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US5294348A
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Process for removing ammonia from waste waters
Assignee: Societe National Elf Aquitaine
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Filing: 1991-11-25
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Granted: 1994-03-15
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Expires: 2011-11-25
Abstract
Abstract A method for removing ammonia, or ammonia and phosphates from industrial agricultural or household effluents by causing precipitation as magnesium ammonium phosphate by means of a liquid reagent containing magnesium and phosphate ions and an acid. The effluents have more than 1 gle of ammoniacal nitrogen and the pH is adjusted to between 9 and 11 after addition of the liquid reagent.
Inventors
- 👤 Patrick Horny
- 👤 Alain Ladousse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:45
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/58; C02F1/586; C02F1/52; C02F1/5236; C02F1/5254; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/903; Y10S210/906
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
66 words
A process for removing ammoniacal nitrogen contained in waste waters having more than 1 g/l of nitrogen in the ammoniacal form by precipitation in the form of a magnesium ammonium phosphate, comprising the addition to the waste waters of a single liquid reactant containing sources of magnesium ions, phosphate ions and an acid, and then adjusting the pH to a value of between 9 and 11.
Claim 2
Dependent Claim
66 words
A process for removing ammoniacal nitrogen contained in waste waters having more than 1 g/l of nitrogen in the ammoniacal form by precipitation in the form of a magnesium ammonium phosphate, comprising the addition to the waste waters of a single liquid reactant containing sources of magnesium ions, phosphate ions and an acid, and then adjusting the pH to a value of between 9 and 11.
Claim 3
Dependent Claim
21 words
The process according to claim 1, wherein the ratio of the phosphate/magnesium ions of the reactant is from 0.5 to 1.5.
Claim 4
Dependent Claim
15 words
The process according to claim 2, wherein the ratio of the phosphate/magnesium ions is 1/1.
Claim 5
Dependent Claim
29 words
The process according to claim 3, wherein the reactant contains between 0.8 and 2 moles of magnesium and of phosphate per mole of ammoniacal nitrogen in the waste waters.
Claim 6
Dependent Claim
26 words
The process according to claim 1, wherein the source of magnesium ions is selected from the group consisting of magnesium oxide, magnesium sulphate, or magnesium chloride.
Claim 7
Dependent Claim
28 words
The process according to claim 1, wherein the source of phosphate ions is selected from the group consisting of phosphoric acid, alkali metal phosphates, and alkaline-earth metal phosphates.
Claim 8
Dependent Claim
25 words
The process according to claim 1, wherein the acid is selected from the group consisting of hydrochloric acid, sulphuric acid, formic acid, and acetic acid.
Claim 9
Dependent Claim
23 words
The process according to claim 1, wherein the quantity of acid is that necessary to obtain a pH of between 1 and 2.
Claim 10
Dependent Claim
21 words
The process according to claim 1, wherein the pH is adjusted with potassium hydroxide solution, sodium hydroxide solution or mixtures thereof.
Claim 11
Dependent Claim
20 words
The process according to claim 1, wherein the pH is adjusted with bases recovered from industrial operations, without prior purification.
Claim 12
Dependent Claim
14 words
The process according to claim 1, wherein the waste waters also contain phosphate ions.
Claim 13
Dependent Claim
17 words
The process according to claim 1, wherein the waste waters are of industrial, agricultural or domestic origin.
Claim 14
Dependent Claim
25 words
The process according to claim 4, wherein the reactant contains between 1.1 and 1.5 moles of magnesium and phosphate per mole of ammonia and nitrogen.
Claim 15
Dependent Claim
15 words
The process according to claim 5, wherein the source of magnesium ions is magnesium oxide.
Claim 16
Dependent Claim
52 words
A process for treating waste waters including the addition to waste waters containing more than 1 g/l of ammoniacal nitrogen, and phosphate, of a single liquid reactant comprising magnesium ions, phosphate ions, and an acid, and then adjusting the pH of the waste waters to a value of between 9 and 11.
Claim 17
Dependent Claim
52 words
A process for treating waste waters including the addition to waste waters containing more than 1 g/l of ammoniacal nitrogen, and phosphate, of a single liquid reactant comprising magnesium ions, phosphate ions, and an acid, and then adjusting the pH of the waste waters to a value of between 9 and 11.
References Cited (Backward Citations)
JPS5388700A
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JPS54127148A
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JPS55157387A
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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) | 1997-03-14 | 1997-09-13 | 1998-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-03-14 | 2001-09-13 | 2002-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-03-14 | 2005-09-13 | 2006-03-15 | $7700.00 | Window Closed / Lapsed |