Patent US5143767A successfully refreshed from Google Patents.
Patent US4402836A successfully refreshed from Google Patents.
US4402836A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for treating contaminated wastewater
Assignee: United States, AS REPRESENTED BY SECERTARY OF AIR CFORCE
•
Filing: 1982-12-01
•
Granted: 1983-09-06
•
Expires: 2002-12-01
Abstract
Abstract A method for treating hydrazine-fuel contaminated wastewater in which hydrazine, monomethyl hydrazine, unsymmetrical dimethyl hydrazine and dimethylnitrosamine pollutants are effectively decomposed at a controlled pH of about 5 by an ultraviolet induced chlorination treatment of the wastewater.
Inventors
- 👤 Edward G. Fochtman
- 👤 Roger L. Koch
- 👤 Forrest S. Forbes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 05:36
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/72; C02F1/76; C02F1/30; C02F1/32; C02F2101/00; C02F2101/30; C02F2101/32; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/903; Y10S210/908
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
117 words
A method for treating fuel-contaminated wastewater containing hydrazine, monomethyl hydrazine, unsymmetrical dimethyl hydrazine and dimethylnitrosamine pollutants which comprises the steps of: (A) agitating said contaminated wastewater; (B) adjusting and maintaining said agitated wastewater at a predetermined temperature and pH; (C) passing chlorine gas through said agitated wastewater while simultaneously irradiating said chlorine-treated wastewater for a period of time and at a chlorine flow rate and degree of irradiation sufficient to effect the decomposition of said pollutants; (D) reducing the residual chlorine concentration of said chlorine-treated wastewater; (E) dechlorinating said chlorine-treated wastewater to remove any residual chlorine therefrom; and (F) adjusting the pH of said chlorine-treated wastewater to a neutral pH followed by disposal of the decontaminated wastewater.
Claim 2
Independent Claim
117 words
A method for treating fuel-contaminated wastewater containing hydrazine, monomethyl hydrazine, unsymmetrical dimethyl hydrazine and dimethylnitrosamine pollutants which comprises the steps of: (A) agitating said contaminated wastewater; (B) adjusting and maintaining said agitated wastewater at a predetermined temperature and pH; (C) passing chlorine gas through said agitated wastewater while simultaneously irradiating said chlorine-treated wastewater for a period of time and at a chlorine flow rate and degree of irradiation sufficient to effect the decomposition of said pollutants; (D) reducing the residual chlorine concentration of said chlorine-treated wastewater; (E) dechlorinating said chlorine-treated wastewater to remove any residual chlorine therefrom; and (F) adjusting the pH of said chlorine-treated wastewater to a neutral pH followed by disposal of the decontaminated wastewater.
Claim 3
Dependent Claim
28 words
A method in accordance with claim 1 wherein said wastewater is maintained at a temperature ranging from about 40° to 125° C. and a pH of about 5.
Claim 4
Dependent Claim
48 words
A method in accordance with claim 1 wherein said chlorine gas is passed through at a flow rate of about two liters per minute and said degree of irradiation is maintained at about 0.1 to 1.0 watts per liter for a period of about two to three hours.
Claim 5
Dependent Claim
19 words
A method in accordance with claim 3 wherein said chlorine-treated wastewater was irradiated at about 0.9 watts per liter.
Claim 6
Dependent Claim
19 words
A method in accordance with claim 3 wherein said chlorine-treated wastewater was irradiated at about 0.1 watts per liter.
Claim 7
Dependent Claim
25 words
A method in accordance with claim 1 wherein the chlorine concentration of said chlorine-treated wastewater is reduced to about 50 ppm by passing nitrogen therethrough.
Claim 8
Dependent Claim
42 words
A method in accordance with claim 6 wherein said chlorine-treated wastewater is dechlorinated by adding excess Na 2 S 4 O 3 to remove any residual chlorine and adjusted to a pH of about 7 before subsequent disposition to a disposal facility.
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) | 1986-09-05 | 1987-03-07 | 1987-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-05 | 1991-03-07 | 1991-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-05 | 1995-03-07 | 1995-09-06 | $7700.00 | Window Closed / Lapsed |