本研究主要探討在表面自由流動式(free water surface, FWS)溼地系統與表面下流動式(subsurface flow, SSF)溼地系統中種植不同種類的水生植物對除草劑2,4-D((2,4-dichlorophenoxy acetic acid)的處理效能。人工溼地系統由進流水儲存桶以並聯方式分別連接三個FWS溼地系統及三個SSF溼地系統，每個溼地系統規格長0.67m、寬0.48m、深0.32m。FWS溼地底部覆土18cm，分別種植蘆葦、香蒲及不種植任何植物的空白對照組；SSF溼地則填滿礫石，孔隙率約為45%，分別種植蘆葦、香蒲及不種植任何植物的空白對照組。進流水由自來水中調配1~2mg/L的2,4-D及磷酸鹽約3mg/L以模擬含除草劑的農地逕流水。HRT為5天，水力負荷約為0.03m/d操作。結果顯示SSF溼地系統的處理效能較FWS佳，具有28.02~88.72%的去除效率，而FWS溼地系統為13.01~83.83% 。比較不同種類水生植物的去除效能方面，發現SSF及FWS溼地中香蒲的生長狀況均優於蘆葦，且其系統的去除效能也較佳，顯示香蒲較蘆葦能夠處理2,4-D且具有忍受度。同時由SSF及FWS型系統中，有種植物的溼地系統其2,4-D的去除效率均較無種植植物的對照組系統來的高，顯示水生植物的存在有助於2-4-D的降解。 This research was using free water surface (FWS) and subsurface flow (SSF) constructed wetland (CW) systems which planted different macrophates to treat an artificial wastewater containing herbicide, 2,4-D, to study the treatment efficiency. The influent water flowed into three FWS and SSF systems which were connected in series , and the length, wide and height were 0.67, 0.48 and 0.32 meter. The bottom of FWS systems were planted cattails and reeds in 18cm deep soil and the SSF systems were planted into gravels. The hydraulic retention time (HRT) was controlled at about 5 days. Water samples were taken at inflow and outflow of the systems regularly. Data showed the removal efficiency of SSF system were 28.02~88.72% better than 13.01~83.83% of FWS systems, and cattails were better than reeds. The increase of Cl- showed the degraded of 2,4-D in constructed wetlands.
