School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing 400074, China; Engineering Laboratory of Environmental Hydraulic Engineering of Chongqing Municipal Development and Reform Commission, Chongqing Jiaotong University, Chongqing 400074, China.
School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing 400074, China.
Sci Total Environ. 2022 Jun 25;827:154295. doi: 10.1016/j.scitotenv.2022.154295. Epub 2022 Mar 2.
In laboratory experiments, the nitrogen migration and transformation in the stormwater bioretention system under different dry-wet alterations were studied. The removal efficiency showed that nitrogen could be removed efficiently in bioretention system under all dry-wet alterations, and the shorter antecedent dry days (ADDs) (1-5 days) were beneficial to the removal of nitrogen before plants decay, compared to the longer ADDs (7-22 days). Using a new method combined with Hydrus-1D model, water transport was simulated and nitrogen migration in bioretention system was quantified, indicating that NH-N was mainly removed in the planting layer, and the removal of NO-N was occurred in the submerged layer. Fate experiment showed the main fate of the nitrogen was microorganisms (1-5 ADDs) and soil immobilization (7-22 ADDs). Microbial analysis showed that shorter ADDs (1-5 days) were suitable for Firmicutes growth, while Proteobacteria and Actinobacteria accounted for greater abundance under longer ADDs (7-22 days). Canonical correlation analysis (CCA) revealed the relationships between microbial community and environmental factors. Soil moisture content, soil organic matter (SOM), TN (water), root length, and NO-N (water) were significantly correlated with bacterial community. This work may give new insights into nitrogen migration and transformation, and can provide a reference for the further mechanism study and construction of stormwater bioretention systems.
在实验室实验中，研究了不同干湿交替条件下雨水生物滞留系统中氮的迁移转化。去除效率表明，氮可以在所有干湿交替条件下的生物滞留系统中得到有效去除，并且与较长的前期干燥天数（ADDs）（7-22 天）相比，较短的前期干燥天数（1-5 天）有利于植物腐烂前氮的去除。利用Hydrus-1D 模型模拟水的运移并量化生物滞留系统中的氮迁移，结果表明 NH-N 主要在种植层中去除，而 NO-N 的去除发生在淹没层。归宿实验表明，氮的主要归宿是微生物（1-5 ADDs）和土壤固定（7-22 ADDs）。微生物分析表明，较短的 ADDs（1-5 天）有利于厚壁菌门的生长，而较长的 ADDs（7-22 天）下变形菌门和放线菌门的丰度更大。典范对应分析（CCA）揭示了微生物群落与环境因素之间的关系。土壤水分含量、土壤有机质（SOM）、TN（水）、根长和 NO-N（水）与细菌群落显著相关。这项工作可能为氮的迁移转化提供新的见解，并为进一步研究雨水生物滞留系统的机制和建设提供参考。
