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Simultaneous autotrophic denitrification and nitrification in a low-oxygen reaction environment
Journal article   Open access   Peer reviewed

Simultaneous autotrophic denitrification and nitrification in a low-oxygen reaction environment

Ganapathy Ramanathan, Christopher M Sales and Wen K Shieh
Water science and technology, v 70(4), pp 729-735
2014
PMID: 25116505
url
https://doi.org/10.2166/wst.2014.292View
Published, Version of Record (VoR)Maybe Open Access (Publisher Bronze) Open

Abstract

Ammonia - metabolism Ammonium Compounds - metabolism Bacteria - metabolism Biological Oxygen Demand Analysis Biomass Bioreactors Denitrification Nitrification Nitrites - metabolism Oxygen
The occurrence of autotrophic denitrification and nitrification activities by ammonia-oxidising bacteria and nitrite-oxidising bacteria is studied in a bioreactor system operable at low-dissolved oxygen (DO) and at variable oxygen influx rates. At a loading of 3.6 mg NH4(+)-N/h into the bioreactor, simultaneous autotrophic denitrification and nitrification contributed to NH4(+)-N removal over oxygen influxes of 2-14 mg O2/h and DO <0.5 mg/L. The maximum autotrophic denitrification (or total-N removal) rates were achieved in a narrow oxygen influx band of 3-5 mg O2/h, where it accounted for up to 36% of NH4(+)-N removal. At oxygen influx >16 mg O2/h and DO >2 mg/L, autotrophic denitrification ceases and roughly 90% of feed NH4(+)-N is oxidised to NOX(-)-N. The stability of total effluent chemical oxygen demand (COD) over the range of oxygen influxes tested confirms the absence of heterotrophic denitrification in the bioreactor. The long solids residence time of the stable biomass zone (21 days) led to production of effluent COD as a result of cell decay, and thus effluent COD was used to calculate more accurately the mean cell residence time.

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Collaboration types
Domestic collaboration
Web of Science research areas
Engineering, Environmental
Environmental Sciences
Water Resources
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