2. Aeration and mixing of biological purification basins

Aeration systems installed in biological treatment tanks have a dual purpose:

• provide aerobic micro-organisms with the oxygen they need, usually borrowed from the air;

• provide sufficient homogenization and mixing to ensure renewed contact between the living environment, the pollutants and the oxygenated water.

In most cases, these systems consist of a single device or a set of devices placed in a tank of a given volume and shape to perform both functions.