US3637487A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sewage treatment process
Assignee: WALCO CHEMICAL CO
•
Filing: 1971-01-11
•
Granted: 1972-01-25
•
Expires: 1991-01-11
Abstract
Abstract A continuous sewage treatment process for upgrading the quality of sewage plant effluent by converting sewage sludges to active substances and returning these active substances to the sewage system whereby removal of dissolved contaminants occurs by the addition of the active substances.
Inventors
- 👤 Frank N Kemmer
- 👤 Reed S Robertson
- 👤 Rodney Mattix
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:46
CPC Classifications
C; C02; C02F; C02F3/00; C02F3/02; C02F3/12; C02F3/1205; C02F3/1226; B; B01; B01D; B01D21/00; B01D21/0012; B01D21/02; B01D21/24; B01D21/2488; C02F1/00; C02F1/28; C02F1/283; C02F1/52; C02F11/00; C02F11/10; C02F9/00; Y; Y02; Y02W; Y02W10/00; Y02W10/10; Y02W10/40
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
17 words
The continuous sewage treatment process of claim 1, in which the acidic phosphorous activating agent is H3PO4.
Claim 2
Dependent Claim
73 words
The continuous sewage treatment process of claim 1, which includes the additional step of: washing said active substance with a liquid selected from group consisting of water and dilute acid to remove the soluble components before returning said active substance to the sewage system, so as to achieve a concentration level greater than 100 p.p.m. in the system whereby removal of the dissolved organic contaminants occurs by the addition of said active substances.
References Cited (Backward Citations)
US1610399A
Cited
US1915240A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-24 | 1975-07-26 | 1976-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-24 | 1979-07-26 | 1980-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-24 | 1983-07-26 | 1984-01-25 | $7700.00 | Window Closed / Lapsed |