Patent US4011156A successfully refreshed from Google Patents.
US4011156A
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Method for eliminating organic and inorganic bound nitrogen from domestic and industrial waste water
Assignee: Utb Umwelttechnik Buchs AG
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Filing: 1974-07-12
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Granted: 1977-03-08
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Expires: 1994-07-12
Abstract
Abstract A method of eliminating organic and inorganic bound nitrogen from domestic and industrial waste water in a biological waste water treatment plant consisting of two in series connected stages each containing an aeration tank and a subsequently connected settling basin. Waste water entering the treatment plant will be aerated in the first stage aeration tank and subsequently will be introduced for settling into the settling basin, where the overflow is removed free of oxygen and introduced into the second stage where it will be again aerated and subsequently introduced into the settling basin of the second stage. According to the invention there are carried out the steps of aerating the waste water which is free of oxygen containing ammonia and removing it from the settling basin of the first stage to the aeration tank of the second stage while providing favorable conditions for as extensive as possible nitrification of the ammonia, continuously recirculating a portion of the waste water nitrified in this manner from the settling basin of the second stage to the first stage, and denitrifying such recirculated portion of the waste water in the settling basin of the first stage where there are provided favorable conditions for the ammonification of the organic bound nitrogen and for the denitrification of the nitrate in the influent and the nitrate in the recirculated effluents.
Inventors
- 👤 Max Dubach
- 👤 Alfred Scherler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:49
CPC Classifications
C; C02; C02F; C02F3/00; C02F3/02; C02F3/12; C02F3/1205; C02F3/1215; C02F3/34; Y; Y02; Y02W; Y02W10/00; Y02W10/10; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/903; Y10S210/906
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
280 words
A method of eliminating organic and inorganic bound nitrogen from domestic and industrial waste water in a biological activated sludge waste water purification installation capable of directly processing unclarified waste water comprising two stages connected in series for producing biologically treated waste water containing sludge in each stage, each stage containing an aeration tank and a subsequently connected settling basin, wherein the waste water is aerated in the first stage and is subsequently introduced into the settling basin of the first stage where a clarified effluent is transferred into the second stage aeration tank where it is again aerated and subsequently introduced into the settling basin of the second stage, the improvement comprising the steps of: aerating influent waste water containing organic and inorganic bound nitrogen in the aerating tank of the first stage and ammonifying the organic bound nitrogen, transferring the ammonified waste water which also contains nitrates therein to the settling basin of the first stage where denitrification of the nitrate occurs, said aeration step being controlled to maintain a substantially zero oxygen level in the clarified effluent leaving the first stage settling basin, transferring the clarified effluent from the settling basin of the first stage which is substantially free of oxygen and containing ammonia to the aeration tank of the second stage and aerating to an oxygen level of at least about 2mg/l to provide an aerobic condition in the second stage for nitrification of the ammonia to nitrates, continuously recirculating a portion of the clarified effluent from the settling basin of the second stage and which contains nitrates back into the first stage, and denitrifying the recirculated portion of the waste water in the first stage.
Claim 2
Independent Claim
280 words
A method of eliminating organic and inorganic bound nitrogen from domestic and industrial waste water in a biological activated sludge waste water purification installation capable of directly processing unclarified waste water comprising two stages connected in series for producing biologically treated waste water containing sludge in each stage, each stage containing an aeration tank and a subsequently connected settling basin, wherein the waste water is aerated in the first stage and is subsequently introduced into the settling basin of the first stage where a clarified effluent is transferred into the second stage aeration tank where it is again aerated and subsequently introduced into the settling basin of the second stage, the improvement comprising the steps of: aerating influent waste water containing organic and inorganic bound nitrogen in the aerating tank of the first stage and ammonifying the organic bound nitrogen, transferring the ammonified waste water which also contains nitrates therein to the settling basin of the first stage where denitrification of the nitrate occurs, said aeration step being controlled to maintain a substantially zero oxygen level in the clarified effluent leaving the first stage settling basin, transferring the clarified effluent from the settling basin of the first stage which is substantially free of oxygen and containing ammonia to the aeration tank of the second stage and aerating to an oxygen level of at least about 2mg/l to provide an aerobic condition in the second stage for nitrification of the ammonia to nitrates, continuously recirculating a portion of the clarified effluent from the settling basin of the second stage and which contains nitrates back into the first stage, and denitrifying the recirculated portion of the waste water in the first stage.
Claim 3
Dependent Claim
26 words
The method as defined in claim 1, wherein the age of the sludge in the first stage is in the range of 5 to 30 days.
Claim 4
Dependent Claim
42 words
The method as defined in claim 1, including the step of again recycling the sludge present in the settling basin of the first stage after a period of one to eight hours back into the associated aeration tank of such first stage.
Claim 5
Dependent Claim
27 words
The method as defined in claim 3, wherein the amount of recycled sludge per hour amounts to one-fifth to one-half of the volume of the settling basin.
Claim 6
Dependent Claim
35 words
The method as defined in claim 1, including the step of recycling the sludge collecting at the surface of the waste water in the settling basin of the first stage into the aeration tank thereof.
Claim 7
Dependent Claim
32 words
The method as defined in claim 1, including the step of removing as excess sludge the sludge collecting at the surface of the water of the settling basin of the first stage.
Claim 8
Dependent Claim
42 words
The method as defined in claim 1, including the steps of withdrawing sludge from the first stage, mechanically agitating for a period of one to seven hours the sludge withdrawn from the first stage, and thereafter feeding such sludge into a concentrator.
Claim 9
Dependent Claim
28 words
The method as defined in claim 1, including the steps of withdrawing sludge from the first stage, and concentrating the sludge withdrawn from the first stage by flotation.
Claim 10
Dependent Claim
32 words
The method as defined in claim 1, wherein at least no more than one-half of the quantity of sludge present in the second stage is continuously located in the settling basin thereof.
Claim 11
Dependent Claim
23 words
The method as defined in claim 1, wherein the age of the sludge in the second stage amounts to 5 to 30 days.
Claim 12
Dependent Claim
41 words
The method as defined in claim 10, including the step of recycling a quantity of sludge per hour which amounts to one-fifth to one-half of the volume of the settling basin of the second stage back into the aeration tank thereof.
Claim 13
Dependent Claim
34 words
The method as defined in claim 1, wherein sludge in the settling basin of the second stage is recycled back into the associated aeration tank thereof after a period of one-quarter to 4 hours.
Claim 14
Dependent Claim
45 words
The method as defined in claim 1, including the step of recirculating back into the first stage at least one-half of the purified nitrified waste water delivered to the settling basin of the second stage during a period of 24 hours from such settling basin.
Claim 15
Dependent Claim
32 words
The method as defined in claim 13, wherein approximately as much purified nitrified waste water is again delivered to the first stage as there is delivered non-purified waste water to such stage.
Claim 16
Dependent Claim
21 words
The method as defined in claim 1, including the step of maintaining the hydraulic load of the first stage approximately constant.
Claim 17
Dependent Claim
41 words
The method as defined in claim 15, wherein for the purpose of maintaining approximately constant the hydraulic load during irregular waste water infeed there is employed purified nitrified waste water from an overflow of the settling basin of the second stage.
Claim 18
Dependent Claim
43 words
The method as defined in claim 1, wherein the purified nitrified waste water recirculated back to the first stage is removed from the settling basin of the second stage at a depth of 0.2 to 2 meters below the waste water level thereof.
Claim 19
Dependent Claim
24 words
The method as defined in claim 17, wherein the said depth of removal is at approximately 0.8 meters below the waste water level thereof.
Claim 20
Dependent Claim
40 words
The method as defined in claim 1, wherein the portion of the purified nitrified waste water circulated back from the settling basin of the second stage to the first stage is introduced into the aeration tank of the first stage.
Claim 21
Dependent Claim
38 words
The method as defined in claim 1, wherein the portion of the waste water circulated back from the settling basin of the second stage into the first stage is introduced into the settling basin of the first stage.
Claim 22
Dependent Claim
44 words
The method as defined in claim 1, wherein the portion of the water circulated back from the settling basin of the second stage into the first stage is introduced into a connection between the aeration tank and the settling basin of the first stage.
Claim 23
Dependent Claim
27 words
The method as defined in claim 1, wherein for the purpose of additionally eliminating phosphates without disturbing nitrification there is added to the second stage precipitation chemicals.
Claim 24
Dependent Claim
19 words
The method as defined in claim 22, wherein the precipitation chemicals are selected from aluminum salts and iron salts.
Claim 25
Dependent Claim
31 words
The method as defined in claim 22, including the step of adding such precipitation chemicals to the waste water prior to its entry into the settling basin of the second stage.
Claim 26
Dependent Claim
21 words
The method as defined in claim 22, wherein such precipitation chemicals are added to the aeration tank of the second stage.
Claim 27
Dependent Claim
21 words
The method as defined in claim 1, wherein for improving the sedimentation properties there is added to the second stage flocculants.
Claim 28
Dependent Claim
23 words
The method as defined in claim 1, wherein for improving the sedimentation properties there is added to the second stage a precipitation agent.
Claim 29
Dependent Claim
32 words
The method as defined in claim 1, including the step of providing a BOD 5 -sludge load in the first stage ranging from 0.05 to 0.05kg BOD 5 per kg dry solids.
Claim 30
Dependent Claim
34 words
The method as defined in claim 28, including the step of continuously maintaining at least two-thirds of the quantity of sludge contained in the first stage present in the settling basin of such stage.
Claim 31
Dependent Claim
32 words
The method as defined in claim 1, including the step of providing a BOD 5 -sludge load in the second stage ranging from 0.01 to 0.3kg BOD 5 per kg dry solids.
Claim 32
Independent Claim
344 words
A method of eliminating organic and inorganic bound nitrogen from domestic and industrial waste water in a biological activated sludge sewage purification installation capable of directly processing unclarified waste water comprising two stages connected in series, each stage containing an aeration tank and a subsequently connected settling basin, wherein the waste water is aerated in the first stage and is subsequently introduced into the settling basin of the first stage where a clarified effluent is transferred into the second stage aeration tank where it is again aerated and subsequently introduced into the settling basin of the second stage, the improvement comprising the steps of: aerating influent waste water containing organic and inorganic bound nitrogen in the aerating tank of the first stage and ammonifying the organic bound nitrogen, transferring the ammonified waste water which also contains nitrates therein to the settling basin of the first step where dentrification of the nitrate occurs, said aeration step being controlled to maintain a substantially zero oxygen level in the clarified effluent leaving the first stage settling basin, transferring the clarified effluent from the settling basin of the first stage which is essentially free of oxygen and containing ammonia to the aeration tank of the second stage and aerating to an oxygen level of at least about 2mg/l to provide an aerobic condition in the second stage for nitrification of the ammonia in the waste water to nitrates, continuously recirculating a portion of the clarified effluent from the settling basin of the second stage and which contains nitrates back into the first stage, and denitrifying the recirculated portion of the waste water in the first stage where there are provided favorable conditions for the ammonification of the organic bound nitrogen and for the denitrification of the nitrate in the influent and the nitrate in the recirculated effluent, the provision of said favorable conditions including recirculating approximately as much purified nitrified waste water to the first stage as there is delivered non-purified waste water to such first stage, and maintaining approximately constant the hydraulic load of the first stage.
Claim 33
Independent Claim
344 words
A method of eliminating organic and inorganic bound nitrogen from domestic and industrial waste water in a biological activated sludge sewage purification installation capable of directly processing unclarified waste water comprising two stages connected in series, each stage containing an aeration tank and a subsequently connected settling basin, wherein the waste water is aerated in the first stage and is subsequently introduced into the settling basin of the first stage where a clarified effluent is transferred into the second stage aeration tank where it is again aerated and subsequently introduced into the settling basin of the second stage, the improvement comprising the steps of: aerating influent waste water containing organic and inorganic bound nitrogen in the aerating tank of the first stage and ammonifying the organic bound nitrogen, transferring the ammonified waste water which also contains nitrates therein to the settling basin of the first step where dentrification of the nitrate occurs, said aeration step being controlled to maintain a substantially zero oxygen level in the clarified effluent leaving the first stage settling basin, transferring the clarified effluent from the settling basin of the first stage which is essentially free of oxygen and containing ammonia to the aeration tank of the second stage and aerating to an oxygen level of at least about 2mg/l to provide an aerobic condition in the second stage for nitrification of the ammonia in the waste water to nitrates, continuously recirculating a portion of the clarified effluent from the settling basin of the second stage and which contains nitrates back into the first stage, and denitrifying the recirculated portion of the waste water in the first stage where there are provided favorable conditions for the ammonification of the organic bound nitrogen and for the denitrification of the nitrate in the influent and the nitrate in the recirculated effluent, the provision of said favorable conditions including recirculating approximately as much purified nitrified waste water to the first stage as there is delivered non-purified waste water to such first stage, and maintaining approximately constant the hydraulic load of the first stage.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-03-07 | 1980-09-06 | 1981-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-07 | 1984-09-06 | 1985-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-07 | 1988-09-06 | 1989-03-08 | $7700.00 | Window Closed / Lapsed |