https://scholars.lib.ntu.edu.tw/handle/123456789/449099
標題: | Flume experiments for optimizing the hydraulic performance of a deep-waterwetland utilizing emergent vegetation and obstructions | 作者: | Shang-Shu Shih Hong, Shang-Shang TSANG-JUNG CHANG |
關鍵字: | Constructed wetland; Flume experiment; Hydraulic efficiency; Reynolds number; Similarity; Tracer | 公開日期: | 2016 | 卷: | 8 | 期: | 6 | 來源出版物: | Water | 摘要: | Constructed ponds and wetlands are widely used in urban areas for stormwater management, ecological conservation, and pollution treatment. The treatment efficiency of these systems is strongly related to the hydrodynamics and hydraulic residence time. In this study, we developed a physical model and used rhodamine-WT as a tracer to conduct flume experiments. An equivalent Reynolds number was assumed, and the flume was a 1/25-scale model. Emergent obstructions (EOs), submerged obstructions (SOs), and high- and low-density emergent vegetation were placed along the sides of the flume, and 49 tracer tests were performed. We altered the density, spatial extent, aspect ratio, and configurations of the obstructions and emergent vegetation to observe changes in the hydraulic efficiency of a deep-water wetland. In the cases of low-aspect-ratio obstructions, the effects of the EOs on the hydraulic efficiency were significantly stronger than those of the SOs. In contrast, in the cases of high-aspect-ratio obstructions, the improvement effects of the EOs were weaker than those of the SOs. The high-aspect-ratio EOs altered the flow direction and constrained the water conveyance area, which apparently caused a short-circuited flow phenomenon, resulting in a decrease in hydraulic efficiency. Most cases revealed that the emergent vegetation improved the hydraulic efficiency more than the EOs. The high-density emergent vegetation (HEV) improved the hydraulic efficiency more than the low-density emergent vegetation (LEV). Three cases involving HEV, two cases involving LEV, and one case involving EOs attained a good hydraulic efficiency (λ > 0.75). To achieve greater water purification, aquatic planting in constructed wetlands should not be overly dense. The HEV configuration in case 3-1 achieved optimum hydraulic performance for compliance with applicable water treatment standards. |
URI: | https://scholars.lib.ntu.edu.tw/handle/123456789/449099 | ISSN: | 2073-4441 | DOI: | 10.3390/W8060265 | SDG/關鍵字: | Banks (bodies of water); Efficiency; Regulatory compliance; Reynolds number; Systems engineering; Vegetation; Water treatment; Wetlands; Constructed wetlands; Flume experiment; Hydraulic efficiency; Similarity; Tracer; Aspect ratio; constructed wetland; flume experiment; hydrodynamics; optimization; performance assessment; Reynolds number; tracer; vegetation cover; water pollution; water treatment |
顯示於: | 生物環境系統工程學系 |
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