US4370235A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of treating excess sludge
Assignee: Shinryo Air Conditioning Co Ltd
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Filing: 1980-09-15
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Granted: 1983-01-25
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Expires: 2000-09-15
Abstract
Abstract A method for treating excess sludge, which comprises the steps of mixing an inlet stream of waste water with activated sludge, aerating the resulting mixture, separating the effluent water from the activated sludge to be recycled to the mixing step, passing the resulting excess sludge to a conversion stage, treating therein the cells of microorganisms composing suspended solids in said excess sludge to convert them to an organic liquid by a physical and/or physico-chemical means, passing the resulting organic liquid to a digesting stage in which activated sludge takes the organic liquid as a nutrient, aerobically digesting therein the organic liquid and discharging an effluent from the digesting stage.
Inventors
- 👤 Akira Suzuki
- 👤 Yasumi Shioya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 20:32
CPC Classifications
C; C02; C02F; C02F3/00; C02F3/02; C02F3/12; C02F3/1205; C02F3/1221; C02F1/00; C02F1/72; C02F1/78; Y; Y02; Y02W; Y02W10/00; Y02W10/10
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
100 words
A method of treating all excess activated sludge discharged from an activated sludge treatment process, comprising: passing all of said excess sludge obtained from said process, none of which is to be returned to said activated sludge treating process, to a conversion unit; converting therein the cells of microorganisms in the suspended solids in said excess sludge to an organic liquid by ozonization of the excess sludge; passing the resulting organic liquid to a digesting stage in which activated sludge utilizes the organic liquid as a nutrient; aerobically digesting the organic liquid; and discharging the effluent from the digesting stage.
Claim 2
Independent Claim
100 words
A method of treating all excess activated sludge discharged from an activated sludge treatment process, comprising: passing all of said excess sludge obtained from said process, none of which is to be returned to said activated sludge treating process, to a conversion unit; converting therein the cells of microorganisms in the suspended solids in said excess sludge to an organic liquid by ozonization of the excess sludge; passing the resulting organic liquid to a digesting stage in which activated sludge utilizes the organic liquid as a nutrient; aerobically digesting the organic liquid; and discharging the effluent from the digesting stage.
Claim 3
Independent Claim
120 words
A method of treating all excess activated sludge discharged from an activated sludge treatment process, comprising: passing all of said excess sludge obtained from said process, none of which is to be returned to said activated sludge treating process, to a conversion unit; converting therein the cells of microorganisms in the suspended solids in said excess sludge to an organic liquid by ozonization of the excess sludge; passing the resulting organic liquid to a digesting stage in which activated sludge utilizes the organic liquid as a nutrient; aerobically digesting the organic liquid such that up to in excess of 95% of the solids suspended in said excess activated sludge can be digested; and discharging the effluent from the digesting stage.
Claim 4
Independent Claim
120 words
A method of treating all excess activated sludge discharged from an activated sludge treatment process, comprising: passing all of said excess sludge obtained from said process, none of which is to be returned to said activated sludge treating process, to a conversion unit; converting therein the cells of microorganisms in the suspended solids in said excess sludge to an organic liquid by ozonization of the excess sludge; passing the resulting organic liquid to a digesting stage in which activated sludge utilizes the organic liquid as a nutrient; aerobically digesting the organic liquid such that up to in excess of 95% of the solids suspended in said excess activated sludge can be digested; and discharging the effluent from the digesting stage.
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) | 1986-01-24 | 1986-07-26 | 1987-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-24 | 1990-07-26 | 1991-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-24 | 1994-07-26 | 1995-01-25 | $7700.00 | Window Closed / Lapsed |