Coupling anammox and heterotrophic denitrification activity at mainstream conditions in a single reactor unit

Xènia Juan-Díaz, Lluc Olmo, Julio Pérez*, Julián Carrera

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

3 Citations (Scopus)

Abstract

Mainstream partial nitritation/anammox (PN/AMX) has attracted large attention in the last decade. Two-stage configurations have been pointed out as an appealing technology for the application of the PN/AMX process at mainstream conditions. However, the process requires of an efficiency improvement by designing a new technology to remove the nitrate produced by anammox bacteria. A new reactor configuration was developed by coupling anammox to heterotrophic denitrification in a single reactor unit while avoiding competition between both processes. The addition of acetate as an external C–source allowed the removal of nitrate by heterotrophic microorganisms without hampering the anammox process by maintaining high nitrogen removal rates (0.16 ± 0.03 g N L–1 d–1) and nitrogen removal efficiencies (91 ± 8 %) (on average from acetate addition periods). Further, a proper organic load management showed to be effective to face the drawbacks derived from previous mainstream treatment stages (i.e. undesired nitrate production), without compromising effluent COD concentrations. By withdrawing samples along the sludge bed, nitrogen compounds and COD concentrations were determined at different reactor heights. This set of experimental data demonstrated that the combination of anammox and heterotrophic denitrification in a single reactor unit was possible as anammox activity dominated within bottom sludge bed sections, while heterotrophic denitrification occurred within middle and upper sludge sections. Microbial diversity results of 16S rRNA gene-targeted sequencing analyses confirmed that anammox and heterotrophic denitrifiers communities occupied two differentiated sludge bed sections along the reactor being dominated by Candidatus Brocadia (30 %) and Thauera (33 to 46 %), respectively. When heterotrophic denitrification occurred, the average N2O emissions with COD addition was ca. 50 % lower than that in periods without COD addition.

Original languageEnglish
Article number134087
Number of pages11
JournalChemical Engineering Journal
Volume431
DOIs
Publication statusPublished - 1 Dec 2021

Keywords

  • Cooperation network
  • Effluent quality
  • Heterotrophic denitrification
  • Mainstream anammox
  • Organic carbon
  • Single reactor unit
  • GRANULAR SLUDGE
  • ORGANIC-MATTER
  • PARTIAL NITRITATION
  • NITROGEN REMOVAL
  • LOW-TEMPERATURE
  • STRENGTH WASTE-WATER
  • MICROBIAL COMMUNITIES
  • SEQUENCING BATCH REACTOR
  • EMISSION

Fingerprint

Dive into the research topics of 'Coupling anammox and heterotrophic denitrification activity at mainstream conditions in a single reactor unit'. Together they form a unique fingerprint.

Cite this