Enhancement of denitrification in biofilters by immobilized biochar under low-temperature stress

[Display omitted] •Immobilized biochar promoted denitrification in biofilters under low temperature.•Immobilized biochar inhibited toxic NO2- accumulation and N2O emissions.•HK, PFK, and PK activities in glycolysis were enhanced with immobilized biochar.•Immobilized biochar improved the electron tra...

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Published in:Bioresource technology 2022-03, Vol.347, p.126664-126664, Article 126664
Main Authors: Guo, Fucheng, Xu, Fei, Cai, Ran, Li, Dexiang, Xu, Qinyuan, Yang, Xiangyu, Wu, Zhengsong, Wang, Yubo, He, Qiang, Ao, Lianggen, Vymazal, Jan, Chen, Yi
Format: Article
Language:English
Subjects:
Biofilter
Charcoal
Denitrification
Enzyme activity
Immobilized biochar
Low temperature
Microbial community
Nitrogen
Nitrous Oxide
Temperature
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Summary:[Display omitted] •Immobilized biochar promoted denitrification in biofilters under low temperature.•Immobilized biochar inhibited toxic NO2- accumulation and N2O emissions.•HK, PFK, and PK activities in glycolysis were enhanced with immobilized biochar.•Immobilized biochar improved the electron transport system activity.•NAR, NIR, and NOS activities were significantly increased with immobilized biochar. Efficient removal of nitrate under low temperature is challenging because of the reduction of the microbial activity. This study successfully explored the promotion on the performance of denitrification utilizing the immobilized biochar in biofilters under low temperature (6 ± 2 °C). The results showed that the immobilized biochar increased the denitrification rate by 76.8% and decreased the nitrous oxide emissions by 82.5%. Mechanistic studies revealed that the immobilized biochar increased the activities of the denitrifying enzymes and three enzymes involved in glycolysis. Furthermore, the immobilized biochar elevated the activity of the electron transport system by 31.8%. Finally, structural equation model explained that the increase of nitrate reductase activity was a crucial factor to enhance the total nitrogen removal efficiency in biofilters with immobilized biochar. Overall, the use of immobilized biochar can be a novel strategy to enhance nitrogen removal and reduce greenhouse gas emissions in biofilters under low temperature.
ISSN:0960-8524
1873-2976
DOI:10.1016/j.biortech.2021.126664