Aeration Basins & Aerobic Digesters
An aerated lagoon or aerated basin is a holding and/or treatment pond provided with artificial aeration to promote the biological oxidation of wastewaters. These aeration basins use oxygen (or air) and microbial action to biotreat the pollutants in the wastewater.
Aerobic digesters and aeration basins are very similar. Aeration basins are generally considered to be a large, open earthen lagoon or pond.
The large surface areas involved cause more drastic temperature variations than found in aerobic digesters; thus, causing variations in sludge retention times. If solids are returned to the aeration basin process, there is no difference between an aeration basin and the activated sludge process.
Aerobic digesters are better described as a tank than as a pond. These aerobic digesters are generally constructed of concrete and are rectangular so multiple tanks can share common walls. Large tanks would have two diffusers with most plants having at least two digesters. The aerobic digestion process can be continuous or batch.