US3901804A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for processing sludge
Assignee: Kanzaki Paper Manufacturing Co Ltd
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Filing: 1973-10-24
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Granted: 1975-08-26
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Expires: 1993-10-24
Abstract
Abstract The pH of the sludge resulting from coagulation-separation treatment of wastewater utilizing a coagulant substantially consisting of a water soluble aluminum compound is adjusted before subjecting the sludge to a wet air oxidation treatment so that the pH of the sludge obtained after said wet air oxidation treatment is either below 1.5 or above 9.0, whereby the coagulant substantially consisting of an aluminum compound can be recovered in the form of a soluble aluminum compound.
Inventors
- 👤 Motohiro Ohuchi
- 👤 Tojiro Kitahori
- 👤 Toshinari Maitoko
- 👤 Katuhiro Mizuguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:47
CPC Classifications
C; C02; C02F; C02F11/00; C02F11/06; C02F11/08; C02F1/00; C02F1/52; C02F1/5236; C02F1/54
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
89 words
IN A METHOD OF TREATING WASTEWATER WHEREIN THE WASTEWATER IS TREATED WITH A COAGULANT CONSISTING ESSENTIALLY OF A WATER SOLUBLE ALUMINUM COMPOUND AND SLUDGE RESULTING FROM SUCH TREATMENT IS SEPARATED AND SUBJECTED TO A WET AIR OXIDATION TREATMENT, THE IMPROVEMENT COMPRISING ADJUSTING THE PH OF THE SLUDGE PRIOR TO SAID WET AIR OXIDATION TREATMENT SO THAT THE SLUDGE OBTAINED THEREFROM HAS A PH VALUE OF LESS THAN ABOUT 1.5, WHEREBY WATER-SOLUBLE ALUMINUM COMPOUNDS ARE FROMED IN THE OXIDIZED SLUDGE, AND THEREAFTER SEPARATING SAID WATERSOLUBLE ALUMINUM COMPOUNDS FROM THE SLUDGE.
Claim 2
Dependent Claim
89 words
IN A METHOD OF TREATING WASTEWATER WHEREIN THE WASTEWATER IS TREATED WITH A COAGULANT CONSISTING ESSENTIALLY OF A WATER SOLUBLE ALUMINUM COMPOUND AND SLUDGE RESULTING FROM SUCH TREATMENT IS SEPARATED AND SUBJECTED TO A WET AIR OXIDATION TREATMENT, THE IMPROVEMENT COMPRISING ADJUSTING THE PH OF THE SLUDGE PRIOR TO SAID WET AIR OXIDATION TREATMENT SO THAT THE SLUDGE OBTAINED THEREFROM HAS A PH VALUE OF LESS THAN ABOUT 1.5, WHEREBY WATER-SOLUBLE ALUMINUM COMPOUNDS ARE FROMED IN THE OXIDIZED SLUDGE, AND THEREAFTER SEPARATING SAID WATERSOLUBLE ALUMINUM COMPOUNDS FROM THE SLUDGE.
Claim 3
Dependent Claim
32 words
A method of treating wastewater according to claim 1 in which said coagulant is selected from the group consisting of aluminum sulfate, aluminum chloride, sodium aluminate alum, polyaluminum chloride, and mixtures thereof.
Claim 4
Dependent Claim
38 words
A method of treating waStewater according to claim 1 in which said coagulant is used together with a flocculation aid selected from the group consisting of calcium hydroxide, soda ash, active silica, polyacrylamide, sodium polyacrylate, and polyvinylpyridine hydrochloride.
Claim 5
Dependent Claim
89 words
In a method of treating wastewater wherein the wastewater is treated with a coagulant consisting essentially of a water-soluble aluminum compound and sludge resulting from such treatment is separated and subjected to a wet air oxidation treatment, the improvement comprising adjusting the pH of the sludge prior to said wet air oxidation treatment so that the sludge obtained therefrom has a pH value within the range of about 9.0 to 10.5, whereby aluminum hydroxide is formed in the oxidized sludge, and thereafter separating said aluminum hydroxide from the sludge.
Claim 6
Dependent Claim
89 words
In a method of treating wastewater wherein the wastewater is treated with a coagulant consisting essentially of a water-soluble aluminum compound and sludge resulting from such treatment is separated and subjected to a wet air oxidation treatment, the improvement comprising adjusting the pH of the sludge prior to said wet air oxidation treatment so that the sludge obtained therefrom has a pH value within the range of about 9.0 to 10.5, whereby aluminum hydroxide is formed in the oxidized sludge, and thereafter separating said aluminum hydroxide from the sludge.
Claim 7
Dependent Claim
40 words
A method of treating wastewater according to claim 4 wherein said improvement includes the further step of adding an acid or alkali to said sludge obtained after said wet air oxidation treatment to dissolve aluminum hydroxide included in said sludge.
Claim 8
Dependent Claim
32 words
A method of treating wastewater according to claim 1 in which said coagulant is selected from the group consisting of aluminum sulfate, aluminum chloride, sodium aluminate alum, polyaluminum chloride, and mixtures thereof.
Claim 9
Dependent Claim
38 words
A method of treating wastewater according to claim 4 in which said coagulant is used together with a flocculation aid selected from the group consisting of calcium hydroxide, soda ash, active silica, polyacrylamide, sodium polyacrylate, and polyvinylpyridine hydrochloride.
Claim 10
Dependent Claim
26 words
IN A METHOD OF TREATING WASTEWATER WHEREIN THE WASTEWATER IS TREATED WITH A COALGULANT CONSISTING ESSENTIALLY OF A WATERSOLUBLE ALUMINUM COMPOUND AND SLUDGE RESULTING FROM SUCH
Claim 11
Dependent Claim
26 words
IN A METHOD OF TREATING WASTEWATER WHEREIN THE WASTEWATER IS TREATED WITH A COALGULANT CONSISTING ESSENTIALLY OF A WATERSOLUBLE ALUMINUM COMPOUND AND SLUDGE RESULTING FROM SUCH
Claim 12
Dependent Claim
32 words
A method of treating wastewater according to claim 8 in which said coagulant is selected from the group consisting of aluminum sulfate, aluminum chloride, sodium aluminate alum, polyaluminum chloride, and mixtures thereof.
Claim 13
Dependent Claim
39 words
A method of treating wastewater according to claim 8 in which said coagulant is used together with a flocculation aid selected from the group consisting of calcium hydroxide, soda ash, active silica, polyacrylamide, sodium polyacrylate, and poly polyvinylpyridine hydrochloride.
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) | 1978-08-25 | 1979-02-24 | 1979-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-25 | 1983-02-24 | 1983-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-25 | 1987-02-24 | 1987-08-26 | $7700.00 | Window Closed / Lapsed |