深水型人工溼地水力效率改善之研析

Hydraulic Efficiency Improvement of Deep Water Constructed Wetlands

李瑋婷(Wei-Ting Lee)

指導教授 ： 張倉榮

國立臺灣大學/生物資源暨農學院/生物環境系統工程學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.03009

摘要

近年來，汙水處理系統將人工溼地設為其淨化單元之一，故本論文針對其人工溼地處理單元做進一步的研究。表面流人工溼地之水深受限於水力效率的要求，設計上一般控制在0.15至0.8公尺間。但受限的面積及水深讓人工溼地處理的水量不足應付新的汙水之產生，同時也降低其附加的遲滯洪水功能，在溼地面積不足下，實務上僅能藉由加深人工溼地深度來增加水質及洪水的處理量，故如何在有限的面積使人工溼地加深卻又能提高其水力效率是很重要的課題。本研究發現當空池水深大於0.72公尺，溼地之水力效率即呈不佳狀態，因此，深入探討水深超過0.8公尺之深水型人工溼地，並提出有效的水力效率改善方式。
　　為有效提升深水型人工溼地之水力效率，本研究主要以增加障礙物的方式為之，並分析浸沒式與非浸沒式的改善效率差異。首先，藉由障礙物的排數與擺放方式進行改善。在相同水深下，以均勻擺放在浸沒情形與非浸沒情形及序列擺放在浸沒情形與非浸沒情形，模擬障礙物排數累加擺放之改善效率。接著，再選擇2、8及12排障礙物分別在浸沒與非浸沒情形下，模擬均勻與序列擺放時之可接受水深，並相互比較。研究結果發現，當均勻或序列擺放障礙物時，障礙物在非浸沒下所能處理的水深明顯優於浸沒情形；此外，障礙物在非浸沒情形下，均勻或序列擺放能達到可接受水力效率之水深則明顯優於浸沒情形。因此，本研究認為適當的增加「非浸沒式障礙物」有機會同時滿足高水深及高水力效率的要求。

關鍵字

人工溼地 ； 水深 ； 滯留時間分佈 ； 平均滯留時間 ； 水力效率 ； 數值試驗

並列摘要

Recently, the constructed wetland (CW) has been included one of the units in the wastewater treatment system. In this thesis, the further research for this CW unit was conducted. The water depth of free water surface CW is bounded by performance of hydraulic efficiency. The design of the CW is thus ranging from 0.15 to 0.8 meter in practice. However, it would decrease the capacity of flooding detention volume due to the restriction of serious land use and limited area. Increasing the depth of CW is one of the most effective ways to increase not only the quality of treated water but also the quantity of flood detention. Therefore, the way of improving the hydraulic efficiency of deep water is critical. The poor hydraulic efficiency appeared when the water depth is over 0.72 meter.
In this study, to improve the hydraulic efficiency of deep water CW, the placement of obstructions is adopted as the treatment. First, the improvements are conducted through the amount and the arrangement ways of the obstructions. And then, the selected cases of placing 2, 8 and 12 obstructions in submerged or emerged situation are used to tested the acceptable water depths in both uniform and sequence arrangements. The results show that when the obstructions are in either uniform or sequence way, the obstructions in the emerged condition have better improvements. Furthermore, when obstructions are under the emerged condition in either uniform or sequence arranging way, the acceptable water depth can be deeper. Thus properly increasing emerged obstructions can achieve the purposes of deep water depth and high hydraulic efficiency at the same time.

並列關鍵字

Constructed Wetland ； Water Depth ； Residence Time Distribution ； Hydraulic Efficiency ； Numerical Experiment

參考文獻

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