| 摘要註: |
本研究分別進行模槽及實場試驗探討大型植物控制自然淨化系統中藻類生長情形。模槽試驗主要利用不同大型植物遮蔽、化學殺藻及物理遮蔽型態，包括挺水、浮水、沉水性植物及添加硫酸銅和黑布覆蓋。本研究探討遮蔽效應控制藻類生長情形，而試驗水源分別取自後勁溪畜牧廢水及人工濕地氧化塘兩種，兩水源之藻類生長情形於控制組皆由於無遮蔽效應，導致藻類滋生情形最為嚴重，五天之監測期間兩原水，畜牧廢水及人工濕地氧化塘，葉綠素a濃度分別由39.5 μg/L及214.1 μg/L上升至296.2及306 μg/L，而藻類滋生對水質影響，同時導致水體懸浮固體及有機物濃度COD上升。植栽大型植物與物理化學等處理方式，兩水源皆對於藻類生長控制具顯著成效，畜牧廢水原水部份，其葉綠素a濃度由39.5 μg/L，經植栽布袋蓮、水芙蓉、蘆葦、香蒲及金魚草五日後，葉綠素a濃度分別升為58.1、39.5、59.2、49.4及118.5 μg/L，而氧化塘原水部份其葉綠素a濃度由214.1 μg/L，經植栽布袋蓮、水芙蓉、蘆葦、香蒲、黑布覆蓋及添加硫酸銅五日後分別降至125.8、66.8、85.6、82.5、27.8及37.5 μg/L情形，兩原水植栽相較於控制組，具顯著差異情形。實場試驗監測列車式人工濕地系統及校園生態池，藉由迴歸分析結果其葉綠素a濃度與濁度、SS及COD皆呈正相關，並且監測自然淨水系統中全日參數，包括溶氧、pH值及照度，全日溶氧及pH值隨日照增減，乃由於水中藻類行光合作用及呼吸作用所致，故自然淨水系統中藻類滋生將影響水質背景參數(濁度、SS及COD)及水質處理效率。調查監測校園生態池，其葉綠素a濃度由入流處178.1 μg/L，流至生態池處濃度上升至307.2 μg/L。本系統濁度由入流處10 NTU上升至生態池處之27 NTU，SS由入流處之9.7上升至生態池處34.3 mg/L，而COD則是12.8上升至23 mg/L情形，實驗顯示藻類滋生將嚴重影響自然淨化設施之放流水質，且水質優養化導致魚群缺氧致死。大腸桿菌於實場及模槽結果類似，大型植物易使附著性生物生長，且模槽試驗中浮水、挺水植物與人工濕地表面流二入流階段，挺水植物生長密集，植物體提供遮蔽陽光效應，降低紫外光殺菌機制，使植物存在該區域大腸桿菌去除效果較差。而校園生態池系統大腸桿菌去除率部份，受到漫地流河道淺僅15cm，在此主要受紫外光殺菌效果影響，使大腸桿菌總去除率達91.7%。實場藻種鑑定部份，結果發現氧化塘係以綠藻為主要型態，然而表面流與生態池中則發現藍綠藻及矽藻影像，其中藍綠藻為多數影像型態，監測像是Synechocystis、Oscillataria皆為富含營養水域中之藻種，而藍綠藻與綠藻適應污染環境能力佳，容易產生過度繁殖情形導致魚類暴斃死亡或影響自然淨水系統之處理效率，此相關問題為國內類似自然淨化系統急待解決之問題。 This study was aimed to control the growth of algae in the natural water purification systems employing both batch mesocosms experiments and field-scale natural system. The batch mesocosm experiments employed different macrophytes, including floating macrophytes, emergent macrophytes, and submersed macrophytes as well as physical light shading. The addition of algaecide cupric sulfate, and black cover to treat the shading effect on the growth of algae was also treated. Two source waters, the Hou-Jin River water and oxidation pond water. Were sampled to conduct the aforementioned test. compared to the control groups, due to no shading effect, the algae concentrations in the two sources waters increased significantly. Based on the 5-day monitoring, the concentration of chlorophyll-a for river water and oxidation pond water rised from 39.5 μg/L to 296.2 μg/L and 214.1 to 306 μg/L. The algae bloom deteriorate the water quality. affection on water quality. SS, COD, and turbidity were strongly correlation with the algae concentrations. Regarding the macrophytes planting method and the physical and chemical method, for both water sources, the methods had obvious effect on controlling the growth of algae. The concentration of chlorophyll-a for original livestock waste water was 39.5 μg/L, when the water hyacinth, water cabbage, reed, cattail, and snapdragon were planted in the water for 5-day monitoring, the concentration of chlorophyll-a rose to 58.1, 39.5, 59.2, 49, and 118.5 μg/L separately. The concentration of chlorophyll-a for original oxidation pond water was 214.1 μg/L, when the water hyacinth, water cabbage, reed, cattail, and snapdragon were planted in the water for 5-day monitoring, the concentration of chlorophyll-a dropped to 58.1, 39.5, 59.2, 49.4 and 118.5 μg/L separately, with the cover of black cloth and the addition of cupric sulfate. If the planting of the two water sources was compared to the one of the control groups, there was an outstanding difference.The field-scale natural system experiment was used to monitor hybrid constructed wetlands and campus ecological ponds, and through the result of regression analysis, there was a positive correlation among the chlorophyll-a, turbidity, SS, and COD. Besides, the whole-day parameter in the natural water purification system was also monitored, including dissolved oxygen, pH value, and illumination. The whole-day dissolved oxygen and pH value increased or decreased with the change of sunlight, and this was because of algae’s photosynthesis and respiration. After realizing that the breeding of algae in the natural water purification system would affect the background for parameter of water quality and the processing efficiency of water quality, there was a survey and monitor in the campus ecological pond. The concentration of chlorophyll-a was 178.1 μg/L at the entrance of inflow, and rose to 307.2 μg/L in the ecological pond. The turbidity of the system was 10 NTU at the entrance of inflow, and rose to 27 NTU in the ecological pond ; SS was 9.7 mg/L at the entrance of inflow, and rose to 34.3 mg/L in the ecological pond. COD rose from 12.8mg/L to 23 mg/L. The breeding of algae seriously affected the water quality produced by natural water purification systems, and the eutrophication led to the death of fishes due to hypoxia. The results of total coliforms in batch mesocosm experiment and field-scale natural system experiment are similar. Macrophytes are easy to stimulate the attached microorganism growth. About the floating macrophytes and emergent macrophytes in batch mesocosm experiment and the FWS-II influent, the growth of emergent macrophytes was dense, and the plant offered light-shading effect. The effect would reduce the disinfection mechanism from solar radiation (UV) to let the remove effect on total coliforms for the plant in the area become worse. Regarding the remove rate of total coliforms in the system, as the depth of river on the ground was only 15cm, the area was mainly affected by the UV disinfection effect, and the remove rate of total coliforms was up to 91.7%. As for the identification of algae in field-scale natural system experiment, the result indicated that chlorella was the main pattern in the system. However, the images of blue-green algae and diatoms were found in FWS and ecological pond, and the blue-green algae accounted for the most part of the images. The monitored images, like Synechocystis and Oscillataria, are those algae, which appear in nutrient-rich waters. The blue-green algae and diatoms are with better ability to adapt to polluted environments, and their over breeding easily leads to the death of fishes or affects the processing efficiency of natural water purification systems. |