Patent US3994804A successfully refreshed from Google Patents.
US3994804A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sewage sludge treatment system
Assignee: California Institute of Technology
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Filing: 1976-01-16
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Granted: 1976-11-30
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Expires: 1996-01-16
Abstract
Abstract Raw sewage may be presently treated by mixing screened raw sewage with activated carbon. The mixture is then allowed to stand in a first tank for a period required to settle the suspended matter to the bottom of the tank as a sludge. Thereafter, the remaining liquid is again mixed with activated carbon and the mixture is transferred to a secondary settling tank, where it is permitted to stand for a period required for the remaining floating material to settle as sludge and for adsorption of sewage carbon as well as other impurities to take place. The sludge from the bottom of both tanks is removed and pyrolyzed to form activated carbon and ash, which is mixed with the incoming raw sewage and also mixed with the liquid being transferred from the primary to the secondary settling tank. It has been found that the output obtained by the pyrolysis process contains an excess amount of ash. Removal of this excess amount of ash usually also results in removing an excess amount of carbon thereby requiring adding carbon to maintain the treatment process. By separately pyrolyzing the respective sludges from the first and second settling tanks, and returning the separately obtained pyrolyzed material to the respective first and second tanks from which they came, it has been found that the adverse effects of the excessive ash buildup is minimized, the carbon yield is increased, and the sludge from the secondary tank can be pyrolyzed into activated carbon to be used as indicated many more times than was done before exhaustion occurs.
Inventors
- 👤 John J. Kalvinskas
- 👤 William A. Mueller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:16
CPC Classifications
C; C02; C02F; C02F11/00; C02F11/10; B; B01; B01D; B01D21/00; C01; C01B; C01B32/00; C01B32/30; C01B32/312; C01B32/318; C01B32/324; C02F9/00; Y; Y02; Y02W; Y02W10/00; Y02W10/40
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
184 words
In a method for treatment of raw liquid waste wherein the raw liquid waste includes water in which organic and inorganic matter is dissolved and which contains suspended matter, wherein the raw liquid waste is first mixed with activated carbon and ash, this mixture is then introduced into a primary settling tank for settling the suspended matter as a primary sludge, the effluent from the first settling tank being mixed with activated carbon and ash, which mixture is then supplied to a secondary settling tank to permit the settlement of a secondary sludge therein, the primary and secondary sludges being de-watered and supplied to a pyrolyzer to be formed into the activated carbon and ash mixed with the raw liquid waste and effluent, the improvement comprising separately pyrolyzing the primary sludge and the secondary sludges to form separate quantities of activated carbon and ash, mixing the activated carbon and ash derived by pyrolysis of the primary sludge with the raw liquid waste, and mixing the activated carbon and ash derived by pyrolysis of the secondary sludge with the effluent from the first settling tank.
Claim 2
Dependent Claim
184 words
In a method for treatment of raw liquid waste wherein the raw liquid waste includes water in which organic and inorganic matter is dissolved and which contains suspended matter, wherein the raw liquid waste is first mixed with activated carbon and ash, this mixture is then introduced into a primary settling tank for settling the suspended matter as a primary sludge, the effluent from the first settling tank being mixed with activated carbon and ash, which mixture is then supplied to a secondary settling tank to permit the settlement of a secondary sludge therein, the primary and secondary sludges being de-watered and supplied to a pyrolyzer to be formed into the activated carbon and ash mixed with the raw liquid waste and effluent, the improvement comprising separately pyrolyzing the primary sludge and the secondary sludges to form separate quantities of activated carbon and ash, mixing the activated carbon and ash derived by pyrolysis of the primary sludge with the raw liquid waste, and mixing the activated carbon and ash derived by pyrolysis of the secondary sludge with the effluent from the first settling tank.
Claim 3
Dependent Claim
188 words
In a system for treatment of raw liquid waste wherein the raw liquid waste includes water in which organic and inorganic matter is dissolved and which contains suspended matter, wherein the raw liquid waste is first mixed with activated carbon and ash, this mixture is then introduced into a primary settling tank for settling the suspended matter as a primary sludge, the effluent from the first settling tank being mixed with activated carbon and ash, which mixture is then supplied to a secondary settling tank to permit the settlement of a secondary sludge therein, the primary and secondary sludges being de-watered and supplied to a pyrolyzer to be formed into the activated carbon and ash mixed with the raw liquid waste and effluent, the improvement comprising means for separately pyrolyzing the primary and secondary sludges to form separate quantities of activated carbon and ash, means for mixing the activated carbon and ash derived by pyrolysis of the primary sludge with the raw liquid waste, and means for mixing the activated carbon and ash derived by pyrolysis of the secondary sludge with the effluent from said first settling tank.
Claim 4
Dependent Claim
188 words
In a system for treatment of raw liquid waste wherein the raw liquid waste includes water in which organic and inorganic matter is dissolved and which contains suspended matter, wherein the raw liquid waste is first mixed with activated carbon and ash, this mixture is then introduced into a primary settling tank for settling the suspended matter as a primary sludge, the effluent from the first settling tank being mixed with activated carbon and ash, which mixture is then supplied to a secondary settling tank to permit the settlement of a secondary sludge therein, the primary and secondary sludges being de-watered and supplied to a pyrolyzer to be formed into the activated carbon and ash mixed with the raw liquid waste and effluent, the improvement comprising means for separately pyrolyzing the primary and secondary sludges to form separate quantities of activated carbon and ash, means for mixing the activated carbon and ash derived by pyrolysis of the primary sludge with the raw liquid waste, and means for mixing the activated carbon and ash derived by pyrolysis of the secondary sludge with the effluent from said first settling tank.
Claim 5
Dependent Claim
49 words
In a system as recited in claim 2 wherein said means for separately pyrolyzing the primary and secondary sludges comprises a first pyrolyzing reactor to which only the primary sludge is applied for pyrolysis, and a second pyrolyzing reactor to which only the secondary sludge is applied for pyrolysis.
Claim 6
Dependent Claim
156 words
In a raw liquid waste treatment system of the type wherein the raw liquid waste is mixed with activated carbon and ash which is then allowed to stand in a primary tank for a predetermined period to permit settlement of settleable matter as a primary sludge, the effluent is then removed from said primary tank, is mixed with activated carbon and ash and allowed to stand for a predetermined time in a secondary tank until a secondary sludge settles down, an improvement comprising a first pyrolyzing reactor, means for applying said primary sludge to said first pyrolyzing reactor to produce primary activated carbon and ash means for mixing said primary carbon and ash with said raw liquid waste, a second pyrolyzing reactor, means for applying said secondary sludge to said secondary pyrolyzing reactor to produce secondary activated carbon and ash, and means for mixing said secondary carbon and ash with said effluent from said primary tank.
Claim 7
Dependent Claim
156 words
In a raw liquid waste treatment system of the type wherein the raw liquid waste is mixed with activated carbon and ash which is then allowed to stand in a primary tank for a predetermined period to permit settlement of settleable matter as a primary sludge, the effluent is then removed from said primary tank, is mixed with activated carbon and ash and allowed to stand for a predetermined time in a secondary tank until a secondary sludge settles down, an improvement comprising a first pyrolyzing reactor, means for applying said primary sludge to said first pyrolyzing reactor to produce primary activated carbon and ash means for mixing said primary carbon and ash with said raw liquid waste, a second pyrolyzing reactor, means for applying said secondary sludge to said secondary pyrolyzing reactor to produce secondary activated carbon and ash, and means for mixing said secondary carbon and ash with said effluent from said primary tank.
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) | 1979-11-30 | 1980-05-31 | 1980-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-30 | 1984-05-31 | 1984-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-30 | 1988-05-31 | 1988-11-30 | $7700.00 | Window Closed / Lapsed |