石門水庫分層取水對於平鎮淨水廠快濾池堵塞成因分析

Filter clogging in Pin-Chen water treatment plant during water intake from intake well in Shimen reservoir.

張嘉元(Jia-yuan Jhang)

指導教授 ： 秦靜如

國立中央大學/工學院/環境工程研究所/碩士(2012年)

摘要

石門水庫因颱風暴雨時期原水濁度過高，以建設分層取水工程來因應淨水廠難處理之問題，但淨水廠以分層取水做為水源時，在淨水廠末端快濾池操作上發生嚴重堵塞問題，進而影響出水水質及水量，本研究藉由採樣分析石門水庫不同取水口水質差異以及快濾池現況調查；另一方面，藉由模廠試驗，控制在不同物化條件進行過濾試驗，釐清快濾池堵塞成因。
水質分析結果顯示，石門水庫不同取水口以及平日取水與切換分層取水之平鎮淨水場進場水質，水質並無明顯差異，因此濾池堵塞原因受原水水質影響有限，爾後分別在平日取水與分層取水進行濾料鑽心分析，由反洗廢水濁度歷線、濾料膠羽濁度、SS 貯留、EDS 分析結果，淨水廠以分層取水做為水源時，快濾池過濾機制是以表面過濾為主，且可能為物理性堵塞，但排除顆粒過度累積所致。
平日取水時，以瓶杯試驗混沉後，殘餘濁度與過濾性較佳之混凝劑，在模廠快濾單元操作上，無法獲得較長濾程，由於處理後原水之殘餘濁度均相當低，因此無法判斷混凝劑種類與濾程之相關性。若以分層取水做為水源時，並非為混沉成效不佳，且模廠試驗得知，更換藥劑並不能解決快濾池堵塞問題；經由現場濾料鑽心分析、以及模廠試驗與觀察，推斷快濾池快速堵塞是原水中溶解氣體過飽和，導致濾池空氣閉塞現象。藉由曝氣程序模擬原水中氣體過飽和現象，但無法模擬出分層取水在導水過程中，管線中造成氣體過量溶入行為；最後在暴雨期，採取分層取水試驗，因濁度高氣體溶入量較少，經取水管線至淨水廠中，氣體與原水矽顆粒、混凝
劑形成大膠羽進而沉澱去除，使得快濾池有較長之濾程，此試驗結果亦可研擬平鎮淨水廠快濾池操作上，濾程縮短之對策。

關鍵字

濾料分析 ； 濾床堵塞 ； 快濾池 ； 空氣閉塞

並列摘要

Due to extreme high turbidity during typhoons or heavy rains, which resulted in difficulties in potable water treatment, the water intake well to draw water from upper levels of the reservoir was built in the Shihmen reservoir.
After drawing water from the intake well, it was found that the rapid sand filter was severely clogged, the head loss increased dramatically, and the filtration run-time was seriously shortened. The objectives of this study were first to investigate filter clogging in Ping-Jan Water Treatment Plant while intake water from the water intake well by water quality analysis of different water intake
locations, filter-bed analysis, and pilot study. It was shown that the water qualities from different water intake locations were similar; thus, the water quality was not the cause for the clogging. From the floc retention analysis, scanning microscopy, and energy-dispersive X-ray spectroscopy of filter media, it was found that the particles only deposited on the surface of filter while
intake water from the water intake well. Bubbles observed in coagulation tanks on-site and in coagulation, sedimentation, and filtration units of the pilot, it was
determined that the air-binding is responsible of the filter clogging.

並列關鍵字

rapid filtration ； filter clogging ； filter analysis ； air binding.

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