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Updated: May 30, 2026
08:05
Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
Published on: October 7, 2020
Effect of pH and nitrite concentration on nitrite oxidation rate
E Jiménez1, J B Giménez, M V Ruano
1Instituto de Ingeniería del Agua y Medio Ambiente, Universidad Politécnica de Valencia, Camino de Vera s/n, 46022 Valencia, Spain. emjidou@upvnet.upv.es
Bioresource Technology
|August 17, 2011
Summary
Nitrite oxidizing bacteria (NOB) activity in activated sludge is primarily influenced by total nitrite concentration, not free nitrous acid. Low pH significantly inhibits NOB, while high pH shows no adverse effects.
Area of Science:
- Environmental microbiology
- Wastewater treatment
Background:
- Nitrite oxidizing bacteria (NOB) are crucial for nitrification in activated sludge systems.
- Understanding the factors affecting NOB activity is essential for optimizing wastewater treatment processes.
Purpose of the Study:
- To investigate the impact of pH and nitrite concentration on NOB activity.
- To determine the substrate for NOB and identify inhibitory conditions.
Main Methods:
- Laboratory batch experiments utilizing respirometric techniques.
- Measurement of bacterial activity at varying pH and total nitrite concentrations (TNO₂).
Main Results:
- Nitrite oxidation rate (NOR) is dependent on TNO₂ concentration, independent of free nitrous acid (FNA).
- NOB activity is inhibited at low pH (no activity at pH 6.5) but not at high pH (7.5-9.95).
Conclusions:
- FNA is not the primary substrate for NOB; TNO₂ concentration is the key factor.
- A kinetic model incorporating pH inhibition and TNO₂ effects was proposed, yielding kinetic and inhibition constants.
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