US4790940A
Expired / Lapsed
US
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Process for wastewater treatment
Assignee: Radian International LLC
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Filing: 1987-11-03
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Granted: 1988-12-13
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Expires: 2007-11-03
Abstract
Abstract Free cyanide-containing wastewater is treated to destroy the free cyanide content thereof by the step of treating said water with sulfur in the form of polysulfide in an integrated process wherein thiocyanate is also eliminated to produce a non-hazardous wastewater effluent and treating the wastewater in a second step with cultures of bacteria of the genus Thiobacillus in combination with nitrifying bacteria which oxidize ammonia to nitrite to nitrate. The first step is preferably carried out in the presence of a cationic surfactant, preferably a quaternary cationic surfactant, as a catalyst.
Inventors
- 👤 Frank J. Castaldi
- 👤 Timothy W. Trofe
- 👤 Gordon C. Page
- 👤 Kevin M. Adams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 18:33
CPC Classifications
C; C02; C02F; C02F3/00; C02F3/34; C02F3/345; C02F3/02; C02F3/12; C02F3/1205; C02F3/1215; C02F2101/00; C02F2101/10; C02F2101/16; C02F2101/18; Y; Y02; Y02W; Y02W10/00; Y02W10/10; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/903; Y10S210/904
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
59 words
A process for the treatment of free cyanide-containing wastewater to destroy the free cyanide content thereof which comprises treating said waters under alkaline conditions with sulfur in the form of polysulfide in a weight ratio of polysulfide to cyanide ranging from 1:1 to 4:1 in the presence of at least 100 mg/l of a cationic surfactant as a catalyst.
Claim 2
Dependent Claim
59 words
A process for the treatment of free cyanide-containing wastewater to destroy the free cyanide content thereof which comprises treating said waters under alkaline conditions with sulfur in the form of polysulfide in a weight ratio of polysulfide to cyanide ranging from 1:1 to 4:1 in the presence of at least 100 mg/l of a cationic surfactant as a catalyst.
Claim 3
Dependent Claim
23 words
A process as defined in claim 1, wherein the polysulfide is an alkali metal polysulfide, ammonium polysulfide, or an alkaline earth metal polysulfide.
Claim 4
Dependent Claim
21 words
A process as defined in claim 1, wherein the reaction is carried out within a pH range of 9.2 to 10.
Claim 5
Dependent Claim
25 words
A process as defined in claim 1, wherein the cationic surfactant is added to the wastewater in the amount of 100 mg/L to 3000 mg/L.
Claim 6
Dependent Claim
16 words
A process as defined in claim 1, wherein the cationic surfactant is a quaternary cationic surfactant.
Claim 7
Dependent Claim
13 words
A process as defined in claim 1, wherein the cationic surfactant is supported.
Claim 8
Dependent Claim
18 words
A process as defined in claim 8, wherein the cationic surfactant is in the form of an organoclay.
Claim 9
Dependent Claim
36 words
A process as defined in claim 7, wherein the quaternary organic component has at least two alkyl groups having a chain length of from 12 to 18 carbon atoms and the clay is a montmorillonite clay.
Claim 10
Dependent Claim
129 words
An integrated process for treating a wastewater containing free cyanide to convert said cyanide to thiocyanate and to eliminate said thiocyanate to produce a non-hazardous wastewater effluent which comprises the steps of treating a wastewater containing free cyanide with sulfur in the form of polysulfide at a pH in the range of 9.2 to 10, in a weight ratio of polysulfide to cyanide ranging from 1:1 to 4:1 and in the presence of at least 100 mg/l of a cationic surfactant as a catalyst, thereafter adjusting the pH to a range of 6.7 to 7.2 and treating the resultant wastewater with a treating agent consisting essentially of cultures of bacteria of the genus Thiobacillus in combination with nitrifying bacteria effective to oxidize ammonia to nitrite and nitrite to nitrate.
Claim 11
Dependent Claim
129 words
An integrated process for treating a wastewater containing free cyanide to convert said cyanide to thiocyanate and to eliminate said thiocyanate to produce a non-hazardous wastewater effluent which comprises the steps of treating a wastewater containing free cyanide with sulfur in the form of polysulfide at a pH in the range of 9.2 to 10, in a weight ratio of polysulfide to cyanide ranging from 1:1 to 4:1 and in the presence of at least 100 mg/l of a cationic surfactant as a catalyst, thereafter adjusting the pH to a range of 6.7 to 7.2 and treating the resultant wastewater with a treating agent consisting essentially of cultures of bacteria of the genus Thiobacillus in combination with nitrifying bacteria effective to oxidize ammonia to nitrite and nitrite to nitrate.
Claim 12
Dependent Claim
18 words
A process as defined in claim 9, wherein the nitrifying bacteria comprise the family of chemoautotrophic bacteria, Nitrobacteraceae.
Claim 13
Dependent Claim
26 words
A process as defined in claim 9, wherein the reaction with polysulfide is carried out in the presence of a quaternary cationic surfactant as a catalyst.
Claim 14
Dependent Claim
24 words
A process as defined in claim 11, wherein the reaction with polysulfide is carried out in the presence of an organoclay as a catalyst.
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) | 1991-12-13 | 1992-06-13 | 1992-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-13 | 1996-06-13 | 1996-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-13 | 2000-06-13 | 2000-12-13 | $7700.00 | Window Closed / Lapsed |