Aerated Lagoon

An aerated lagoon consists of a large pond or tank equipped with mechanical aerators to maintain an aerobic environment. Aeration also keeps the organic materials suspended. When allowed to settle, facultative bacteria can rapidly deplete the oxygen supply in the sediment and allow anaerobic organisms to start growing. This will give rise to all the horrible smells or odours that are frequently associated with treatment lagoons.

Aerobic digestion results in complete biological oxidation leading to breakdown products with low or no odors. The breakdown in an aerated lagoon is slower than in an activated sludge system, but it allows an appropriate amount of time for the breakdown of complex materials. The microbial population is also less sensitive to changes in effluent strengths and types. The effluent from the lagoon is normally channeled to settling tanks to remove suspended solids.