以膠羽影像光訊號分析(FICA)技術監測高嶺土之化學混凝; Monitoring the coagulation of kaolin with Floc Image Color Analysis (FICA) technology

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Title:	以膠羽影像光訊號分析(FICA)技術監測高嶺土之化學混凝;Monitoring the coagulation of kaolin with Floc Image Color Analysis (FICA) technology
Authors:	賴虹任;Hung-jen Lai
Contributors:	環境工程研究所
Keywords:	混凝;光學監測;硫酸鋁;高嶺土;image analysis;kaolin;coagulation;alum
Date:	2010-12-22
Issue Date:	2011-06-04 15:05:17 (UTC+8)
Publisher:	國立中央大學
Abstract:	混凝是水處理中固液分離的重要程序之一，而在混凝過程中存在著許多因子影響混凝的好壞，其中混凝劑的加藥量是最難控制的一個，目前是由瓶杯實驗及操作經驗來決定加藥量，常有過量加藥的問題，造成藥劑量及後續污泥處理成本的提高。本研究團隊已發展化學混凝之非接觸式監測系統，以期能夠快速得知混凝加藥之成效，唯系統對不同處理條件之適用性並未詳盡調查，也缺乏實廠原水之驗證。本研究以高嶺土水樣為模擬原水，調整溶液在不同濁度、不同酸鹼值及不同混凝劑劑量下，探討快混階段之RGB變化與RGB值之標準偏差值與顆粒之關聯性。在小型模場中監測不同操作情況，其光訊號變化之情形，並且搭配粒徑分析儀來觀察膠羽顆粒長成的效果，以建立此系統更加完善的可行性。在混凝過程中膠羽顆粒的變化確實反應在RGB值上，快混過程中之RGB值下降趨勢愈明顯時，混凝效果愈好，慢混過程中RGB跳動幅度愈大，其膠羽顆粒亦較大。透過斜率值之計算可以得到RGB值之變化大小，以分辨混凝效果好壞，藉由斜率-加藥量關係圖可以判定混凝有效藥劑範圍，避免藥劑之浪費。另外，由實驗得知從RGB值之標準偏差值可看出顆粒是否有大小落差，以作為顆粒是否有長成之判斷依據。 Coagulation is an important solid-liquid separation process in potable water/wastewater treatment. Among all the control factors for coagulation, the dosage of coagulant is the most difficult to control. The dosage of coagulant is usually determined by jar test or the experience of operators, which usually leads to an overdose of coagulant. Overdose of coagulant causes high cost for chemicals and for on sludge treatment. So far, in our laboratory, a monitoring system for coagulation process, floc image colorimetric analysis (FICA), to resolve the problems mentioned above has been developed; however, the responses of the monitoring system for various coagulation conditions are not clear and the applications of the system in the control of coagulant dosage have not been clarified yet. In this research, modeled turbid water is made by kaolin particles. The responses of the FICA to various coagulation conditions, such as initial turbidity, solution pH, and coagulant dosage were investigated. The evolution of RGB values of the suspension images were analyzed. During coagulation, the solution images varied as the particles grew; as the consequence, the RGB values of the images changed correspondingly.. When the coagulation was effective, the RGB values decreased significantly within rapid-mixing. Then, as the flocs became bigger, the RGB values jumped up as the flocs passing through the observation window and dropped down due to the clear solution during the slow-mixing process. It was found that the slope of the RGB values during rapid-mixing could be used to monitor the coagulation efficiency. As the coagulation efficiency increased, the solution becomes clearer and, thus, the RGB dropped significantly and the slope of RGB values increased. .It is also found that the optimal dosage of coagulant occurred when the slopes of RGB values first hit the bottom. In other words, the optimal coagulation condition could be determined right after the rapid-mixing from jar test, which is much faster than the traditional method. In addition, the standard deviation of the RGB values increased with increasing particle size due to brighter images of flocs.
Appears in Collections:	[Graduate Institute of Environmental Engineering ] Electronic Thesis & Dissertation

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