Quantifying the Chronic Effect of Low DO on the Nitrification Process


Our previous study indicated that a low dissolved oxygen (DO) could enrich and shift nitrifier community, making complete nitrification feasible under long-term low DO conditions. This research determined nitrifier kinetic constants, and quantified the chronic effect of low DO on the overall nitrification process. For ammonia oxidizing bacteria (AOB), the half-velocity constants of DO on the growth (KDO-g) and decay (KDO-d) were 0.29 and 0.48 mgL-1, respectively. For nitrite oxidizing bacteria (NOB), those values were 0.08 and 0.69 mgL-1, respectively. The low KDO-g values for both AOB and NOB suggest that a DO of greater than 1 mgL-1 does not provide further benefit to nitrification, and the lower KDO-g value for NOB suggests that nitrite oxidation is less impacted by a low DO. The KDO-d values of 0.48 and 0.69 mgL-1 for AOB and NOB, respectively, suggest that a low DO of less than 1 mgL-1 significantly inhibits the decay of both AOB and NOB, resulting in their enrichment. The relationship between the operational DO and required SRT for complete nitrification was developed to provide a theoretical foundation for operating an advanced wastewater treatment plant under low DO, to significantly improve aeration energy efficiency.


Civil, Architectural and Environmental Engineering


This research was partially supported by a grant from the Army Research Lab (ARL) through the Leonard Wood Institute (LWI) and Frontier Environmental Technology, LLC.

Keywords and Phrases

Ammonia; Nitrite; Oxygen; Betaproteobacteria; Biochemical oxygen demand; Biomass; Chemistry; Growth; Development and aging; Nitrification; Oxidation reduction reaction; Procedures; Theoretical model; Water management; Ammonia; Betaproteobacteria; Biological Oxygen Demand Analysis; Models; Theoretical; Nitrification; Nitrites; Oxidation-Reduction; Water Purification; Half-velocity constant; Low DO aeration; Modeling; Nitrification kinetics; Nitrifier decay; Nitrifier growth

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version


File Type





© 2015 Elsevier, All rights reserved.

Publication Date

01 Dec 2015

PubMed ID