Autotrophic Nitrogen Removal in a Membrane-Aerated Biofilm Reactor Under Continuous Aeration: A Demonstration

Kevin R. Gilmore, Akihiko Terada, Barth F. Smets, Nancy G. Love, Jay L. Garland

Research output: Contribution to journalJournal articleResearchpeer-review


This work describes the successful coupling of partial nitrification (nitritation) and anaerobic ammonium oxidation in a membrane-aerated biofilm reactor (MABR) with continuous aeration. Controlling the relative surface loadings of oxygen versus ammonium prevented complete nitrite oxidation and allowed anaerobic ammonium-oxidizing bacteria (AnaerAOB) to develop and be retained for > 250 days. Daily autotrophic nitrogen removal of 1.7 g N/m(2) (75% of influent N load) was achieved at an oxygen/nitrogen surface loading ratio of 2.2, with up to 85% of the influent N proceeding through AnaerAOB. During early nitritation, nitrogen oxide (NO(g), NO2(g), and N2O(g)) emissions comprised up to 10% of the removed influent nitrogen, but emissions disappeared after proliferation of AnaerAOB. Microbial communities were radially stratified, with aerobic ammonium-oxidizing bacteria (AerAOB) colonizing nearest to and AnaerAOB furthest from the membrane. Despite the presence of nitrite-oxidizing bacteria, this work demonstrated that these autotrophic processes can be successfully coupled in an MABR with continuous aeration, achieving the benefits of competitive specific N removal rates and the elimination of gaseous nitrogen oxide emissions.
Original languageEnglish
JournalEnvironmental Engineering Science
Issue number1
Pages (from-to)38-45
Publication statusPublished - 2013


  • autotrophic process
  • continuous aeration
  • microbial community
  • Microorganisms (Bacteria, Eubacteria, Microorganisms) - Bacteria [05000] bacteria common bioindicator
  • ammonium 14798-03-9 oxidation
  • nitric oxide 10102-43-9
  • nitrite 14797-65-0 oxidation
  • nitrogen 7727-37-9 pollutant, water pollutant removal
  • nitrogen dioxide 10102-44-0
  • nitrogen oxide 11104-93-1
  • nitrous oxide 10024-97-2
  • oxygen 7782-44-7
  • 10060, Biochemistry studies - General
  • 31000, Physiology and biochemistry of bacteria
  • 37015, Public health - Air, water and soil pollution
  • 39008, Food microbiology - General and miscellaneous
  • membrane-aerated biofilm reactor MABR laboratory equipment
  • Bioprocess Engineering
  • Equipment Apparatus Devices and Instrumentation
  • Pollution Assessment Control and Management

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