Patent US1628939A successfully refreshed from Google Patents.
Patent US3652406A successfully refreshed from Google Patents.
US3652406A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for sewage treatment
Assignee: VALLENBYGGNADSBYRAN AB
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Filing: 1970-04-20
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Granted: 1972-03-28
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Expires: 1990-04-20
Abstract
Abstract A process for biological treatment of sewage is disclosed, characterized by the addition of a high-activated sludge containing a culture of heterotrophical bacteria to the sewage as an inoculum, before or after the inlet of a biological oxidizing means. The high-activated sludge is produced of at least a portion of the separated primary sludge by aeration in a separate cultivating basin.
Inventors
- 👤 Nils K G Westberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:17
CPC Classifications
C; C02; C02F; C02F3/00; C02F3/02; C02F3/12; C02F3/1205; C02F3/1215; C02F3/006; C02F3/22; C02F3/223; C02F3/34; C02F3/348; Y; Y02; Y02W; Y02W10/00; Y02W10/10
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
22 words
The method of treating sewage according to claim 1, wherein said primary sludge is homogenized before being cultivated in said cultivating tank.
Claim 2
Dependent Claim
57 words
The method of treating sewage according to claim 1, wherein said primary sludge during the cultivation process is subjected to such an aeration time that the concentration of the liquid phase leaving together with the high-activated sludge will substantially be of the same order of magnitude as the concentration of the water desludged by the pre-sedimentation process.
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) | 1975-03-28 | 1975-09-27 | 1976-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-28 | 1979-09-27 | 1980-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-28 | 1983-09-27 | 1984-03-28 | $7700.00 | Window Closed / Lapsed |