Anaerobic Treatment of Nitrate

While aerobic bacteria use oxygen as their terminal electron acceptor for metabolic activity, denitrifying bacteria use NO₂ and NO₃ under anaerobic conditions. In the presence of an electron donor such as hydrogen, the net effect is the conversion of nitrate to inert nitrogen gas. Heterotrophic bacteria require organic carbon and hydrogen, while hydrogen-oxidizing denitrifying (HOD) bacteria, which are autotrophic and ubiquitous, require carbon dioxide and hydrogen.