Heterotrophic nitrification and aerobic denitrification (HNAD) microorganisms can accomplish simultaneous nitrification and denitrification in a single reactor, which significantly reduces area occupation and cost of construction compared to traditional autotrophic nitrification and anaerobic denitrification microorganisms. HNAD microorganisms were isolated from various habitats. Nitrogen removal of HNAD microorganisms was mainly through assimilation and dissimilation. The impacts of the initial ammonium concentration, carbon supply, C/N ratio, temperature, pH, dissolved oxygen (DO), and salin...
