Patent US3767570A successfully refreshed from Google Patents.
US3767570A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Granular to powdered activated carbon in polluted water purification process
Assignee: Zeneca Inc
•
Filing: 1971-09-22
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Granted: 1973-10-23
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Expires: 1991-09-22
Abstract
Abstract Process of purifying wastewater by contacting wastewater with an effective amount of spent granular activated carbon that has been ground to a powder. The resulting partially treated wastewater is then substantially separated from the powdered carbon-sludge contained therein and passed through a bed of granular activated carbon. As the granular activated carbon becomes spent, it is ground to a powder for contacting said wastewater.
Inventors
- 👤 K Clapp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 06:48
CPC Classifications
C; C02; C02F; C02F3/00; C02F3/02; C02F3/08; C02F3/085; C02F3/087; Y; Y02; Y02W; Y02W10/00; Y02W10/10
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
33 words
A process of claim 1 wherein the powdered activated carbon is prepared from spent granular activated carbon that has been previously used as a filtering and absorption means in the same treating process.
Claim 2
Dependent Claim
23 words
A process of claim 1 wherein the wastewater is contacted with the powdered activated carbon during the aeration stage of the activated-sludge process.
Claim 3
Dependent Claim
15 words
A process of claim 1 wherein the resulting powdered carbon-sludge is digested aerobically or anaerobically.
Claim 4
Dependent Claim
24 words
A process of claim 1 wherein the powdered spent granular activated carbon will pass through a U.S. Standard mesh of 100 mesh or less.
Claim 5
Dependent Claim
78 words
A sewage treatment process which comprises adding an effective amount of a spent granular activated carbon that has been ground to a powder to the supernatant effluent from a primary settling tank, aerating the resulting mixture, removing settled sludge from the aerated mixture, passing resulting secondary supernatant effluent through a bed of granular activated carbon, and grinding said granular activated carbon that has become spent into a powder for addition to the effluent from said primary settling tank.
Claim 6
Dependent Claim
29 words
A process of claim 6 that is an activated-sludge process wherein the powdered activated carbon and supernatant effluent from a primary settling tank are charged into an aeration tank.
Claim 7
Dependent Claim
30 words
A process of claim 6 that is a trickling filter process wherein the powdered activated carbon and supernatant effluent from a primary settling tank are charged into a trickling-filter system.
Claim 8
Dependent Claim
21 words
A process of claim 6 wherein the mixture being aerated contains about 500 to 5,000 parts per million powdered activated carbon.
Claim 9
Dependent Claim
20 words
A process of claim 7 wherein the mixture being aerated contains about 500 to 5,000 parts per million powdered carbon.
Claim 10
Dependent Claim
40 words
A process of claim 6 wherein the sludge from the primary settling tank and sludge from the settled aerated mixture are digested in mixture with an effective amount of spent granular activated carbon that has been ground to a powder.
Claim 11
Dependent Claim
27 words
A process of claim 11 wherein the sludge being digested contains from about 2 to 20 percent by weight of said powdered carbon, on a dry basis.
Claim 12
Dependent Claim
25 words
A process of claim 6 wherein the powdered spent granular activated carbon will pass through a U.S. Standard mesh screen of 100 mesh or less.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |