本研究為探討因季節性氣候改變，導致河水水質變化，而對人工溼地系統中水生植物所造成的影響。由於本系統設立於二仁溪出海口附近，於計劃研究期間，受到河水春秋翻騰及河川進入枯水期所導致的海水入侵之影響，造成人工溼地系統之水質變化頗大；尤其於河水進入冬季時變動最為劇烈。此計畫研究目的，即基於系統中植物適應能力受到水質變化的影響，就植物之特性即培養過程之變化加以探討，以期找出人工溼地系統應用於淨化污染河水之合適植物物種。在研究期間，所選種的植物以本土型水生植物為主，於自由表面流系統(FSF)中之浮水性植物選擇空心菜 (Lpomoea reptans) ；挺水性植物於研究初期種植狼尾草(Pennisetumalopecuroides L.)、水丁香(Ludwigia octovalvis)，後因期間季節變化及水質波動，導致生長不良而最後選擇蘆葦(Phragmites communis L.)。表面下流動系統(SSF)則種植蘆葦(P. communis L.)。二仁溪水的監測，時間為八十七年九月份至八十八年四月份，主要監測項目為一般營養鹽、懸浮固體(TTS)及物理性質。其中化學需氧量(COD)大約分布在50至330mg /L :氨氮則維持在3至15mg /L之間;磷酸鹽的濃度主要介於1至4mg /L之問: TSS的分布則十分廣，由數mg /L至一百多mg /L，尤其颱風期間，由於上游的沖刷，TSS可升至500mg /L以上。至於二仁溪水的物理性質，pH值維持在7至8之問;溶氧(DO)則介於1至8mg /L之間;鹽度在九月份為0%，受到河川進入枯水期之影響，至三、四月雨季來臨之前，鹽度升至2%左右;水溫在九、十月份介於攝氏28至29度之間，在十一、十二月份則介於攝氏21至25度之間，直到四月份又回升到29度。對於河水的處理效能，各污染物之平均去除效率分別為: COD 16.7%，氨氮78.3% :磷酸鹽56% ; TSS 75.8%，顯示濕地中水生植物具有增進溼地系統淨化水質的功能。同時發現季節、氣候之變化，將影響河川水質，進一步影響系統內水生植物的生長。在植物選擇方面，以抗鹽性較佳之禾本科植物為較理想，可解決因鹽度上升，所導致的植物適應不良。 This research was to investigate the effects of the varlation of river water quality due to the seasonal changes on the growth of macrophytes in a constructed wetland (CW) system. The Cw system located close to the estuary of Erh-Ren River, thermal strtificatlon of the river and seawater intrusion in the season of low river flow rate caused significant of the water quality in the influent of the CW system. Because that the adaptation of macrophytes In the CW system influenced by the quality of water; thus this research work will focus on the studies of the characteristics and the cultivation processes of vegetation in order to search for the practicable techniques of using CW systems in purifying polluted river water. The macrophytes selected in this research included a floating plant, Lpomoea reptans, and emergent plants, Pennisetum alopecuroides L. and Ludwigia octovalvis, in the free surface flow (FSF) reactor. The later two species were dead due to improper cultivation during the research period and Phagmites colmmunis L. was used for replacement. In the subsurface flow (SSF) system, P. communis L. The monitor of the watre quality of the Erh-Ren River covered the time period from September 1998 to April 1999. The monitoring parameters included general pollutants, total suspended solids (TSS) and some physical properties. The ranges of pollutants' concentrations were COD 50 to 330 mg/L, NH3-N 3 to 15 mg N/L, PO4-P I to 4 mg P/L, respectively. The TSS concentration ranged widely from a few mg/L to more than a hundred mg/L. The physical properies of the riverwater. pH maintained between 7 and 8 S.U. and D.O. ranged from 1 co 8 mg/L. Virtually no salinity was detected before September and started to increase gradually up to 2% before the raining season arrived in March. Water temperature was about 28 to 29℃ from September. and 21 to 25℃ during winter time. The average treatment efficiencies of pollutants in the CW system were COD 16.4%, NH3-N 73.4%, PO4-P 56.0%, and TSS 77.3%, respectively. According to the comparisons of treatment efficiencies in the CW and control systems we found that macrophytes could enhance the purifying ability on polluted water in the CW system. Changes of season or climate would effect the water quality in the river and further influence the growth of macrophytes. Therefore, the planting of the macrophytes. which can tolerate the pollutants and salt in water, should be able to maintain a consistent treating ability of the CW system in the carious season.
