| 摘要: | 近年來因全球氣候異常，導致台灣產生非澇既旱之極端氣候現象頻率增加，這也導致台灣水資源的保育管理，成為水資源永續發展中不可或缺的一環。地下水為人類主要之淡水來源，但民生與農業廢水、工業生產、運送或儲存造成化學物質滲漏至地下，都可能會造成地下水污染，其中又以有機氯化物為最為常見的污染物。目前傳統的污水處理技術相當耗費能源，並且技術需求層次較高，因此在這水資源匱乏又飽受污染的當下，利用低成本、低耗能並且無二次污染的人工溼地，處理含有機氯化物的地下水，不但能美化環境，尚可達到節能減碳之目標。
本研究藉由設置試驗規模的SSF人工溼地槽體，分析以人工溼地的生態工法，應用於處理受污染地下水的可能性，並探討以下課題：(1) 含揮發性有機物污染水質特性探討；(2) 比較不同類型人工溼地系統處理受污染地下水的能力；(3) 比較傳統技術與自然淨化技術能源耗費成本；(4) 綜合以上結果所獲得之參數，評估以人工溼地系統處理受污染地下水所需的成本。
試驗規模溼地槽體為填充天然礫石、廢棄水泥塊與人造材料拉西環等三種不同介質的SSF人工溼地系統，直接處理含揮發性有機物污染之地下水。實驗結果顯示，填充天然礫石SSF人工溼地系統，對於氯乙烯的去除率為 70.30 %，1,1-二氯乙烯去除率為 83.80 %、反 1,2-二氯乙烯為 53.94 %、順 1,2-二氯乙烯為 47.38 %、甲苯為 96.95 %。而填充廢棄水泥塊SSF人工溼地系統，對於氯乙烯的去除率為 83.89 %，1,1-二氯乙烯去除率為 81.84 %、反 1,2-二氯乙烯為 56.50 %、順 1,2-二氯乙烯為54.81 %、甲苯為 -65.25 %。填充人造材料拉西環SSF人工溼地系統，對於氯乙烯的去除率為 92.08 %，1,1-二氯乙烯去除率為 75.24 %、反 1,2-二氯乙烯為 33.88 %、順 1,2-二氯乙烯為 27.12 %、甲苯為 81.02 %。各溼地系統的出流水中，除了順 1,2-二氯乙烯無法低於台灣環保署第二類地下水管制標準，其他關切污染物均可符合。而人工溼地所耗用的成本，約為傳統高級氧化系統的 20.8 %。
Reservation and management of water resources become significant issue due to drought and flooding problems caused by extreme climate recently. Groundwater is one of important freshwater resource for human life, but the industry and agriculture waste water and the chemical from the results of the industry production, transportation and storage percolate into the ground, and all these would cause pollution of groundwater. Chloro-organics is the most common pollution of the groundwater. At present, the techniques applied for groundwater decontamination require lots of money for energy and man-power. This collaboration project is trying to seek out feasible techniques for groundwater restoration and also with low cost or management requirement. Constructed wetlands (CW) have been proved to be low-cost and low-labor technique for polluted water treatment by several practical cases within the country. And CW can not only beautiful our environment but also save energy and reduce CO2 emission.
The industry collaborated in this project has mature techniques for monitoring and decontamination of groundwater. The goals of this collaboration projects are to use pilot-scale CW system to study the feasibility of treating chloro-organics polluted groundwater. The research topics include: 1. the characteristics of chloro-organics polluted groundwater for CW inflow and outflow; 2. comparisons of the treatability on various types of CW on chloro-organics polluted groundwater; 3. summarization of the research data and parameters to evaluation the costs of using CW for chloro-organics polluted groundwater.
In this study, natural gravels, recycled concrete debris, and artificial media (Raschig Rings), were used as media in a subsurface flow (SSF) CW to treat a groundwater polluted by Volatile Organic Compounds (VOCs) (mainly dichloroethene, DCE) so as to observe the efficiency of degrading of DCE. The experimental results shows that the removals rates of vinyl chloride, 1,1-dichloroethylene, trans-1,2-dichloroethylene, cis-1,2-dichloroethylene, and toluene were 70.30 %, 83.80 %, 53.94 %, 47.38 %, and 96.95 % in SSF with natural gravels; 83.89 %, 81.84 %, 56.50 %, 54.81 %, and -65.25 % in SSF with recycled concrete debris; and 92.08 %, 75.24 %, 33.88 %, 27.12 %, and 81.02 % in SSF with Raschig Rings operated within hydraulic time of 5-6 days. All treated target pollutants could match regulations in Taiwan, except cis-1,2-dichloroethylene under the research conditions. The costs of using SSF were estimated about 20.8 % comparing with application of advanced oxidation method on the same polluted groundwater. |
