US5118447A
Expired / Lapsed
US
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Thermochemical nitrate destruction
Assignee: Battelle Memorial Institute Inc
•
Filing: 1991-04-12
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Granted: 1992-06-02
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Expires: 2011-04-12
Abstract
Abstract A method is disclosed for denitrification of nitrates and nitrates present in aqueous waste streams. The method comprises the steps of (1) identifying the concentration nitrates and nitrites present in a waste stream, (2) causing formate to be present in the waste stream, (3) heating the mixture to a predetermined reaction temperature from about 200° C. to about 600° C., and (4) holding the mixture and accumulating products at heated and pressurized conditions for a residence time, thereby resulting in nitrogen and carbon dioxide gas, and hydroxides, and reducing the level of nitrates and nitrites to below drinking water standards.
Inventors
- 👤 John L. Cox
- 👤 Richard T. Hallen
- 👤 Michael A. Lilga
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:35
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/70; C02F1/02; C02F1/025; G; G21; G21F; G21F9/00; G21F9/04; G21F9/06; G21F9/14; C02F2101/00; C02F2101/10; C02F2101/16; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/903
Claims Analysis
Total Claims: 56
Claim 1
Independent Claim
90 words
A method of denitrification of nitrates and nitrites in an aqueous stream, comprising the steps of: (a) preparing a mixture by causing formate to be present in the aqueous stream, (b) heating the mixture of step (a) to a predetermined reaction temperature under sufficient pressure to maintain the aqueous stream in an aqueous liquid or supercritical phase, and (c) holding the mixture at the conditions in step (b) for a residence time sufficient to convert the nitrogen in the nitrates and nitrites to nitrogen gas and forming an aqueous product.
Claim 2
Independent Claim
90 words
A method of denitrification of nitrates and nitrites in an aqueous stream, comprising the steps of: (a) preparing a mixture by causing formate to be present in the aqueous stream, (b) heating the mixture of step (a) to a predetermined reaction temperature under sufficient pressure to maintain the aqueous stream in an aqueous liquid or supercritical phase, and (c) holding the mixture at the conditions in step (b) for a residence time sufficient to convert the nitrogen in the nitrates and nitrites to nitrogen gas and forming an aqueous product.
Claim 3
Dependent Claim
23 words
The method as recited in claim 1, further comprising the step of: mixing carbon dioxide with said aqueous product to form a carbonate.
Claim 4
Dependent Claim
18 words
The method as recited in claim 1, wherein formate is caused to be present in the aqueous stream.
Claim 5
Dependent Claim
25 words
The method as recited in claim 1, wherein formate is caused to be present in the aqueous stream by synthesizing formate in the aqueous stream.
Claim 6
Dependent Claim
19 words
The method as recited in claim 1, wherein the aqueous stream has a pH between about 0 to 7.
Claim 7
Dependent Claim
19 words
The method as recited in claim 1, wherein the aqueous stream has a pH between about 7 and 14.
Claim 8
Dependent Claim
20 words
The method as recited in claim 1, wherein the residence time is from about one minute to about two hours.
Claim 9
Dependent Claim
34 words
The method as recited in claim 1, wherein an amount of formate is substantially in stoichiometric ratio to the nitrates and nitrites, resulting in a final concentration of nitrites and nitrates below 44 mg/l.
Claim 10
Dependent Claim
24 words
The method as recited in claim 1, wherein the mixture is heated to a temperature of from about 200° C. to about 600° C.
Claim 11
Dependent Claim
20 words
The method as recited in claim 9, wherein the mixture is heated from about 250° C. to about 350° C.
Claim 12
Dependent Claim
23 words
The method as recited in claim 1, wherein the pressure is from about at least 240 psi to about at least 3200 psi.
Claim 13
Dependent Claim
23 words
The method as recited in claim 11, wherein the pressure is from about at least 580 psi to about at least 2900 psi.
Claim 14
Dependent Claim
18 words
The method as recited in claim 1, wherein the residence time is determined by the predetermined reaction temperature.
Claim 15
Independent Claim
91 words
A method of denitrification of nitrates and nitrites in an aqueous stream, comprising the steps of: (a) heating the aqueous stream to a predetermined reaction temperature under sufficient pressure to maintain the aqueous stream in an aqueous liquid or supercritical phase, (b) preparing a mixture by causing formate to be present in the aqueous stream, and (c) holding the mixture of step (b) at the conditions of step (a) for a residence time sufficient to convert the nitrogen in the nitrates and nitrites to nitrogen gas and form an aqueous product.
Claim 16
Independent Claim
91 words
A method of denitrification of nitrates and nitrites in an aqueous stream, comprising the steps of: (a) heating the aqueous stream to a predetermined reaction temperature under sufficient pressure to maintain the aqueous stream in an aqueous liquid or supercritical phase, (b) preparing a mixture by causing formate to be present in the aqueous stream, and (c) holding the mixture of step (b) at the conditions of step (a) for a residence time sufficient to convert the nitrogen in the nitrates and nitrites to nitrogen gas and form an aqueous product.
Claim 17
Dependent Claim
23 words
The method as recited in claim 14, further comprising the step of: mixing carbon dioxide with said aqueous product to form a carbonate.
Claim 18
Dependent Claim
27 words
The method as recited in claim 14, wherein sodium formate is caused to be present in the aqueous stream by adding sodium formate to the aqueous stream.
Claim 19
Dependent Claim
25 words
The method as recited in claim 14, wherein formate is caused to be present in the aqueous stream by synthesizing formate in the aqueous stream.
Claim 20
Dependent Claim
19 words
The method as recited in claim 14, wherein the aqueous stream has a pH between about 0 and 7.
Claim 21
Dependent Claim
19 words
The method as recited in claim 14, wherein the aqueous stream has a pH between about 7 and 14.
Claim 22
Dependent Claim
20 words
The method as recited in claim 14, wherein the residence time is from about one minute to about two hours.
Claim 23
Dependent Claim
34 words
The method as recited in claim 1, wherein an amount of formate is substantially in stoichiometric ratio with the nitrates and nitrites, resulting in a final concentration of nitrites and nitrates below 44 mg/l.
Claim 24
Dependent Claim
24 words
The method as recited in claim 14, wherein the mixture is heated to a temperature of from about 200° C. to about 600° C.
Claim 25
Dependent Claim
20 words
The method as recited in claim 22, wherein the mixture is heated from about 250° C. to about 350° C.
Claim 26
Dependent Claim
23 words
The method as recited in claim 14, wherein the pressure is from about at least 240 psi to about at least 3200 psi.
Claim 27
Dependent Claim
23 words
The method as recited in claim 24, wherein the pressure is from about at least 580 psi to about at least 2900 psi.
Claim 28
Dependent Claim
18 words
The method as recited in claim 14, wherein the residence time is determined by the predetermined reaction temperature.
Claim 29
Independent Claim
99 words
A method of denitrification of nitrates and nitrites in an aqueous stream, comprising the steps of: (a) preparing a mixture by causing formate to be present in the aqueous stream, (b) heating the mixture of step (a) to a predetermined reaction temperature under sufficient pressure to maintain the aqueous stream in an aqueous liquid or supercritical phase to begin forming reaction products, and (c) holding both the mixture and reaction products at the conditions of step (b) for a residence time sufficient to convert the nitrogen in the nitrates and nitrites to nitrogen gas and form an aqueous product.
Claim 30
Independent Claim
99 words
A method of denitrification of nitrates and nitrites in an aqueous stream, comprising the steps of: (a) preparing a mixture by causing formate to be present in the aqueous stream, (b) heating the mixture of step (a) to a predetermined reaction temperature under sufficient pressure to maintain the aqueous stream in an aqueous liquid or supercritical phase to begin forming reaction products, and (c) holding both the mixture and reaction products at the conditions of step (b) for a residence time sufficient to convert the nitrogen in the nitrates and nitrites to nitrogen gas and form an aqueous product.
Claim 31
Dependent Claim
23 words
The method as recited in claim 27, further comprising the step of: mixing carbon dioxide with said aqueous product to form a carbonate.
Claim 32
Dependent Claim
25 words
The method as recited in claim 27, wherein formate is caused to be present in the aqueous stream by adding formate to the aqueous stream.
Claim 33
Dependent Claim
25 words
The method as recited in claim 27, wherein formate is caused to be present in the aqueous stream by synthesizing formate in the aqueous stream.
Claim 34
Dependent Claim
19 words
The method as recited in claim 27, wherein the aqueous stream has a pH between about 0 and 7.
Claim 35
Dependent Claim
19 words
The method as recited in claim 27, wherein the aqueous stream has a pH between about 7 and 14.
Claim 36
Dependent Claim
20 words
The method as recited in claim 27, wherein the residence time is from about one minute to about two hours.
Claim 37
Dependent Claim
34 words
The method as recited in claim 27, wherein an amount of formate is substantially in stoichiometric ratio to the nitrates and nitrites, resulting in a final concentration of nitrites and nitrates below 44 mg/l.
Claim 38
Dependent Claim
24 words
The method as recited in claim 27, wherein the mixture is heated to a temperature of from about 200° C. to about 600° C.
Claim 39
Dependent Claim
20 words
The method as recited in claim 35, wherein the mixture is heated from about 250° C. to about 350° C.
Claim 40
Dependent Claim
23 words
The method as recited in claim 27, wherein the pressure is from about at least 240 psi to about at least 3200 psi.
Claim 41
Dependent Claim
23 words
The method as recited in claim 37, wherein the pressure is from about at least 580 psi to about at least 2900 psi.
Claim 42
Dependent Claim
18 words
The method as recited in claim 27, wherein the residence time is determined by the predetermined reaction temperature.
Claim 43
Independent Claim
92 words
A method of denitrification of nitrates and nitrites in an aqueous stream, comprising the steps of: (a) heating the aqueous stream to a predetermined reaction temperature under sufficient pressure to maintain the aqueous stream in an aqueous liquid or supercritical phase, (b) causing formate to be present in the aqueous stream, and (c) holding both the mixture of step (b) and accumulating reaction products at the conditions of step (a) for a residence time sufficient to convert the nitrogen in the nitrates and nitrites to nitrogen gas and form an aqueous product.
Claim 44
Independent Claim
92 words
A method of denitrification of nitrates and nitrites in an aqueous stream, comprising the steps of: (a) heating the aqueous stream to a predetermined reaction temperature under sufficient pressure to maintain the aqueous stream in an aqueous liquid or supercritical phase, (b) causing formate to be present in the aqueous stream, and (c) holding both the mixture of step (b) and accumulating reaction products at the conditions of step (a) for a residence time sufficient to convert the nitrogen in the nitrates and nitrites to nitrogen gas and form an aqueous product.
Claim 45
Dependent Claim
23 words
The method as recited in claim 40, further comprising the step of: mixing carbon dioxide with said aqueous product to form a carbonate.
Claim 46
Dependent Claim
25 words
The method as recited in claim 40, wherein formate is caused to be present in the aqueous stream by adding formate to the aqueous stream.
Claim 47
Dependent Claim
25 words
The method as recited in claim 40, wherein formate is caused to be present in the aqueous stream by synthesizing formate in the aqueous stream.
Claim 48
Dependent Claim
19 words
The method as recited in claim 40, wherein the aqueous stream has a pH between about 0 and 7.
Claim 49
Dependent Claim
19 words
The method as recited in claim 40, wherein the aqueous stream has a pH between about 7 and 14.
Claim 50
Dependent Claim
20 words
The method as recited in claim 40, wherein the residence time is from about one minute to about two hours.
Claim 51
Dependent Claim
33 words
The method as recited claim 40, wherein an amount of formate is substantially in stoichiometric ratio to the nitrates and nitrites, resulting in a final concentration of nitrates and nitrites below 44 mg/l.
Claim 52
Dependent Claim
24 words
The method as recited in claim 40, wherein the mixture is heated to a temperature of from about 200° C. to about 600° C.
Claim 53
Dependent Claim
20 words
The method as recited in claim 48, wherein the mixture is heated from about 250° C. to about 350° C.
Claim 54
Dependent Claim
23 words
The method as recited in claim 40, wherein the pressure is from about at least 240 psi to about at least 3200 psi.
Claim 55
Dependent Claim
23 words
The method as recited in claim 50, wherein the pressure is from about at least 580 psi to about at least 2900 psi.
Claim 56
Dependent Claim
18 words
The method as recited in claim 40, wherein the residence time is determined by the predetermined reaction temperature.
References Cited (Backward Citations)
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