By Patrick Higgins
Nitrite, long disregarded as an insignificant intermediate in the wastewater nitrification process, has recently gained prominence. Research and practice has identified nitrite as the critical variable in newly-developed treatment processes that utilize shortcuts in the nitrogen cycle to more efficiently remove nitrogen from wastewater.
The traditional process for nitrification/denitrification proceeds as follows:
1) ammonia (NH3) is oxidized to nitrite (NO2) and nitrite to nitrate (NO3) with input of oxygen
2) nitrate is reduced to nitrite and nitrite to nitrogen gas (N2) which escapes to the atmosphere with input of organic carbon and excluding oxygen.