Updated: July 2002

1. Outline

The aerobic filtration process is a method of filtering by descending by descending flow under aeration, as shown in Fig.1. This method is carried out by filtering and biochemically treat an object through a column filled with a filtration medium having a relatively large particle size of 3 to 5 mm that is down flow with under aeration. And the filtration layer is automatically washed with air and water with the sequence control when the filtration layer clogs.

2. Features

It has the following features based on its characteristics.
1) As it has a large surface area, a large load can be processed (up to 4 times of a usual active sludge treatment). And as it can remove SS, it requires no sedimentation tank. Thus, it can be compact.
2) As it is constituted by a combination of physical filtration and biomembrane treatment with a very high biocontent, stable treatment can be performed even if the load greatly fluctuates, easing operation control.
3) As the aeration air bubbles go up through the gaps in the packed material, it has a high oxygen dissolution efficiency and thus requires very little air volume to give very high energy efficiency.
4) As it is based on the biomembrane process and has a high filtering function, it is especially suitable as a high grade treatment method.

3. Processing Suitable for Biomembrane Method

The following cases are particularly suitable for the present method.
- When the load fluctuation is especially large.
- Treatment of organic wastewater which tends to cause bulking.
- When high grade treatment is required.

Fig.1 Principle of the Aerobic filtration process