US3764523A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Nitrification of bod-containing water
Assignee: Union Carbide Corp
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Filing: 1972-05-01
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Granted: 1973-10-09
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Expires: 1992-05-01
Abstract
Abstract A method for removing both carbon and nitrogen food from BODcontaining water by biochemical oxidation using oxygen gas in the presence of activated sludge, where the carbon food and carbonconsuming microorganisms only are removed in a first zone and a feed stream comprising at least the first zone effluent and containing BOD5 of 20-100 ppm. is passed to the nitrification zone where a combined sludge is formed with both carbon and nitrogen-consuming microorganisms.
Inventors
- 👤 M Stankewich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 00:16
CPC Classifications
C; C02; C02F; C02F3/00; C02F3/02; C02F3/12; C02F3/1205; C02F3/1215; C02F1/00; C02F1/52; C02F1/5236; C02F3/26; Y; Y02; Y02W; Y02W10/00; Y02W10/10; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/903
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
75 words
A method according to claim 1 wherein the carbon food, non-viable material and carbon-consuming microorganisms/biomass ratio in said aeration zone is 0.08- 2 pounds BOD5/day x pound volatile suspended solids, said carbon-depleted effluent water comprises the entire feed stream to said nitrification zone and has 25- 100 ppm. BOD5, and the carbon food, non-viable material and carbon-consuming microorganisms/biomass ratio in the nitrification zone is maintained at 0.12- 0.50 pounds BOD5/day x pound volatile suspended solids.
Claim 2
Dependent Claim
47 words
A method according to claim 1 wherein the carbon food, non-viable material and carbon-consuming microorganisms/biomass ratio in said aeration zone is 0.3- 0.8 pounds BOD5/day x pound volatile suspended solids, the feed stream to said nitrification zone comprises said carbon-depleted effluent water and a secondary BOD5 source.
Claim 3
Dependent Claim
32 words
A method according to claim 3 wherein the feed stream to said nitrification zone comprises said carbon-depleted effluent water and a minor portion of said BOD-containing water untreated in said aeration zone.
Claim 4
Dependent Claim
32 words
A method according to claim 3 wherein the feed stream to said nitrification zone comprises said carbon-depleted effluent water and a minor portion of the settled activated sludge from said aeration zone.
Claim 5
Dependent Claim
27 words
A method according to claim 3 wherein the feed stream to said nitrification zone comprises said carbon-depleted effluent water and a minor portion of aeration zone liquor.
Claim 6
Dependent Claim
177 words
A method according to claim 1 wherein said nitrification zone comprises a multiplicity of separate sub-zones; said oxygen feed gas, feed stream and nitrifying sludge recycle are all introduced to a first sub-zone for mixing and simultaneous fluid recirculation therein to form a first oxygenated liquor and a first oxygen-depleted aeration gas, said first oxygenated liquor and said first oxygen-depleted aeration gas are separately withdrawn and each introduced to a second sub-zone for further mixing and simultaneous fluid recirculation therein to form a second further oxygenated liquor and second further oxygen-depleted aeration gas, said second further oxygenated liquor and said second further oxygen-depleted aeration gas are separately withdrawn from said second sub-zone and each introduced to any remaining sub-zones for further mixing and fluid recirculation in the same cocurrent flow direction as said first and second sub-zones, the aeration gas from the final 44 sub-zone is released as said oxygen-depleted aeration gas of at least 20 percent oxygen (by volume) content, and the oxygenated liquor from said final sub-zone is withdrawn for said settling of nitrifying sludge.
Claim 7
Dependent Claim
19 words
A method according to claim 1 wherein said liquid contact time in the nitrification zone is 60- 120 minutes.
Claim 8
Dependent Claim
26 words
A method according to claim 2 wherein the liquid contact time in the nitrification zone is greater than the liquid contact time in the aeration zone.
Claim 9
Dependent Claim
28 words
A method according to claim 1 wherein the sludge retention time (SRT) in the nitrification zone is at least twice the sludge retention time in the aeration zone.
Claim 10
Dependent Claim
20 words
A method according to claim 1 wherein the sludge retention time (SRT) in the nitrification zone is 5- 15 days.
Claim 11
Dependent Claim
22 words
A method according to claim 1 wherein the dissolved oxygen content (DO) of the nitrification zone liquor is maintained at 4-10 ppm.
Claim 12
Dependent Claim
32 words
A method according to claim 1 wherein the nitrification zone liquor has volatile suspended solids (MLVSS) population comprising 2- 25 percent nitrogen-consuming microorganisms and 98- 75 percent carbon-consuming microorganisms and non-viable material.
Claim 13
Dependent Claim
40 words
A method according to claim 2 wherein the carbon-depleted effluent water has 30- 60 ppm. BOD5, and the carbon food and carbon-consuming microorganisms/biomass ratio in the nitrification zone is maintained at 0.2- 0.4 pounds BOD5/day x pound volatile suspended solids.
Claim 14
Dependent Claim
40 words
A method according to claim 3 wherein the carbon-depleted effluent water has 20- 80 ppm. BOD5, and the carbon food and carbon-consuming microorganism/biomass ratio in the nitrification zone is maintained at 0.05- 0.5 pounds BOD5/day x pound volatile suspended solids.
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) | 1976-10-08 | 1977-04-09 | 1977-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-08 | 1981-04-09 | 1981-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-08 | 1985-04-09 | 1985-10-09 | $7700.00 | Window Closed / Lapsed |