Enhancing completely autotrophic nitrogen removal over nitrite by trace NO₂ addition to an AUSB reactor

• Published in: Journal of chemical technology and biotechnology (1986) 2010-02, Vol.85 (2), p.204-208
• Main Authors: Zhang, Daijun, Cai, Qing, Cong, Liying
• Format: Article
• Language: English
• Subjects: Aerated; aerated upflow sludge bed reactor; aerobic ammonium oxidation; anaerobic ammonium oxidation; Applied sciences; Carbon dioxide; Chemical engineering; Exact sciences and technology; Nitrites; Nitrogen dioxide; Nitrogen removal; Oxidation; Reactors; Sludge; trace NO2 addition enhancing CANON
• ISSN: 0268-2575; 1097-4660; 1097-4660
• DOI: 10.1002/jctb.2288

BACKGROUND: Completely autotrophic nitrogen removal over nitrite (CANON) could decrease energy consumption and CO₂ release compared with conventional nitration-denitrification. Trace NO₂ addition could enhance the activities of aerobic and anaerobic ammonium oxidation.RESULTS: An aerated upflow sludge bed (AUSB) reactor inoculated simultaneously with aerobic and anaerobic ammonium oxidizing sludge was operated to cultivate granular sludge capable of carrying out CANON. The results showed that the efficiency and rate of total nitrogen (TN) removal reached 61% and 0.114 kgN, respectively (m⁻³ day⁻¹) for DO = 0.5-0.6 mg L⁻¹. Batch tests indicated that trace NO₂ addition could increase the CANON activity of sludge. The TN removal rate and efficiency of the reactor was increased to 0.234 kgN m⁻³ day⁻¹ and 63%, respectively, when the reactor was aerated with air containing 2.7-3.3 mmol m⁻³ NO₂ and DO was at 0.5-0.8 mg L⁻¹.CONCLUSIONS: Trace NO₂ addition provides an alternative to increase the capacity of a CANON system at low DO concentration. Copyright