ABSTRACT
The term lagoon refers to a diverse array of suspended growth biochemical operations with the common characteristic that they do not include downstream clarifiers and associated settled solids recycle. Their name comes from the technique historically used to construct them, as in-ground earthen basins that resemble shallow ponds. Lagoons are typically used to stabilize biodegradable organic matter, although nitrogen removal (by nitrification/denitrification and ammonia stripping) and phosphorus removal (by chemical precipitation) are observed in some instances. Several process options are available, depending on the type of metabolism occurring and the mechanism used to provide the terminal electron acceptor. This chapter provides an overview of lagoon options, with particular focus on aerobic lagoons.
