Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; College of Environment and Ecology, Chongqing University, Chongqing 400045, China.
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Bioresour Technol. 2023 Jul;379:129000. doi: 10.1016/j.biortech.2023.129000. Epub 2023 Apr 1.
Constructed wetlands (CWs) amended with biochar have attracted much attention for nitrate removal treating secondary effluent. However, little is acknowledged about the linkage among the nitrate removal performance, microbial metabolic pathway of nitrate, and biochar properties. Herein, biochars pyrolyzed under 300 °C, 500 °C, and 700 °C (BC300, BC500, and BC700, respectively) were used in CWs to reveal the relationship. Results showed that CWs amended with BC300 (59.73%), BC500 (53.27%), and BC700 (49.07%) achieved higher nitrogen removal efficiency, compared with the control (39.51%). Metagenomic analysis showed that biochars could enrich the genes, which encoded key enzymes (adenosine triphosphate production, and electrons generation, transportation, and consumption) involved in carbon and nitrate metabolism. Further, biochar pyrolyzed under lower temperature, with higher oxygen content, molar O/C ratio, and the electron donating capacity, in CWs could obtain higher nitrate removal efficiency. Overall, this research offers new understandings for the promotion of denitrification in CWs amended with biochar.
人工湿地（CWs）添加生物炭后，因其在处理二级出水时具有去除硝酸盐的能力而受到广泛关注。然而，对于硝酸盐去除性能、硝酸盐微生物代谢途径和生物炭特性之间的联系，人们的了解还很有限。在此，本文分别使用在 300°C、500°C 和 700°C 下热解的生物炭（BC300、BC500 和 BC700）来研究人工湿地，以揭示它们之间的关系。结果表明，与对照（39.51%）相比，添加 BC300（59.73%）、BC500（53.27%）和 BC700（49.07%）的 CWs 具有更高的氮去除效率。宏基因组分析表明，生物炭可以富集编码参与碳和硝酸盐代谢的关键酶（三磷酸腺苷生成和电子生成、传输和消耗）的基因。此外，在 CWs 中，低温热解、含氧率较高、摩尔 O/C 比和电子供体能力较高的生物炭可以获得更高的硝酸盐去除效率。总的来说，本研究为促进 CWs 添加生物炭后的反硝化作用提供了新的认识。
