Hydraulic Efficiency Calculation and Related Flow Pattern Configuration of Vegetated Deep Constructed Wetlands

• Main Authors: Shang- Shang Hong, 洪上尚
• Other Authors: Ming-Hsi Hsu
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/17024898425126436606

碩士 === 國立臺灣大學 === 生物環境系統工程學研究所 === 103 === Recently, the constructed wetland (CW) often used in sewage treatment. Artificailly constructed wetlands offer a low-cost treatment to remove some pollutants found in effluent water from industry, agriculture, and urban areas. The treatment efficiency strongly depends on flow pattern and residence times of the flow condition. This study thus presents a laboratory tracer experiment to estimate wetland residence time distributions and hydraulic efficiency, and use rhodamine-WT as the tracer. In order to improve hydraulic efficiency, 53 experiments are designed to test the improvement efficiency with different number, length and allocation of obstructions by laboratory model experiment. To improve the hydraulic efficiency of deep water constructed wetland, this study changes the obstruction placed in the direction, the number and length, and analyze the improvement of hydraulic efficiency from emergent obstructions, submerged obstructions and different density emergent vegetation on submerged obstructions. In accordance with the obstruction placed in a different direction, number and length ,12 allocations are designed. First, at the same depth and flow, compare the improvement of hydraulic efficiency between emergent obstructions and submerged obstructions. The results show that, without short-circuit current situation, the emergent obstructions of improving hydraulic efficiency is better than submerged obstructions. To enhance the hydraulic efficiency improvement of submerged obstructions, set emergent vegetationnt on submerged obstructions. Results show that the hydraulic efficiency improvement effect of high-density emergent vegetation on submerged obstructions are superior to low-density emergent vegetation on submerged obstructions. In some cases, hydraulic efficiency improvement effect of high-density emergent vegetation on submerged obstructions will be better than emergent obstructions. This study compared the emergent obstacles, submerged obstructions, high and low density emergent vegetation on submerged obstructions, to find better ways to improve the hydraulic efficiency in different allocations.