Updated: July 2002

1. Purpose

For deodorization of the odor which occurs from the wastewater treatment plant, the physical and chemical deodorization such as activated carbon adsorption and scrubber are used conventionally.
However, those deodorizing methods have some problems of high operation cost and so on. Kobe Steel offers "Biological Deodorization Tower" which has been developed on considering the bacterial deodorizing activity, low operation cost and easy maintenance.

2. Performance

Deodorization (Example of Analysis)

3. Characteristics

1) In the biological deodorization, the carriers to which bacteria adhere are packed in the tower and biological pile are made. The carriers are porous pellets by which the carbon is assumed to be a principal ingredient and so excellent in holding water and biomass that the equipment deodorizes the gas effectively.
2) Periodical exchange of the carriers is not required because the deodorization is conducted by the function of bacteria. Besides the structure of the equipment is simple, so the maintenance is easy.
3) Power of the fan feeding the raw gas is small because of the low pressure loss of the packed bed. Besides exchange of carries is not required, thus the operation cost can be lowered by 30-50 percent compared with conventional physical and chemical method.
4) The required space for the equipment is small because of its compactness.

4. Principle

The raw gas is deodorized while the gas flows through the biological pile in the tower. The odor is decomposed into sulfuric acid and nitric acid by bacteria. The washing water tank is arranged at the bottom of the tower, and washing water is sprinkled on the biological pile intermittently or continuously by the washing water pump and the nozzles. The sprinkling is necessary for feeding the water to bacteria multiplying and washing sulfuric acid and nitric acid out. The water is circulated after neutralization with a small amount of sodium hydroxide.

5. Figure (Schematic Flow of Deodorizing System)

6. Subject

Wastewater treatment plant
Human excreta treatment plant
Compost plant
Live-stock farm

7. Example

Japan Sewage Works Agency
Eastern Hyogo Area Wide Sludge Treatment Plant