Patent US4174048A successfully refreshed from Google Patents.
Patent US3579439A successfully refreshed from Google Patents.
US3579439A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of sewage
Assignee: South African Inventions Development Corp
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Filing: 1969-05-27
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Granted: 1971-05-18
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Expires: 1989-05-27
Abstract
Abstract THE INVENTION PROVIDES FOR A PROCESS OF AN AN APPARATUS FOR THE TREATMENT OF SEWAGE ACCORDING TO THE ACTIVATED SLUDGE PROCESS. IN THIS PROCESS AND APPARATUS, RAW SEWAGE MIXED WITH ACTIVATED SLUDGE IS AGITATED IN AN AGITATION ZONE, WHEREAFTER A PORTION OF THE MIXTURE IS DIRECTED TO A SETTLING ZONE IN WHICH SLUDGE IS SETTLED OUT, AND THE REMAINDER OF THE MIXTURE IS DIRECTED TO AN ACERATION.
Inventors
- 👤 Pieter Gerhard Jacobus Meiring
- 👤 Peter Hendrik Huisman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 06:14
CPC Classifications
C; C02; C02F; C02F3/00; C02F3/30; C02F3/302; C02F3/006; C02F3/301; Y; Y10; Y10S; Y10S210/00; Y10S210/918; Y10S210/926
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-17 | 1974-11-16 | 1975-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-17 | 1978-11-16 | 1979-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-17 | 1982-11-16 | 1983-05-18 | $7700.00 | Window Closed / Lapsed |