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Biogas Emission from an Anaerobic Reactor

Category: Biogas Emission

Volume: 18 | Issue: 6 | Pages: 1493-1502
DOI: 10.4209/aaqr.2018.05.0169
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Yu-Bo Zhang1,2, Yu-Long Wang1, Wei-Hua Li2, Li-Ning Bao2, Li-Han Wang2, Xian-Huai Huang 2, Bo Huang 1

  • 1 Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei 230036, China
  • 2 Anhui Provincial Key Laboratory of Pollution Control and Resource Reuse, School of Environment and Energy Engineering, Anhui Jianzhu University, Hefei 230022, China

Highlights

In UASB, nitrogen gas increased rapidly with Fe(II) addition.
Paludibacter may play crucial roles in nitrification.
Probably, Zoogloea contribute to NO3 reduction coupled to Fe(II) oxidation.
Fluviicola/Methylotenera may conduct NO2 reduction together with Fe(II) oxidation.


Abstract

Anaerobic denitrification is accompanied by biogas emissions, which may orient greenhouse gases or air pollutants. Ferrous iron play an important role in wastewater treatment. However, the effect of ferrous ion on biogas emission and the relationship between microbial community and nitrogen removal performance are not fully understood, especially in up-flow anaerobic sludge blanket (UASB) reactors. Here, the results revealed that nitrogen gas increased rapidly with Fe(II) addition. And ferrous ions enhanced denitrification and COD removal efficiency with more than 60% and 10%, respectively. Moreover, Ferrous ions addition evidently increased Hydrogenophaga, Methylotenera, Zoogloea and Fluviicola during the whole UASB reactor operation progress. The correlation coefficient analysis further confirmed that Fe(II) was positively correlated with the abundances of Hydrogenophaga, Methylotenera and Fluviicola. Based on these results of chemicals transformation kinetics, microbial community and the correlations coefficient analysis, a hypothetical mechanism is proposed: In the UASB system with Fe(II) and NH4+, firstly Paludibacter made a contribution to NH4+ oxidation and generated NO3, and then Hydrogenophaga, played an important role in NO3 reduction, Zoogloea coupled NO3 reduction to Fe(II) oxidation, Fluviicola combined with Methylotenera conducted NO2 reduction together with Fe(II) oxidation. This study will improve our understanding of ferrous ion’s influence on biogas emission, denitrification process and corresponding microbial community.

Keywords

Biogas emission Nitrogen gas Ferrous iron Denitrification Anaerobic reactors

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