How nitrate affects perchlorate reduction in a methane-based biofilm batch reactor

Pan Long Lv, Ling Dong Shi, Qiu Yi Dong, Bruce Rittmann, He Ping Zhao

Research output: Contribution to journalArticle

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Abstract

Nitrate (NO3) affected perchlorate (ClO4) reduction in a membrane batch biofilm reactor (MBBR), even though the electron donor, CH4, was available well in excess of its demand. For example, the perchlorate-reduction rate was 1.7 mmol/m2-d when perchlorate was the sole electron acceptor, but it dropped to 0.64 mmol/m2-d when nitrate also was present. The perchlorate-reduction rate returned to 1.60 mmol/m2-d after all nitrate was consumed. Denitratisoma and Azospirillum were main genera involved in perchlorate and nitrate reduction, and both could utilize NO3 and ClO4 as electron acceptors. Results of the reverse transcription-polymerase chain reaction (RT-PCR) showed that transcript abundances of nitrate reductase (narG), nitrite reductase (nirS), and perchlorate reductase (pcrA) increased when the perchlorate and nitrate concentrations were higher. Specifically, pcrA transcripts correlated to the sum of perchlorate and nitrate, rather than perchlorate individually. Analysis based on Density Functional Theory (DFT) suggests that bacteria able to utilize both acceptors, preferred NO3 over ClO4 due to nitrate reduction having lower energy barriers for proton and electron transfers.

Original languageEnglish (US)
Article number115397
JournalWater Research
Volume171
DOIs
StatePublished - Mar 15 2020

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Keywords

  • Competition
  • Membrane batch biofilm reactor
  • Nitrate
  • Perchlorate reductase
  • Reversible inhibition

ASJC Scopus subject areas

  • Ecological Modeling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

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