WASTEWATER
By Rick LallishWhat is the most common type of lagoon currently in use to treat municipal wastewater?A. AnaerobicB. AeratedC. PolishingD. FacultativeAnswer: D. The most common lagoon treatment system in use today is the facultative lagoon. These lagoons are typically 3 to 8 feet deep. They have dual layers: an aerobic layer on top and an anaerobic layer below. The algae in the aerobic layer supply the dissolved oxygen. Light penetration determines the aerobic layer’s depth. The waste byproducts from the aerobic layer trickle down to the anaerobic layer, where digestion takes place. The two layers supplement each other. Controlled discharges of these lagoons may provide detention
