The term 'anoxic' refers to the availability of nitrate and absence
of free oxygen in a reactor.
An anaerobic selector receiving nitrate operates anoxically until
nitrate is removed, and then becomes anaerobic.
O2 aerobic metabolism>200 MV
aerobicNO3
denitrification+ 200 mV anoxicSO4 sulfate reduction0 MV anaerobic SO2 methane-200 mV
anaerobic
Nitrification – NH3 oxidising bacteria: nitrosomonas (NH3 ® NO2-), nitrobacter
(NO2- ® NO3-) Denitrification
– NO3- reducing heterotrophic bacteria (Rhizobium) (NO3- ®N2) AnoxicAnaerobic means without oxygen. More specifically, it refers to occurring or
living without oxygen present; therefore, the
chemistry of the system, environment, or organism is
characterized by reductive conditions. Many organic
contaminants are degraded under anaerobic conditions by anaerobic bacteria called anaerobes.
Anaerobes
obtain oxygen from chemically bound oxygen compounds such as nitrate and sulfate. This process is called anaerobic respiration.
Facultative organisms use either free dissolved oxygen
or chemically bound oxygen.
Anoxic is an adjective that
means without oxygen. For example, anoxic ground water
is ground water that contains no dissolved oxygen.