The impact of external plant carbon sources on nitrogen removal and microbial community structure in vertical flow constructed wetlands

Frontiers in Environmental Science

Environmental Science

Yan Lin¹  Xiaoyu Ding¹  Xingshun Lu¹  Hang Lv¹  Manping Zhao¹  Lixin Wang²  Linhui Wu² 

[1] School of Ecology and Environment, Inner Mongolia University, Hohhot, China;School of Ecology and Environment, Inner Mongolia University, Hohhot, China;Inner Mongolia Key Laboratory of Environmental Pollution Prevention and Waste Resource Recycle, Hohhot, China;Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolia Plateau, Hohhot, China;

关键词: vertical flow constructed wetland;    plant carbon source;    nitrogen removal;    influent C/N ratio;    microbiological mechanisms;   

DOI  :  10.3389/fenvs.2023.1233422

 received in 2023-06-05, accepted in 2023-09-15,  发布年份 2023

来源: Frontiers

【 摘 要 】

The present study was developed to explore nitrogen removal performance and associated microbial mechanisms of action in vertical flow constructed wetlands (VFCWs) when using external carbon sources. These analyses ultimately revealed that alkali-soaked Phragmites australis (P. australis) could serve as an effective plant carbon source, exhibiting the lower levels of total nitrogen (TN) release and the highest chemical oxygen demand (COD) of all tested carbon sources. Nitrogen removal efficiency improved following the addition of plant carbon sources, and under carbon/nitrogen (C/N) rations of 2, 4, 5, and 7, the VFCW system was able to remove 43.69%–75.76% TN, with the highest removal rate being observed at a C/N of 5. The abundance of denitrifying microorganisms such as Thiobaillus and Halomonas were also more enriched in VFCW1 than VFCW0, with stronger correlations in the microbial network community. A qPCR approach was used to analyze functional genes involved in denitrification, revealing that the addition of plant carbon sources was associated with increases in total gene abundance and the abundance of the denitrifying gene nirS, whereas no corresponding increase in amoA or nxrA abundance was observed. Higher total gene, amoA, and nxrA abundance were observed in the upper levels of these VFCW systems as compared to the lower layers, whereas nirS exhibited the opposite abundance pattern. Overall, these findings suggested that short-range denitrification is likely to be the primary denitrification process active in this VFCW system.

【 授权许可】

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Copyright © 2023 Lin, Lu, Zhao, Ding, Lv, Wang and Wu.