Anoxic phases are the main N2O contributor in partial nitritation reactors treating high nitrogen loads with alternate aeration

Bioresour Technol. 2014 Jul:163:92-9. doi: 10.1016/j.biortech.2014.04.019. Epub 2014 Apr 16.

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.

Keywords: Anammox; Anoxic feeding; Industrial wastewater; Leachate; N(2)O.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Air*
  • Bioreactors*
  • Nitrates / metabolism*
  • Nitrous Oxide / metabolism*
  • Oxygen / metabolism*
  • Pilot Projects
  • Wastewater

Substances

  • Nitrates
  • Waste Water
  • Nitrous Oxide
  • Oxygen