# US 5,348,655 A · Method for increasing the capacity of sewage treatment plant

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- Number: US 5,348,655 A
- Document ID: US5348655A
- Status: Granted
- Kind: A
- Application number: 08/086,692
- Filed: 1993-07-02
- Granted: 1994-09-20
- Earliest claimed: 1993-07-02
- Assignees: Liquid Carbonic Corporation
- Inventors: Luis E. D. Simas; Jesus F. Gaztambide
- Web page: https://patentgrep.com/patent/US5348655A

## CPC

- C02F 3/26: using pure oxygen or oxygen-rich gas
- Y02W 10/10: Biological treatment of water, waste water, or sewage
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)
- Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT

## Abstract

The present invention is directed to a method for increasing the capacity of a sewage treatment plant. In the method, oxygen is injected into the recycle sludge stream from the settling tank prior to introducing the recycle sludge stream into the secondary waste water treatment tank.

## Claims

### Claim 1

A method for increasing the capacity of a sewage treatment plant comprising a secondary waste water treatment tank, a settling tank downstream from the secondary waste water tank and a recycle sludge line for the transmission of a recycle sludge from the settling tank to the secondary waste water treatment tank, the method comprising injecting oxygen into the recycle sludge having an oxygen level of less than about 0.5 ppm in the recycle sludge line during transmission of the recycle sludge from the settling tank, the injection made in amounts over a period of from about three to about seven days at a rate effective for bringing the oxygen level to about 2 ppm to about 5 ppm in the recycle sludge in the recycle sludge line prior to introducing said recycle sludge into the secondary waste water treatment tank, thereby increasing the capacity of the sewage treatment plant by about 30% relative to the same plant wherein oxygen is not injected into said recycle sludge line.

### Claim 2 (depends on 1)

A method in accordance with claim 1 wherein said oxygen is injected into recycle sludge in a bypass sludge line which is taken from said recycle sludge line.