Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China.
Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China; Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China.
Water Res. 2024 Sep 15;262:122124. doi: 10.1016/j.watres.2024.122124. Epub 2024 Jul 21.
The inefficient nitrogen removal in constructed wetlands (CWs) can be attributed to insufficient carbon sources for low carbon-to-nitrogen (C/N) ratio wastewater. In this study, sugarcane bagasse fermentation liquid (SBFL) was used as a supplemental carbon source in intermittently aerated CWs to enhance nitrogen removal. The impact of different regulated influent C/N ratios on nitrogen removal and greenhouse gas (GHG) emissions was investigated. Results demonstrated that SBFL addition significantly enhanced the denitrification capacity, resulting in faster NO-N removal compared to sucrose. Moreover, intermittently aerated CWs significantly improved NH-N removal efficiency compared to non-aerated CWs. The highest total nitrogen removal efficiency (98.3 %) was achieved at an influent C/N ratio of 5 in intermittently aerated CWs with SBFL addition. The addition of SBFL resulted in a reduction of NO emissions by 17.8 %-43.7 % compared to sucrose. All CWs exhibited low CH emissions, with SBFL addition (0.035-0.066 mg·mh) resulting in lower emissions compared to sucrose. Additionally, higher abundance of denitrification (nirK, nirS and nosZ) genes as well as more abundant denitrifying bacteria were shown in CWs of SBFL inputs. The results of this study provide a feasible strategy for applying SBFL as a carbon source to improve nitrogen removal efficiency and mitigate GHG emissions in CWs.
人工湿地（CWs）中氮去除效率低下可归因于低碳氮比（C/N）废水的碳源不足。在本研究中，采用甘蔗渣发酵液（SBFL）作为间歇性曝气 CWs 的补充碳源，以增强氮去除效果。研究了不同调控进水 C/N 比对氮去除和温室气体（GHG）排放的影响。结果表明，SBFL 的添加显著增强了反硝化能力，与蔗糖相比，NO-N 的去除速度更快。此外，与非曝气 CWs 相比，间歇性曝气 CWs 显著提高了 NH-N 的去除效率。在添加 SBFL 的间歇性曝气 CWs 中，进水 C/N 比为 5 时，总氮去除效率最高（98.3%）。与蔗糖相比，SBFL 的添加使 NO 排放减少了 17.8%-43.7%。所有 CWs 的 CH 排放均较低，添加 SBFL（0.035-0.066 mg·mh）比添加蔗糖的排放量更低。此外，SBFL 输入的 CWs 中显示出更多的反硝化（nirK、nirS 和 nosZ）基因和更多的反硝化细菌。本研究结果为应用 SBFL 作为碳源提高 CWs 中的氮去除效率和减少 GHG 排放提供了一种可行的策略。
