Efficiency of Water Turbidity Removal by Composite Sand Filter System

• Main Authors: Ren-tai Yao, 姚仁泰
• Other Authors: Ming-Chee Wu
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/64558399304147485302

碩士 === 國立成功大學 === 地球科學系碩博士班 === 95 === After the 921Chi-Chi Earthquake, The earth materials of mountain area in Taiwan were loosened and rock weakened. With steep slope and weakened rocks, debris of rocks and soils will fall into the water during typhoon or raining season; thus cause the turbidity of water body to jump up. Most reservoirs in Taiwan are in-basin reservoirs. Debris of rocks and soils from upstream regions can easily be flashed into the reservoirs; namely, water treatment plant of public water supply system was frequently forced to close down due to the high water turbidity. Water treatment plant of Shihmen Reservoir was closed down due to the high water turbidity during the typhoon season has been the most well known incident in 2005. It had widely affected the public water supply in southern Taoyuan region. Purpose of this work was set to quickly lower the turbidity of intake water in order to match the capability of water treatment plant; namely to obtain a stable water supply even during the extreme weather season that may highly increase the turbidity of the water body. A sand filter system was adopted to evaluate its efficiency on removal of water turbidity. Water of different turbidities was made by using the earth materials from Gutingkeng formation mudstone of Kaohsiung area, Taiwan. The turbidity removal efficiency due on the different grain size sand filter layer and different infiltration flow rates was evaluated, in respectively. Results of the experiments showed that a 40% efficiency of turbidity removal can be obtained by using 0.425~0.710 mm grain size sand filter layers under the designated infiltration flow rate.