Patent US3764524A successfully refreshed from Google Patents.
US3764524A
Expired / Lapsed
US
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Phosphorous removal from wastewater
Assignee: Union Carbide Corp
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Filing: 1972-11-13
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Granted: 1973-10-09
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Expires: 1992-11-13
Abstract
Abstract A method for removing both carbon food and phosphorous pollutant by biochemical oxidation and chemical precipitation using oxygen gas in the presence of activated sludge, where most of the carbon food and pollutant are removed in a first covered zone with the addition of phosphorous-precipitating compound and under high food-to-biomass ratio, and the effluent water is further purified in a second covered zone under low food-to-biomass ratio.
Inventors
- 👤 M Stankewich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:14
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; Y10S210/906
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
115 words
A method according to claim 1 wherein said wastewater feed stream also contains nitrogen food, the food/biomass ratio (b) in said first aeration zone is less than 1.5 pounds BOD5/day X pound volatile suspended solids (MLVSS), the partially treated effluent water from said first aeration zone contains less than 100 ppm. BOD5 and at least most of said nitrogen food, the food/biomass ratio (j) in said second aeration zone is less than 0.5 pounds BOD5/day X pound volatile suspended solids (MLVSS), the volatile suspended solids population of said further oxygenated liquor comprises both 2-40 percent nitrogen-consuming microorganisms and 98-60 percent carbon-consuming microorganisms plus non-viable material so that substantial nitrification occurs in said second aeration zone.
Claim 2
Dependent Claim
50 words
A method according to claim 1 wherein the total mixing and fluid recirculation energy expended in the liquor introductory flow section of said first aeration zone is at least 1.1 times the total mixing and fluid recirculation energy expended in said liquor terminal flow section of said first aeration zone.
Claim 3
Dependent Claim
23 words
A method according to claim 1 wherein the phosphorous-precipitating compound is introduced in said liquor terminal flow section of said first aeration zone.
Claim 4
Dependent Claim
17 words
A method according to claim 1 wherein additional phosphorous-precipitating compound is introduced to said second aeration zone.
Claim 5
Dependent Claim
344 words
A method according to claim 1 wherein said first aeration zone and said second aeration zone each comprise a multiplicity of separate sub-zones; said oxygen feed gas wastewater feed stream and first solids recycle are all introduced to a first sub-zone as said liquor introductory flow section of said first aeration zone for mixing and simultaneous fluid recirculation therein to form a first partially oxygenated liquor and a first oxygen-depleted aeration gas, said first partially 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 to form a second partially oxygenated liquor and second further oxygen-depleted aeration gas, said second partially 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 of said first aeration zone for further mixing and fluid recirculatioN in the same cocurrent flow direction as said first and second sub-zones, said phosphorous-precipitating compound is introduced to the final sub-zone as said liquor terminal flow section, the aeration gas from the final sub-zone is released as said oxygen-depleted aeration gas; said oxygen feed gas, partially treated effluent water and second solids recycle are all introduced to a first sub-zone as said liquor introductory flow section of said second aeration zone for mixing and simultaneous fluid recirculation therein to form a first further oxygenated liquor and a first oxygen-depleted aeration gas, said first further 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 to form a second further oxygenated liquor and a second oxygen-depleted aeration gas, said second further oxygenated liquor and said second oxygen-depleted aeration gas are separately withdrawn from said second sub-zone and each introduced to any remaining sub-zones of said second aeration zone 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 sub-zone is released as said oxygen-depleted aeration gas.
Claim 6
Dependent Claim
46 words
A method according to claim 1 wherein the total mixing and fluid recirculation energy expended in said first aeration zone liquor terminal flow section does not exceed 0.25 horsepower/1, 000 U.S. gallons including a high shear part of such energy not exceeding 0.20 horsepower/1,000 U.S. gallons.
Claim 7
Dependent Claim
46 words
A method according to claim 1 wherein the total mixing and fluid recirculation energy expended in said second aeration zone liquor terminal flow section does not exceed 0.20 horsepower/1, 000 U.S. gallons including a high shear part of such energy not exceeding 0.15 horsepower/1,000 U.S. gallon.
Claim 8
Dependent Claim
31 words
A method according to claim 1 wherein the total mixing and fluid recirculation energy expended in the first aeration zone liquor introductory flow section does not exceed 0.50 horsepower/1,000 U.S. gallons.
Claim 9
Dependent Claim
28 words
A method according to claim 1 wherein the food/biomass ratio (b) in said first aeration zone is less than 1.5 pounds BOD5/day X pound volatile suspended solids (MLVSS).
Claim 10
Dependent Claim
28 words
A method according to claim 1 wherein the food/biomass ratio (g) in said second aeration zone is less than 0.5 pounds BOD5/day X pound volatile suspended solids (MLVSS).
Claim 11
Dependent Claim
13 words
A method according to claim 1 wherein ferric chloride is said phosphorous-precipitating compound.
Claim 12
Dependent Claim
13 words
A method according to claim 1 wherein aluminum sulfate is said phosphorous-precipitating compound.
Claim 13
Dependent Claim
21 words
A method according to claim 1 wherein the pH of the liquor in said first and second aeration zones is 6.0-6.7.
Claim 14
Dependent Claim
26 words
A method according to claim 1 wherein the settled solids from said first aeration zone has a chemical solids/total solids weight ratio of less than 0.50.
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 |