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Denitrification is commonly used to remove nitrogen from sewage and municipal wastewater. It is also an instrumental process in constructed wetlands [ 28 ] and riparian zones [ 29 ] for the prevention of groundwater pollution with nitrate resulting from excessive agricultural or residential fertilizer usage. [ 30 ]
Denitrifying bacteria use denitrification to generate ATP. [5] The most common denitrification process is outlined below, with the nitrogen oxides being converted back to gaseous nitrogen: 2 NO 3 − + 10 e − + 12 H + → N 2 + 6 H 2 O. The result is one molecule of nitrogen and six molecules of water.
Dissimilatory nitrate reduction to ammonium is a two step process, reducing NO 3 − to NO 2 − then NO 2 − to NH 4 +, though the reaction may begin with NO 2 − directly. [1] Each step is mediated by a different enzyme, the first step of dissimilatory nitrate reduction to ammonium is usually mediated by a periplasmic nitrate reductase.
Aerobic denitrification, or co-respiration, the simultaneous use of both oxygen (O 2) and nitrate (NO − 3) as oxidizing agents, performed by various genera of microorganisms. [1] This process differs from anaerobic denitrification not only in its insensitivity to the presence of oxygen, but also in its higher potential to form nitrous oxide ...
One process utilizes fast growing nitrifiers utilizing nitrification of ammonia to nitrite and Anammox which is the denitrification of nitrite to atmospheric nitrogen using ammonia as an electron donor. The combination of the two processes allows for a more efficient conversion of ammonia and prevents a buildup of nitrate in the water.
Nitrite produced in the first step of autotrophic nitrification is oxidized to nitrate by nitrite oxidoreductase (NXR) . It is a membrane-associated iron-sulfur molybdo protein and is part of an electron transfer chain which channels electrons from nitrite to molecular oxygen.
Many facultative anaerobes use denitrification because nitrate, like oxygen, has a high reduction potential. Many denitrifying bacteria can also use ferric iron (Fe 3+) and some organic electron acceptors. Denitrification involves the stepwise reduction of nitrate to nitrite (NO − 2), nitric oxide (NO), nitrous oxide (N 2 O), and dinitrogen (N
Nitrogenous dissolved solids (amino acids, ammonia, etc.) are similarly converted to biological floc or oxidized by the floc to nitrites, nitrates, and, in some processes, to nitrogen gas through denitrification. While denitrification is encouraged in some treatment processes, denitrification often impairs the settling of the floc causing poor ...