不同混凝劑對原水濁度去除效能之評估及生物濾床前處理之影響

Abstract

不同混凝劑與生物濾床對原水濁度去除效能之評估 研究生：陳俊哲 指導教授：黃志彬 國立交通大學環境工程研究所 摘 要 科技發達的今日，水質日趨惡化。在環保意識抬頭，法令逐漸嚴格之情形下，追求更好的水處理工程技術已是當務之急。本研究乃以硫酸鋁、氯化鐵、PACl以及PFS四種化學藥劑為混凝劑，評估其對急水溪原水濁度去除之效果；此外，評估以生物濾床為前處理單元時，對處理效能之影響。 批次實驗中，改變不同混凝劑種類、混凝劑加藥量以及沈澱溢流率之實驗條件下，觀察上澄液之殘餘濁度，結果顯示氯化鐵為最適混凝劑。而針對最適混凝劑做延伸實驗，觀察其在不同pH值、混凝劑量之條件下，對殘餘濁度、界達電位值以及顆粒分佈之影響，以尋找最佳操作條件。 接下來架設連續流式之混凝沈澱處理單元模型槽，模擬實廠淨水程序。藉由改變不同進流量以及慢混轉速之配搭兩種實驗條件，觀察出流水濁度以及顆粒分佈之關係，評估處理效果與膠羽生成情形。結果顯示，較小流量之條件下，處理效果較佳；而慢混轉速以84 rpm及42 rpm此種漸減式慢混（Gt值為79,226），膠羽生成情況最佳。

Evaluation of Various Turbidity Removal Performance by Various Coagulants and the Effects by Biofiltration Pretreatment Student : Chun-che Chen Advisor : Chihpin Huang Institute of Environmental Engineering National Chiao Tung University ABSTRACT Raw water quality is deteriorating because of the excessive development in industries. It is necessary to search for better water treatment techniques in order to meet the more stringent environmental regulations. Evaluations were made on the performances of various coagulants, such as aluminum sulfate, ferric chloride, PACl and PFS, on removing the turbidity from raw waters of high turbidity. The efficiency of biofiltration in improving turbidity removal were also evaluated. A series of batch trials in the field were performed to explore the effects of various overflow rate, coagulant and its dosage. The results show that ferric chloride is the most efficient coagulant. The most optimal operation conditions were evaluated by measuring residual turbidity, zeta potential and particle distribution. We also assessed the feasibility of using particle sizer in monitoring the turbidity in a continuous mode of operation. The results showed that lower flow rate with a longer hydraulic retention time achieved better efficiency, and the tapered flocculation induced larger floc size.