Probing the Stoichiometry of the Nitrification Process using the Respirometric Approach

Abstract

Quantifying oxygen demand and nitrifier yield are important in the design and operation of advanced wastewater treatment systems. However, the accurate stoichiometry of the autotrophic nitrification process has not been fully developed. in this research, stoichiometric links between nitrifier yield, ammonia and nitrite oxidization, ammonia assimilation, and oxygen uptake for each step of the nitrification process were determined. a pulse-flow respirometer was used to measure the oxygen uptake for complete nitrification and nitrite oxidation reactions. Results indicated that the specific oxygen uptake was 4.23 mg-O2/mg-N oxidized for complete nitrification, with 3.17 mg-O2/mg-N oxidized for ammonia oxidation (first step nitrification) and 1.06 mg-O2/mg-N oxidized for nitrite oxidation (second step nitrification). for the complete nitrification, fractions of ammonia used for electron donation, synthesis of ammonia oxidizers, and synthesis of nitrite oxidizers were 97.1%, 2.2%, and 0.7%, respectively. the fractions of electrons transferred into cell synthesis were approximately 7.5% for ammonia oxidation and 7.3% for nitrite oxidation. Biomass yield coefficients for ammonia oxidizers and nitrite oxidizers were 0.18 and 0.06 g-VSS/g-N oxidized, respectively. These parameters are critical when calculating oxygen needs and nitrifier biomass concentrations during the design of advanced wastewater treatment processes. © 2012 Elsevier Ltd.

Department(s)

Civil, Architectural and Environmental Engineering

Comments

Smithsonian Environmental Research Center, Grant None

Keywords and Phrases

Ammonia assimilation; Nitrification; Nitrifier yield; Oxygen uptake; Stoichiometry

International Standard Serial Number (ISSN)

1879-2448; 0043-1354

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Elsevier; IWA Publishing, All rights reserved.

Publication Date

15 Nov 2012

PubMed ID

22975736

Link to Full Text

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