US4279756A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Water clarification
Assignee: Commonwealth Scientific and Industrial Research Organisation
•
Filing: 1978-09-19
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Granted: 1981-07-21
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Expires: 1998-09-19
Abstract
Abstract A particulate coagulant/adsorbent for removing suspended impurities and colored substances from water by coagulation comprises a finely divided particulate mineral or clay material, the individual particles of which have been treated to produce a thin hydroxylated surface layer haivng a positive zeta potential at the adsorption pH. A process and an apparatus for water treatment utilizing the coagulant/adsorbent and providing for regeneration and recycling thereof are also described.
Inventors
- 👤 Donald E. Weiss
- 👤 Luis O. Kolarik
- 👤 Anthony J. Priestley
- 👤 Nevil J. Anderson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:49
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/52; C02F1/5227; B; B01; B01J; B01J20/00; B01J20/02; B01J20/0203; B01J20/0225; B01J20/0229; B01J20/024; B01J20/0244; B01J20/04; B01J20/043; B01J20/045; B01J20/06; B01J20/08; B01J20/10; B01J20/12; B01J20/22; B01J20/26; B01J20/262; B01J20/28; B01J20/28002; B01J20/28004; B01J20/28009; B01J20/28011; B01J20/28014; B01J20/28047; B01J20/30; B01J20/3021; B01J20/32; B01J20/3202; B01J20/3204; B01J20/3231; B01J20/3234; B01J20/3236; B01J20/34; B01J20/3433; B01J20/345; B01J20/3475; C02F1/28; C02F1/281; C02F1/48; C02F1/488; C02F1/5236; C02F1/54; B01J2220/00; B01J2220/40; B01J2220/46; B01J2220/48; B01J2220/4806; B01J2220/50; B01J2220/56
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
143 words
A process for the clarification of water which comprises the steps of: (a) contacting water at pH 3-5 with a coagulant/adsorbent consisting of a finely divided particulate mineral or clay material, the individual particles of which have a particle size of 10 microns or less and have a thin hydroxylated surface layer which has a positive zeta potential at the adsorption pH; (b) separating the water from the coagulant/adsorbent to obtain the clarified water; (c) treating a suspension of the spent coagulant/adsorbent to raise the pH to about 10.5; (d) separating the coagulant/adsorbent from the resulting effluent solution; (e) where necessary regenerating the coagulant/adsorbent by treatment with an alkaline solution; (f) separating the coagulant/adsorbent from the alkaline solution; (g) washing the regenerated coagulant/adsorbent with water; (h) separating the coagulant/adsorbent from the water; and (i) recycling the regenerated and washed coagulant/adsorbent to step (a).
Claim 2
Dependent Claim
143 words
A process for the clarification of water which comprises the steps of: (a) contacting water at pH 3-5 with a coagulant/adsorbent consisting of a finely divided particulate mineral or clay material, the individual particles of which have a particle size of 10 microns or less and have a thin hydroxylated surface layer which has a positive zeta potential at the adsorption pH; (b) separating the water from the coagulant/adsorbent to obtain the clarified water; (c) treating a suspension of the spent coagulant/adsorbent to raise the pH to about 10.5; (d) separating the coagulant/adsorbent from the resulting effluent solution; (e) where necessary regenerating the coagulant/adsorbent by treatment with an alkaline solution; (f) separating the coagulant/adsorbent from the alkaline solution; (g) washing the regenerated coagulant/adsorbent with water; (h) separating the coagulant/adsorbent from the water; and (i) recycling the regenerated and washed coagulant/adsorbent to step (a).
Claim 3
Dependent Claim
20 words
A process as claimed in claim 1 wherein the individual particles have a particle size of 1 to 5 microns.
Claim 4
Dependent Claim
27 words
A process as claimed in claim 1, wherein the washing liquor separated from the coagulant/adsorbent in step (g) is used to raise the pH in step (c).
Claim 5
Dependent Claim
28 words
A process as claimed in claim 1, wherein the coagulant/adsorbent is a magnetic or magnetisable material and the separation steps (d), (f), and (h) are carried out magnetically.
Claim 6
Dependent Claim
139 words
Apparatus for carrying out the process of claim 4, comprising: (a) first mixing and contacting means for contacting water to be treated with the coagulant/adsorbent; (b) separating means for separating the treated water from the spent coagulant/adsorbent; (c) mixing and contacting means for contacting the spent coagulant/adsorbent with dilute alkali for pH adjustment; (d) magnetic separation means for separating the coagulant/adsorbent from the resulting effluent; (e) optionally mixing and contacting means for contacting the coagulant/adsorbent with alkali for regeneration of the coagulant/adsorbent where necessary; (f) magnetic separation means for separating the coagulant/adsorbent from the alkali and recycling the latter to means (e); (g) mixing and contacting means for contacting the coagulant/adsorbent with water for washing; and (h) magnetic separation means for separating the coagulant/adsorbent from the water, recycling the water to means (c) and the coagulant/adsorbent to means (a).
Claim 7
Dependent Claim
33 words
Apparatus as claimed in claim 5, wherein at least one of the mixing and contacting means (a), (c), (e) and (g) comprises a long pipe with turbulent flow conditions therein when in use.
Claim 8
Dependent Claim
16 words
Apparatus as claimed in claim 6, wherein the separating means (b) comprises a solids recirculation clarifier.
Claim 9
Dependent Claim
19 words
A process as claimed in claim 1, wherein alum is added to the water between steps (a) and (b).
Claim 10
Dependent Claim
17 words
A process as claimed in claim 8, wherein alum is recovered from the effluent from step (d).
Claim 11
Independent Claim
78 words
A method for removing suspended impurities and colored substances from water by coagulation which comprises contacting the water at pH 3-5 with a coagulant/adsorbent consisting of a finely divided particulate mineral or clay material, the individual particles of which have a particle size of 10 microns or less and have been treated to produce a thin hydroxylated surface layer having a positive zeta potential at the adsorption pH and then separating the thus treated water from the coagulant/adsorbent.
Claim 12
Independent Claim
78 words
A method for removing suspended impurities and colored substances from water by coagulation which comprises contacting the water at pH 3-5 with a coagulant/adsorbent consisting of a finely divided particulate mineral or clay material, the individual particles of which have a particle size of 10 microns or less and have been treated to produce a thin hydroxylated surface layer having a positive zeta potential at the adsorption pH and then separating the thus treated water from the coagulant/adsorbent.
Claim 13
Dependent Claim
20 words
A method as claimed in claim 10 wherein the individual particles have a particle size of 1 to 5 microns.
Claim 14
Dependent Claim
20 words
A method as claimed in claim 10, wherein the hydroxylated layer is derived from the substance of the particulate material.
Claim 15
Dependent Claim
16 words
A method as claimed in claim 12, wherein the particulate material is an oxide or silicate.
Claim 16
Dependent Claim
17 words
A method as claimed in claim 12, wherein the particulate material is a magnetic or magnetisable material.
Claim 17
Dependent Claim
24 words
A method as claimed in claim 12, wherein the particulate material is selected from the group consisting of gamma iron oxide, magnetite and ferrites.
Claim 18
Dependent Claim
16 words
A method as claimed in claim 10, wherein the hydroxylated layer is derived from another substance.
Claim 19
Dependent Claim
25 words
A method as claimed in claim 16, wherein the particulate material is selected from the group consisting of oxides, sulphates, silicates, carbonate minerals and clays.
Claim 20
Dependent Claim
39 words
A method as claimed in claim 16, wherein the particulate material is selected from the group consisting of calcium sulphate, calcium carbonate, zinc oxide, barium sulphate, silica, sand, glass, mica, china clay, pyrophillite, gamma iron oxide, magnetite and ferrites.
Claim 21
Dependent Claim
22 words
A method as claimed in claim 16, wherein the hydroxylated layer is a metal hydroxide gel which is substantially insoluble in water.
Claim 22
Dependent Claim
18 words
A method as claimed in claim 16, wherein the hydroxylated layer is ferric, aluminium, zicronium or thorium hydroxide.
Claim 23
Dependent Claim
26 words
A method as claimed in claim 10, wherein a substance containing a multi valent cation is added to the water after the coagulant/adsorbent and before separation.
Claim 24
Dependent Claim
20 words
A method according to claim 21 wherein the amount of multivalent cation compound is 5 to 40 mg/l of water.
Claim 25
Dependent Claim
14 words
A method according to claim 22 wherein the multi-valent cation is ferric or aluminum.
Claim 26
Dependent Claim
15 words
A method as claimed in claim 21, wherein the multivalent cation is ferric or aluminium.
Claim 27
Dependent Claim
21 words
A method as claimed in claim 10 wherein a polyelectrolyte is added to the water after the coagulant/adsorbent and before separation.
Claim 28
Dependent Claim
14 words
A method as claimed in claim 25, wherein the polyelectrolyte is a cationic polyelectrolyte.
Claim 29
Dependent Claim
40 words
A method as claimed in claim 10, wherein after separation from the water, the spent coagulant/adsorbent is freed from adsorbent impurities by raising the pH of a suspension of the spent material and separating the coagulant/adsorbent from the resulting solution.
Claim 30
Dependent Claim
29 words
A method as claimed in claim 10, wherein the coagulant adsorbent is regenerated subsequent to or simultaneously with the step of claim 27 by treatment with an alkaline solution.
Claim 31
Dependent Claim
14 words
A method as claimed in claim 10, wherein the coagulant/adsorbent is magnetic or magnestisable.
References Cited (Backward Citations)
GB197806A
Cited
US3499837A
Cited
US3697420A
Cited
US3536198A
Cited
US3549527A
Cited
US3890224A
Cited
US4081365A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-07-20 | 1985-01-19 | 1985-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-07-20 | 1989-01-19 | 1989-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-07-20 | 1993-01-19 | 1993-07-21 | $7700.00 | Window Closed / Lapsed |