The Efficacy Assessment and Feasibility Study of Artificial Floating Island in Sun Moon Lake

• Main Authors: Ming-jih Cheng, 鄭銘日
• Other Authors: Jiunn-Jer Wu
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/23090374103437228218

碩士 === 逢甲大學 === 環境工程與科學所 === 94 === The nutrient loadings including phosphor and nitrogen, caused by the reconstruction of recreation facilities after 921 Earthquake and the water intaking from Wu-Chieh Dam, has potentially increased the occurrence of eutrophication for Sun Moon Lake that is an important water resource in central Taiwan for power generation and water supply. Since artificial floating island (AFI) for water purification in reservoirs has been demonstrated as a viable technique for eutrophication restoration in some developed countries, this research was focused on the efficacy assessment and feasibility study using AFI in Sun Moon Lake. Three locations, including Te Hwa village, Shueishe village, and Moon Lake, under the permission by administrative bureau were determined to set up AFI facilities for further evaluation. Among all AFI’s plants, Typha orientalis is ranked to have the greatest average weight growth rate, then Angelonia goyanzensis and Hygrophila pogonocalyx, and Ruellia brittoniana and Celosia argentea have the lowest growth rate. According to the growth data from controlling different initial height for plants, it shows that the initial height between 10~15 cm for Angelonia goyanzensis, Hygrophila pogonocalyx, and Typha orientalis are better. The optimal harvesting frequency based upon the planting location and the adaptation characteristics of plants is between 2 and 5 months. In addition, it shows that Hemerocallis fulva, Silene pendula, Chrysanthemum frutescens, and Salvis leucantha have better growth status in winter period. Climatic factors including temperature, wind velocity, sunshine intensity, and water temperature, were found to have close relationships with plant growth in AFI facilities. During the test period, it shows that Typha orientalis has the greatest uptaking rate for nitrogen and phosphor among AFI’s vegetations, then following the order by Angelonia goyanzensis and Hygrophila pogonocalyx. According to the estimation from Vollenweider model, which is based on the zero-dimensional assumption, the reduction for nitrogen and phosphor loadings to assure the water quality for Sun Moon Lake achieving oligotrophic status in the future are calculated to be 236,550 and 2,100 kg/year, respectively. The demand of vegetation area for the use of AFI by solely planting Typha orientalis, which has the highest uptaking rate for nutrient, are 920,000 and 60,000 square meter at least for nitrogen and phosphor remediation in Sun Moon Lake.