埤塘型濕地之追蹤劑試驗及水力效率改善研究

Tracer test and hydraulic efficiency improvement of farm-pond wetlands

曾芸琦(Yun-Qi Zeng)

指導教授 ： 李鴻源

國立臺灣大學/工學院/土木工程學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.01954

摘要

近年來，人工溼地常應用於處理點源和非點源汙染，而處理汙染物的效率與溼地內的流況以及停留時間有相當程度的關聯，因此本研究應用追蹤劑試驗以評估濕地之停留時間分布以及水力效率。
本研究結合現地試驗及數值模式以探討濕地內水理特性，選用二維水理模式TABS-2模擬追蹤劑試驗，以追蹤劑試驗結果率定渦流黏滯係數、擴散係數及衰減係數，期許能更貼近真實的情況，並藉由數值模型設計不同的案例，達到改善水力效率之目的。
本研究選用Rhod-WT作為追蹤劑，於桃園傳貴池進行追蹤劑試驗，總共進行三場追蹤劑試驗，從追蹤劑試驗的結果可以發現，現地的水力效率約為0.02-0.18，顯示現地的水力特性不佳。為了改善水力效率，考慮不同的水深、流量、出入流口設置以及阻擋結構物的配置，共設計了53組數值試驗。
數值試驗的結果顯示，濕地的水深、流量與水力效率皆有高度的相關性，而於本案例中阻擋結構物的設置為有效提升水力效率的關鍵，設置單個阻擋結構物可將水力效率提升至0.68，設置兩個阻擋結構物可將水力效率提升至1.05，本研究並綜合22組數值試驗結果，發現流量與水力效率成正相關線性關係、水深與水力效率成負相關線性關係，而阻擋結構數長、寬及數量與水力效率之多變量複迴歸關係則發現，影響程度以阻擋構造物的數量最高、寬度次之、長度再次之，彼此間相差一個數量級序（order of magnitude）。

關鍵字

人工溼地 ； 水力效率 ； 數值試驗 ； 追蹤劑試驗 ； 停留時間分佈

並列摘要

Wetlands provide considerable benefits and promote biodiversity by offering habitat for water loving plants, birds and insects. Among various types of wetlands, free water surface constructed wetlands (CWs) are artificial wetlands designed to provide multiple functions, such as waste water treatment, ecosystem services, carbon reservoirs, and flood detention. CWs have been proposed as a cost-effective treatment for point and non-point source pollution in recent years. The treatment efficiency strongly depends on flow pattern and residence times of the flow condition. The treatment efficiency of CWs cannot be determined without understanding the flow dynamics of individual parcels of water through the wetland. This study thus presents a tracer experiment to estimate wetland residence time distributions and hydraulic efficiency. Both field investigation and numerical model experiment were conducted and examined. A horizontal two dimensional model, TABS-2, is employed to simulate the tracer tests. Then, varied of numerical experiments designed to achieve improve situ hydraulic efficiency.
The Chuangui pond in Taoyuan County was selected as field site, and use rhodamine-WT as the tracer to perform tracer tests to discuss residence time distribution of the constructed wetland. Three tracer tests are investigated on a 0.35 ha treatment wetland. The overall hydraulic efficient is calculated as 0.02-0.18 and reveals a poor hydraulic status. The results also indicate the worst hydraulic efficiency occurs at the deep water pond area. In order to improve hydraulic efficiency, 53 scenarios are designed to test the improvement efficiency with different water depths, flow discharge, configuration of inlet and outlet, and number and allocation of obstructions by using TABS-2 simulation. The results show that there is a high correlation between the water depth, flow and hydraulic efficiency. In this case, setting of obstruction is the key to effectively enhance hydraulic efficiency. In the case of set one obstruction, hydraulic efficiency can be raised to 0.68. In the other case of installing two obstructions, hydraulic efficiency can be raised to 1.05 which achieves a good hydraulic condition.

並列關鍵字

Constructed Wetlands ； Hydraulic Efficiency ； TABS-2 ； Numerical Experiment ； Tracer Test ； Residence Time Distribution

參考文獻

26. 王興睿，石栢岡，張文亮，2011，應用追蹤劑試驗於牡蠣殼礫間接觸水質淨化系統之人工濕地設計與延散效應分析，農業工程學報，頁17-31。

28. 郭品含，2008，水質處理型滯洪溼地之最佳化設計研究，台灣大學土木所碩士論文。

30. 張翊峰、王書斌、荊樹人、林瑩峰、李得元，2005，台灣地區人工溼地技術關聯資料庫之建立與研究，嘉南學報，第三十一期，頁253-263。

32. 錢紀銘、林健榮、張翊峰、林俊廷、吳潁祥、呂建樟、張齊升，2005，以鹽度追踪劑試驗探討小型組合式人工溼地之水力特性，嘉南學報，第三十一期，頁242-252。

35. 蘇宗敏，2007，表面流人工溼地水力效率之研究，台灣大學土木所碩士論文。