mixing and the infeed of the gas a static mixer.
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) | 1983-11-04 | 1984-05-05 | 1984-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-04 | 1988-05-05 | 1988-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-04 | 1992-05-05 | 1992-11-04 | $7700.00 | Window Closed / Lapsed |