US3655552A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for removing phosphate from waste water
Assignee: Calgon Corp
•
Filing: 1971-02-16
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Granted: 1972-04-11
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Expires: 1991-02-16
Abstract
Abstract Phosphate is removed from municipal and industrial waste water by treating the water with a synergistic admixture of a watersoluble high molecular weight nonionic polymer, preferably polyacrylamide, and a water-soluble salt containing ferric ions, preferably ferric chloride.
Inventors
- 👤 Howard George Flock Jr
- 👤 Emerson George Rausch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 06:56
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/52; C02F1/54; C02F1/5236; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/906
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
14 words
A method as in claim 1 wherein the polymer is a homopolymer of acrylamide.
Claim 2
Dependent Claim
19 words
A method as in claim 1 wherein the iron containing salt is selected from ferric sulfate and ferric chloride.
Claim 3
Dependent Claim
19 words
A method as in claim 2 wherein the iron containing salt is selected from ferric sulfate and ferric chloride.
Claim 4
Independent Claim
96 words
A method for removing phosphate from water comprising: a. first forming an aqueous blend of a water-soluble, high molecular weight polymer consisting essentially of nonionic polyacrylamide containing not more than about three percent carboxyl groups and a water-soluble, iron containing salt where the liquid blend, exclusive of water, consists essentially of from 0.01 to 2.0 percent by weight of the polymer and the remainder the water-soluble, iron containing salt; and b. thereafter treating the water with from 0.5 to 3.0 p.p.m. of the liquid blend for every 1 p.p.m. of dissolved phosphate present in the water.
Claim 5
Dependent Claim
23 words
A method as in claim 5 wherein the polymer is a homopolymer of acrylamide and wherein the iron containing salt is ferric chloride.
References Cited (Backward Citations)
CA607440A
Cited
GB805526A
Cited
US3171804A
Cited
US3232793A
Cited
US3461067A
Cited
US3488717A
Cited
US3506570A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-04-11 | 1975-10-11 | 1976-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-11 | 1979-10-11 | 1980-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-11 | 1983-10-11 | 1984-04-11 | $7700.00 | Window Closed / Lapsed |