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Updated: Apr 30, 2026

A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities
Published on: December 25, 2015
Anoxic phases are the main N2O contributor in partial nitritation reactors treating high nitrogen loads with
J Gabarró1, P González-Cárcamo1, M Ruscalleda1
1LEQUIA, Institute of the Environment, University of Girona, Campus Montilivi, E-17071 Girona, Catalonia, Spain.
Abstract:
Partial nitritation (PN) reactors treating complex industrial wastewater can be operated by alternating anoxic-aerobic phases to promote heterotrophic denitrification via NO2(-). However, denitrification under stringent conditions can lead to high N2O production. In this study, the suitability of including anoxic phases in a PN-SBR treating real industrial wastewater was assessed in terms of process performance and N2O production. The PN-SBR was operated successfully and, when the HCO3(-):NH4(+) molar ratio was adjusted, produced a suitable effluent for a subsequent anammox reactor. 10-20% of the total influent nitrogen was removed. N2O production accounted for 3.6% of the NLR and took place mainly during the anoxic phases (60%). Specific denitrification batch tests demonstrated that, despite the availability of biodegradable COD, NO2(-) denitrification advanced at a faster rate than N2O denitrification, causing high N2O accumulation. Thus, the inclusion of anoxic phases should be avoided in PN reactors treating industrial wastewaters with high nitrogen loads.
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