Course: BFM 203 Water Treatment and Control

Lecture

Aeration and Artificial De-stratification

Aeration and Artificial De-stratification

Aeration is the addition of air to water by passing air through water or water through air. Re-aeration is the introduction of air into the lower layers of reservoirs through use of forced air diffusers. Aeration forces vertical mixing within a lake or reservoir to eliminate separate layers of temperature, plant, or animal life. This process is referred to as de-stratification. Aeration may also be achieved by pumping water from lower levels in a reservoir and spraying the water into the air. This aeration method increases evaporation loss.

Another method of destratification include mechanical or hydraulic pumping of water from one level in a reservoir to an area of different density which causes circulation and mixing to occur. Still another option is the use of a diffused air system that uses a compressor to pump air to diffusers which release bubbles near the bottom of a reservoir. Dissolved oxygen is added to deeper waters as they rise to meet the surface and come into contact with the atmosphere. Destratification by air diffusion has the added benefit of increasing dissolved oxygen in the reservoir. Circulation mixing does not have this benefit.