US4098689A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of treating waste water with activated sludge
Assignee: Idemitsu Kosan Co Ltd
•
Filing: 1976-10-04
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Granted: 1978-07-04
•
Expires: 1996-10-04
Abstract
Abstract On treating a waste water with activated sludge, an appropriate amount of sea water is added to the waste water.
Inventors
- 👤 Yasushi Kobayashi
- 👤 Minoru Iwata
- 👤 Sadao Yoshida
- 👤 Hisashi Akatsuka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 08:02
CPC Classifications
C; C02; C02F; C02F3/00; C02F3/02; Y; Y02; Y02W; Y02W10/00; Y02W10/10
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
132 words
In a method for treating an oil-containing waste water with an activated sludge in an aeration tank, wherein the waste water is passed into the aeration tank at a rate of from about 50 to about 140 m 3 /hr. per 1000 m 3 of the capacity of the aeration tank and wherein the concentration of the activated sludge in the aeration tank is from about 1000 to 8000 ppm, followed by sedimentation of the waste water and the activated sludge in a settling tank, the improvement which comprises adding to said waste water a treating agent consisting of a sea water to maintain therein a salt concentration (calculated as NaCl) of from about 0.3 to about 0.5 weight percent, to accelerate sludge sedimentation rate and to improve BOD and COD removal.
Claim 2
Dependent Claim
132 words
In a method for treating an oil-containing waste water with an activated sludge in an aeration tank, wherein the waste water is passed into the aeration tank at a rate of from about 50 to about 140 m 3 /hr. per 1000 m 3 of the capacity of the aeration tank and wherein the concentration of the activated sludge in the aeration tank is from about 1000 to 8000 ppm, followed by sedimentation of the waste water and the activated sludge in a settling tank, the improvement which comprises adding to said waste water a treating agent consisting of a sea water to maintain therein a salt concentration (calculated as NaCl) of from about 0.3 to about 0.5 weight percent, to accelerate sludge sedimentation rate and to improve BOD and COD removal.
Claim 3
Dependent Claim
75 words
The method of claim 1, wherein the sea water is added continuously to said waste water to maintain said salt concentration and regulating the addition of the sea water by decreasing the said addition when removal rate of biological oxygen demand in the treated water decreases and by increasing the said addition when the salt concentration in the waste water is up to one-half of the salt concentration at a steady state of the treatment.
Claim 4
Dependent Claim
25 words
The method of claim 1, wherein the sea water is added to the waste water before the waste water is passed to the aeration tank.
Claim 5
Dependent Claim
25 words
The method of claim 1, wherein the sea water is added to the waste water as the waste water is passed to the aeration tank.
Claim 6
Dependent Claim
15 words
The method of claim 1, wherein the sea water is added to the aeration tank.
Claim 7
Dependent Claim
12 words
The method of claim 1, wherein the sea water is added continuously.
Claim 8
Dependent Claim
16 words
The method of claim 1, wherein substantially equal amounts of the sea water are added intermittently.
Claim 9
Dependent Claim
15 words
The method of claim 1, wherein varying amounts of the sea water are added intermittently.
References Cited (Backward Citations)
US191853A
Cited
US3152983A
Cited
US3423309A
Cited
US3480144A
Cited
US3801499A
Cited
US3915853A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-07-03 | 1982-01-02 | 1982-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-03 | 1986-01-02 | 1986-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-03 | 1990-01-02 | 1990-07-04 | $7700.00 | Window Closed / Lapsed |