金門太湖水庫優養化之溶氧分層特徵與底層增氧改善效率研究

The Characteristics of Stratified Dissolved Oxygen and the Aeration Efficiency in Bottom Level of Water in Shallow and Eutrophic Reservoir Taifu in Kinmen

侯文祥(Wen-Shang Hou) ； 梁維真(Wei-Ten Lieng) ； 游政勳(Chen-Hsun Yu) ； 葉曉娟(Hsiao-Chuan Yeh) ； 陳以容(I-Zon Chen)

《農業工程學報》 53卷4期 (2007/12) Pp. 44-55

https://doi.org/10.29974/JTAE.200712.0004

摘要

針對供應自上來水的金門太湖小型水庫，夏季水深的5m，在2005年11月和2006年5月，發生藻華現象的各二日夜期間，每四小時，間隔0.5m垂直水層，實測日夜間溶氧的垂直分層特徵，且在底水層以低造價的微細氣泡增氧設備行小區域增氧改善示範研究。測試設備在日夜間的增氧效率，包括15分鍾緊急增氧能力試驗、2小時與24小時溶氧擴散效率試驗，以探討溶氧分層與藻華聚集水層及與時間變化的關係。得知藻類多浮游於約2m以內上水層，尤其在表水1m內的密度最高。在光合作用減慢後，水藻2m以下的下水層溶氧即迅速降低。底水層明顯缺氧，清晨時降至2ppm以下，甚達近壓氧狀態。確定太湖水庫的底水層應考慮進行長期有效的增氧改善。在水溫24℃的夏季藻華狀況，0.5Hp微細氣泡機約可增加27~35%的溶氧飽和度。以太湖發生藻華的水質狀況，得知一支0.5HP動力微細氣泡機的配置間隔可設計爲30至40m。以110v動力供應的設備，每組不含施工的造價1萬元，可改善水體底層面積約1250平方公尺、水體體積約6250立方公尺。

關鍵字

金門 ； 太湖水庫 ； 優養化 ； 溶氧 ； 微細氧泡 ； 曝氣效率 ； 底層水

並列摘要

The Taifu Reservoir about 5 meter depth in summer supplies drinking water in Kinmen. However in November 2005 and May 2006, the algae bloom phenomenon was occurred. The characteristics of stratified dissolved oxygen (DO) were measured every 0.5m of water depth, four hours a time for 24 hours. The low-cost micro bubble aerator was used in bottom level water to carry on the demonstration research of aeration improvement in a pilot test at about 80 meter square area. The aeration efficiency tests lasted for 24 hours included the emergent aeration capability test after aerating 15 minutes, the DO diffusion efficiency tests after aerating 2 hours and 24 hour, in order to study the relationship of stratified DO level and algae bloom gathering water level as time went by. It was known that most of algae were suspended within the 2 meter deep, especially the density was the highest within the 1 meter of surface. As the photosynthesis slowed down, the DO reduced rapidly after 2 meter depth. The bottom level was shortage of oxygen obviously, it was decreased below 2 mg/l in early morning, sometimes even close to anaerobic state. It was clear that a long term and effective aeration improvement for the bottom level of water in Taifu Reservoir was necessary. When the water temperature was 24℃ and the algae bloom happened in summer, the 0.5 horsepower (HP) micro bubble equipment can improve the situation by increasing about 27~35% of DO concentration. The installation space for the 0.5HP equipment can be designed per 30m to 40m in accordance with the algae bloom condition in summer. The material costs are about 10000 taiwan dollars. The range of estimated improved condition can reach 1250m^2 of bottom water area and about 6250^3 of water volume.

並列關鍵字

Kinmen ； Taifu reservoir ； Eutrophication ； Aeration efficiency ； Dissolved oxygen ； Micro bubble ； Bottom level of water