Re-acclimation performance and microbial characteristics of a thermophilic biofilter for NOx removal from flue gas

Shihan Zhang, Han Chen, Yinfeng Xia, Jingkai Zhao, Nan Liu, Wei Li

Research output: Contribution to journalArticlepeer-review

Abstract

Currently, a novel chemical absorption-biological reduction (CABR) integrated process, employing Fe(II)EDTA as a solvent, is being under development to reduce the cost of NOx removal from flue gas. In this work, the NO removal profile, re-acclimation performance, and microbial characteristics in a thermophilic biofilter were investigated at the conditions typical to CABR process. The biofilter comprised of four layers of packing material with a surface area of 1200 m2 m−3. Experimental results revealed that the biofilter could remove 95 % of the fed NO at typical flue gas conditions. As the gas residence time varied from 90 to 15 s, the NO removal efficiency decreased from 100 to 56.5 % due to the NO mass transfer limitation. The longer period of the biofilter shutdown required more time for its re-acclimation. For example, after 8-day shutdown, the biofilter was re-acclimated in 32 h. Denaturing gradient gel electrophoresis analysis of PCR-amplified product showed that Pseudomonas, a group of denitrifier, was dominant in the biofilter. Because the Pseudomonas was abundant at the bottom layer of packed-bed, the bottom layer contributed to 60–70 % of the total NO removal. In addition, Pseudomonas gradually faded away along the gas flow path from the bottom to the top of biofilter, resulting in a significant decrease in NO removal at the other three packed-bed layers. These observed results will provide the process engineering and scale-up data with respect to the biofilter operations to help advance the CABR process to pilot-scale testing.

Original languageEnglish (US)
Pages (from-to)6879-6887
Number of pages9
JournalApplied Microbiology and Biotechnology
Volume99
Issue number16
DOIs
StatePublished - Aug 27 2015

Keywords

  • CABR
  • Flue gas
  • Microbial community
  • NO removal
  • Re-acclimation

ASJC Scopus subject areas

  • Biotechnology
  • Applied Microbiology and Biotechnology

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