Anoxic
denitrification is an ecologically important bacterial process that converts reactive nitrogen
compounds to inert nitrogen gas. The discharge of excessive amounts of
nitrogen can result in the growth of large amounts of algae
and a zone of low dissolved oxygen (hypoxia), which can stress aquatic life in
receiving waters such as streams, lakes, bays, estuaries, etc. The
primary method of denitrification is to introduce nitrogen-eating bacteria into
the wastewater. Another method is to
introduce a neutrally buoyant media to which the bacteria anchors itself while
consuming the nitrogen.
Generically, bacteria
uses the organic carbon found in waste water as its energy source. Through
bacterial action, faculative bacteria reduce nitrates into nitrites which then
evolves into nitrogen gas which can be properly vented to the environment as an
inert (non-reactive) gas. The process is generally a closed system in that
the mixing system is designed to minimize oxygen absorption from the atmosphere.
Top entering mixers are used to maintain the activated sludge, which encourages
the right biological communities to form resulting in an anoxic condition
suitable for denitrification.
09.21.23
