Changes

Facultative waste stabilization ponds, sometimes referred to as lagoons or ponds, are frequently used to treat municipal and industrial wastewater. These earthen lagoons are usually 1.2 to 2.4 m (4 to 8 feet) in depth and are not mechanically mixed or aerated. The layer of water near the surface contains dissolved oxygen due to atmospheric reaeration and algal respiration, a condition that supports aerobic and facultative organisms. The bottom layer of the lagoon includes sludge deposits and supports anaerobic organisms. The intermediate anoxic layer, termed the facultative zone, ranges from aerobic near the top to anaerobic at the bottom.

=== Aerated Lagoons ===

[[File:Aeratedlagoons.png|thumb|right|200px|An aerated lagoon]]

In aerated lagoons, oxygen is supplied mainly through mechanical or diffused aeration rather than by algal photosynthesis. Aerated lagoons typically are classified by the amount of mixing provided. A partial mix system provides only enough aeration to satisfy the oxygen requirements of the system and does not provide energy to keep all total suspended solids in suspension.

=== Aerobic Lagoons ===

[[File:Aerobiclagoons.png|thumb|right|200px|Diagram of aerated lagoons]]

For more information: [http://aces.nmsu.edu/pubs/_m/M-106.pdf Safe Use of Household Greywater]

=== Innovative Lagoons ===

[[File:Innovativelagoons.png|thumb|right|200px|Satellite Image of an innovative lagoon]]