US4019952A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of purifying the waste water of paper mills
Assignee: Feldmuehle Anlagen und Produktion GmbH
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Filing: 1975-12-12
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Granted: 1977-04-26
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Expires: 1995-12-12
Abstract
Abstract Granular γ-alumina in contact with the waste water of paper mills contaminated with oxygen-demanding, organic substances adsorbs the contaminants, particularly ligninsulfonic acids, and lowers the oxygen demand of the waste water much more effectively than activated charcoal, thereby permitting the purified waste to be fed directly to a secondary biological treatment without damaging the microorganisms.
Inventors
- 👤 Theodor Ploetz, deceased
- 👤 administrator by Adelbert Hasse
- 👤 Volker Franzen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:31
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/28; C02F1/281
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
65 words
A method of purifying waste water of a paper mill of contaminating, oxygen-demanding lignin values which comprises: a. holding granular γ-alumina in contact with said waste water until said lignin values are adsorbed on said alumina and the oxygen demand of said waste water is reduced; and b. separating the waste water of reduced oxygen demand from the alumina having said lignin values adsorbed thereon.
Claim 2
Independent Claim
65 words
A method of purifying waste water of a paper mill of contaminating, oxygen-demanding lignin values which comprises: a. holding granular γ-alumina in contact with said waste water until said lignin values are adsorbed on said alumina and the oxygen demand of said waste water is reduced; and b. separating the waste water of reduced oxygen demand from the alumina having said lignin values adsorbed thereon.
Claim 3
Dependent Claim
17 words
A method as set forth in claim 1, wherein said lignin values consist predominantly of ligninsulfonic acids.
Claim 4
Dependent Claim
30 words
A method as set forth in claim 2, wherein the separated waste water of reduced oxygen demand is contacted with microorganisms capable of metabolizing mono- and oligosaccharides until further purified.
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) | 1980-04-25 | 1980-10-25 | 1981-04-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-25 | 1984-10-25 | 1985-04-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-25 | 1988-10-25 | 1989-04-26 | $7700.00 | Window Closed / Lapsed |