US4280914A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for automatically controlling the detoxification of waste waters containing nitrite ions
Assignee: Evonik Operations GmbH
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Filing: 1979-12-04
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Granted: 1981-07-28
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Expires: 1999-12-04
Abstract
Abstract In the detoxification of waste waters containing nitrite ions by means of hydrogen peroxide the addition of hydrogen peroxide is automatically controllable by adding the hydrogen peroxide continuously or in portions with continuous measurement of the pH and stopping the addition when no further reduction of the pH is caused by it. By control of the hydrogen peroxide addition through the change of the pH it is guaranteed that sufficient hydrogen peroxide is added to reach a complete detoxification of the waste water while on the other hand there is not wasted hydrogen peroxide unnecessarily.
Inventors
- 👤 Helmut Knorre
- 👤 Joachim Fischer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 00:06
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/72; C02F1/722; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/903
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
67 words
In a process for the detoxification of nitrite ion containing waste water by oxidizing the nitrite ions to nitrate ions in the weakly acid pH range by means of hydrogen peroxide the improvement comprising automatically controlling the detoxification by successively measuring the pH and stopping the addition of hydrogen peroxide when there is no longer a reduction in the pH upon the addition of more hydrogen peroxide.
Claim 2
Dependent Claim
67 words
In a process for the detoxification of nitrite ion containing waste water by oxidizing the nitrite ions to nitrate ions in the weakly acid pH range by means of hydrogen peroxide the improvement comprising automatically controlling the detoxification by successively measuring the pH and stopping the addition of hydrogen peroxide when there is no longer a reduction in the pH upon the addition of more hydrogen peroxide.
Claim 3
Dependent Claim
12 words
The process of claim 1 wherein the hydrogen peroxide is added continuously.
Claim 4
Dependent Claim
14 words
The process of claim 1 wherein the hydrogen peroxide is added in successive portions.
Claim 5
Dependent Claim
36 words
The process of claim 1 wherein the waste water to be detoxified has a pH of above 4 and then is adjusted to a pH of not above 4.0 before the initial addition of hydrogen peroxide.
Claim 6
Dependent Claim
69 words
The process of claim 1 wherein the waste water to be detoxified has a pH of above 4 a first portion of the hydrogen peroxide necessary for the complete oxidation of the nitrite ions present is added at said pH above 4, then the pH is reduced to a pH of not above 4.0 and then the remainder of the hydrogen peroxide required for the complete oxidation is added.
Claim 7
Dependent Claim
15 words
The process of claim 5 wherein said remainder of the hydrogen peroxide is added continuously.
Claim 8
Dependent Claim
16 words
The process of claim 5 wherein said remainder of the hydrogen peroxide is added in portions.
Claim 9
Dependent Claim
24 words
The process of claim 5 wherein the pH at the time of the addition of said first portion of hydrogen peroxide is about 7.0.
Claim 10
Dependent Claim
39 words
The process of claim 5 wherein the hydrogen peroxide is added in portions such that there is added in each portion at least 0.1 gram of hydrogen peroxide, calculated as 100%, per liter of waste water to be detoxified.
Claim 11
Dependent Claim
39 words
The process of claim 4 wherein the hydrogen peroxide is added in portions such that there is added in each portion at least 0.1 gram of hydrogen peroxide, calculated as 100%, per liter of waste water to be detoxified.
Claim 12
Dependent Claim
39 words
The process of claim 1 wherein the hydrogen peroxide is added in portions such that there is added in each portion at least 0.1 gram of hydrogen peroxide, calculated as 100%, per liter of waste water to be detoxified.
Claim 13
Dependent Claim
61 words
The process of claim 11 wherein the portionwise addition of the hydrogen peroxide is controlled electronically in such manner that for each time controlled period of addition there follows a time controlled period of observation, the pH value measured at the end of the period of observation serving in each case as a reference point for the next period of observation.
Claim 14
Dependent Claim
34 words
The process of claim 1 wherein the waste water to be detoxified has a pH of above 4 and then is adjusted to a pH of 3.7 before the initial addition of hydrogen peroxide.
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) | 1984-07-27 | 1985-01-26 | 1985-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-07-27 | 1989-01-26 | 1989-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-07-27 | 1993-01-26 | 1993-07-28 | $7700.00 | Window Closed / Lapsed |