淨水場濁度去除效能評估及混凝監測之研究-以豐原淨水場為例

Abstract

工商高度發展的今日,水質日趨惡化,提昇淨水場淨水處理的能力及改善其操作方式已是當 務之急.本研究先對豐原淨水場現有設備及混凝加藥操作情況做一全面得評估,針對混凝, 沈澱及過濾等處理程序,了解各單元濁的去除效能是評估重點.結果顯示淨水場內混凝及過 濾單元皆處於超負荷狀況,沈澱單元的負荷量也相當大. 而針對淨水場內混凝加藥處理單元的最適化,我們在現場採用光纖膠羽偵測技術(以下簡稱 PDA)進行了混凝加藥監控的研究.首先進行 PDA 批次實驗,改變不同濁度, pH值及快混強度的 實驗條件,以觀察 PDA Ratio 輸出值,殘餘濁度,膠羽生成大小及沈降速度. 接下來在淨水場架設連續流式的混凝沈澱處理單元的模型槽,模擬淨水程序.結果顯示 PDA 模型系統在連續流的狀況下,對於不同濁度與混凝加藥量其輸出訊號依然 能保持穩定.而現場 加藥故障的狀況, PDA 也能即時地作出反應. Water quality has been deteriorated by the excess development in the catchmen t. It is desirable to pay more attention to improve or upgrade the performance of existing water treatment plant.In this study,we first made an comprehensiv eevaluation to the plant units ant their chemical dosing in Feng-Yuan water tr eatment facility.The turbidity removal efficiency was a key parameter to condu ct this task. The results from the evaluation of plant units clearly that soli d removal units including flocculators,clarifier,and filters are all in the ov erloading opera--tions,especially for the flocculator and filter. As for the o ptimization of chemical dosing to the coagulation,we applied a Photometric Dis persion Analyzer (PDA) to determine the chemical dose as well as to monitor the coagulation performance.Aseries of batch trials in the field were perform ed to explore the effects of turbidity,pH and the rapid mixing intensityon the PDA monitoring.The results show that "Ratio" output of PDA provides an effect ive index for the flocs size as well as the potential of flocs settlingvelocit y. We also assessed the feasibilty using PDA monitoring in the continuous mode with influent same as Feng-Yuan water treatment facility.The results show th at the "Ratio" values of this optical montor system remain stable when dealing with different turbidity and coagulant dosages.The "Ratio" output alsogave a prompt response to a suddenly change situation when the dosing system failed t o work normally.