Synergistic Inorganic Carbon and Denitrification Genes Contributed to Nitrite Accumulation in a Hydrogen-Based Membrane Biofilm Reactor

Si Pang, Bruce E. Rittmann, Chengyang Wu, Lin Yang, Jingzhou Zhou, Siqing Xia

Research output: Contribution to journalArticlepeer-review

Abstract

Partial denitrification, the termination of NO3-N reduction at nitrite (NO2-N), has received growing interest for treating wastewaters with high ammonium concentrations, because it can be coupled to anammox for total-nitrogen removal. NO2 accumulation in the hydrogen (H2)-based membrane biofilm reactor (MBfR) has rarely been studied, and the mechanisms behind its accumulation have not been defined. This study aimed at achieving the partial denitrification with H2-based autotrophic reducing bacteria in a MBfR. Results showed that by increasing the NO3 loading, increasing the pH, and decreasing the inorganic-carbon concentration, a nitrite transformation rate higher than 68% was achieved. Community analysis indicated that Thauera and Azoarcus became the dominant genera when partial denitrification was occurring. Functional genes abundances proved that partial denitrification to accumulate NO2 was correlated to increases of gene for the form I RuBisCo enzyme (cbbL). This study confirmed the feasibility of autotrophic partial denitrification formed in the MBfR, and revealed the inorganic carbon mechanism in MBfR denitrification.

Original languageEnglish (US)
Article number222
JournalBioengineering
Volume9
Issue number5
DOIs
StatePublished - May 2022

Keywords

  • autotrophic partial denitrification
  • denitrification genes
  • inorganic carbon fixing genes
  • membrane biofilm reactor
  • microbial community
  • nitrite accumulation

ASJC Scopus subject areas

  • Bioengineering

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