Patent US4354937A successfully refreshed from Google Patents.
US4354937A
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Process for precipitating heavy metals from wastewater
Assignee: RODOCOCC INNOVATION A CORP OF SWEDEN AB
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Filing: 1980-04-22
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Granted: 1982-10-19
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Expires: 2000-04-22
Abstract
Abstract A process for precipitating heavy metals from wastewater containing sulfate ions by treatment of the water with sulfate reducing bacteria. Said bacteria will reduce the sulfate ions to hydrogen sulfide which in its turn will precipitate the metal ions in the form of metal sulfides. According to the invention the bacteria are cultured in one or more culturing vessels in the presence of a nutritive solution and a portion of the wastewater, and the resulting aqueous solution containing hydrogen sulfide produced by the bacteria is introduced into a precipitation vessel together with the remaining major portion of the wastewater.
Inventors
- 👤 Rolf O. Hallberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:55
CPC Classifications
C; C02; C02F; C02F3/00; C02F3/02; C02F3/12; C02F3/1205; C02F3/1231; C02F1/00; C02F1/52; C02F1/5236; C02F3/34; C02F3/345; C22; C22B; C22B3/00; C22B3/18; Y; Y02; Y02P; Y02P10/00; Y02P10/20; Y02W; Y02W10/00; Y02W10/10; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/911; Y10S210/912
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
94 words
A process for precipitating heavy metals from wastewater containing sulfate ions, wherein the water is treated with sulfate reducing bacteria which reduce the sulfate ions to hydrogen sulfide which in its turn precipitates the metal ions in the form of metal sulfides, wherein the bacteria are cultured in one or more culturing vessels in the presence of a nutritive solution and a portion of the wastewater, and that the resulting aqueous solution containing hydrogen sulfide produced by the bacteria is introduced into a precipitation vessel together with the remaining major portion of the wastewater.
Claim 2
Dependent Claim
94 words
A process for precipitating heavy metals from wastewater containing sulfate ions, wherein the water is treated with sulfate reducing bacteria which reduce the sulfate ions to hydrogen sulfide which in its turn precipitates the metal ions in the form of metal sulfides, wherein the bacteria are cultured in one or more culturing vessels in the presence of a nutritive solution and a portion of the wastewater, and that the resulting aqueous solution containing hydrogen sulfide produced by the bacteria is introduced into a precipitation vessel together with the remaining major portion of the wastewater.
Claim 3
Dependent Claim
16 words
A process as claimed in claim 1 wherein the bacteria are selected as Desulfovibrio or Desulfotomaculum.
Claim 4
Dependent Claim
25 words
A process as claimed in either claim 1 or 2 including maintaining the pH for culturing the bacteria in the range of 5.5 to 9.
Claim 5
Dependent Claim
13 words
A process as claimd in claim 3 wherein the pH is substantially 7.
Claim 6
Dependent Claim
12 words
A process as claimed in claim 3 including affecting agitation during culturing.
Claim 7
Dependent Claim
96 words
A process for precipitating heavy metals from wastewater containing sulfate ions, wherein the water is treated with sulfate reducing bacteria which reduce the sulfate ions to hydrogen sulfide which in its turn precipitates, as a floc, the ions in the form of metal sulfides, wherein the bacteria are cultured in one or more culturing vessels in the presense of a nutritive solution and a portion of the wastewater, and that the resulting aqueous solution containing hydrogen sulfide produced by the bacteria is introduced into a precipitation vessel together with the remaining major portion of the wastewater.
Claim 8
Dependent Claim
96 words
A process for precipitating heavy metals from wastewater containing sulfate ions, wherein the water is treated with sulfate reducing bacteria which reduce the sulfate ions to hydrogen sulfide which in its turn precipitates, as a floc, the ions in the form of metal sulfides, wherein the bacteria are cultured in one or more culturing vessels in the presense of a nutritive solution and a portion of the wastewater, and that the resulting aqueous solution containing hydrogen sulfide produced by the bacteria is introduced into a precipitation vessel together with the remaining major portion of the wastewater.
Claim 9
Dependent Claim
12 words
A process as claimed in claim 6 including effecting agitation during culturing.
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) | 1985-10-18 | 1986-04-19 | 1986-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-10-18 | 1990-04-19 | 1990-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-10-18 | 1994-04-19 | 1994-10-19 | $7700.00 | Window Closed / Lapsed |