US4125466A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of sludge comprising biological aggregate
Assignee: Tosoh Corp
•
Filing: 1977-05-18
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Granted: 1978-11-14
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Expires: 1997-05-18
Abstract
Abstract A treatment for improving the filtering characteristics of the sludge is attained by adding a magnesium compound with or without an iron salt and further adding a base to maintain the pH of the sludge at higher than 9.0.
Inventors
- 👤 Isao Miyanohara
- 👤 Hiroshi Miyazaki
- 👤 Hideo Kawamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:38
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/52; C02F1/5236; B; B01; B01D; B01D37/00; B01D37/03
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
65 words
A method of treating sludge comprising biological aggregate which comprises adding to said sludge from 5 to 30 wt.% of a magnesium compound selected from the group consisting of magnesium hydroxide, magnesium chloride, magnesium sulfate and magnesium carbonate based on the solid component in said sludge; adding a base to maintain the pH of the sludge at greater than 9.5; and subsequently filtering said sludge.
Claim 2
Independent Claim
65 words
A method of treating sludge comprising biological aggregate which comprises adding to said sludge from 5 to 30 wt.% of a magnesium compound selected from the group consisting of magnesium hydroxide, magnesium chloride, magnesium sulfate and magnesium carbonate based on the solid component in said sludge; adding a base to maintain the pH of the sludge at greater than 9.5; and subsequently filtering said sludge.
Claim 3
Independent Claim
90 words
A method of treating sludge comprising biological aggregate which comprises adding to said sludge from 2 to 15 wt.% of a magnesium compound selected from the group consisting of magnesium hydroxide, magnesium chloride, magnesium sulfate and magnesium carbonate and from 2 to 7 wt.% of an iron salt selected from the group consisting of ferrous chloride, ferric chloride, ferrous sulfate and ferric sulfate based on the solid component in said sludge; adding a base to maintain the pH of the sludge at greater than 9.5; and subsequently filtering said sludge.
Claim 4
Independent Claim
90 words
A method of treating sludge comprising biological aggregate which comprises adding to said sludge from 2 to 15 wt.% of a magnesium compound selected from the group consisting of magnesium hydroxide, magnesium chloride, magnesium sulfate and magnesium carbonate and from 2 to 7 wt.% of an iron salt selected from the group consisting of ferrous chloride, ferric chloride, ferrous sulfate and ferric sulfate based on the solid component in said sludge; adding a base to maintain the pH of the sludge at greater than 9.5; and subsequently filtering said sludge.
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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) | 1981-11-13 | 1982-05-15 | 1982-11-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-11-13 | 1986-05-15 | 1986-11-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-11-13 | 1990-05-15 | 1990-11-14 | $7700.00 | Window Closed / Lapsed |