Activated sludge method
US4655925A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 18, 1985 |
| Grant date | Apr 7, 1987 |
| Priority date | — |
| Expiry date | Jan 18, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S210/906
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of removing nitrogen and phosphorus from waste water by using an activated sludge including aerobic bacteria is disclosed. The waste water is fed continuously and gradually into a treatment basin in which the sludge is contained so that a mixed liquor consisting of the waste water and the sludge is formed therein. A cycle consisting of an agitating step and an aerating step is repeated at least two times and each cycle is finished within two hours, with the ratio of the agitating time to the aerating time being between one to one and to one. In the agitating step, the mixed liquor presents an anoxic condition and a succeeding anaerobic condition. Denitrification occurs in the anoxic condition and the aerobic bacteria release phosphorus in the anaerobic condition. During the aerating step, nitrification is caused while the bacteria excessively ingest phosphorus from the mixed liquor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.