DENITRIFICATION
In denitrification, nitrates are reduced to nitrites, and then the reduction of nitrites to nitrogen gas occurs. (Reduction is the opposite of oxidation.) Reduction of nitrites is carried all the way to ammonia by a few bacteria organisms, but most of them carry the reduction to the end product of nitrogen gas, which escapes into the atmosphere. The bacteria utilize the nitrites and nitrates as the oxygen source in their life processes. This process is carried out under anoxic or near anaerobic conditions.