提昇混凝沈澱對有機物之去除：生物濾床前處理之影響

Abstract

人為的過度發展，造成飲用水源的污染日益嚴重，有機物的污染除了造成飲用上臭味、色度之問題外，有機物與氯反應所衍生之消毒副產物 (Disinfection By-Products)，經證實為一致癌物最為引人關切。 很多文獻結果顯示現有淨水廠之混凝沈澱單元對有機物去除效率並不高，為有效解決有機物問題，已有很多研究投入有機物混凝之探討，因每一原水之污染特性皆不相同，因此本研究將針對新營之受污染原水－急水溪原水進行有機物與濁度去除評估。本實驗以批次Jar Test實驗評估原水及生物濾床出流水經硫酸鋁與氯化鐵混凝去除有機物，並進行模廠連續穩定試驗。模廠架設於新營水廠，模廠主要處理單元為一組生物濾床前處理反應槽，及混凝沈澱處理單元。 由研究結果顯示，原水及生物濾床出流水硫酸鋁、氯化鐵混凝有機物理想pH分別為5.3 – 6.0與5.0 – 5.5，有機物初始濃度與最適混凝劑量存在化學劑量關係，而生物濾床出流水之有機物所需的化學劑量小於原水；濁度在理想有機物去除的混凝條件下，亦可有效去除。

Potable water quality is deteriorated because of human excessive development. Organic matters caused pollution of odor and taste, besides it produced trihalomethanes (THMs). Human pay attention to THMs because they are cancerogenic chemicals. Coagulation/Sedimentation unit of conventional water treatment has low efficiency for removing organic matters coagulation, but water quality is varied. This study is to evaluate the removal efficiency of organic matters of polluted water in Hsin-in. Jar test is used to evaluate the result of coagulation of raw water and biofiltration pretreatment effluent water. Pilot scale is performed to evaluate continuously steady experiment. Pilot scale has a set of biofiltration pretreatment and Coagulation/Sedimentation. The results show that optimal pH of raw water and biofiltration effluent water coagulated with Alum and ferric chloride are pH 5.3 – 5.9 and pH 5.0 – 5.5. Concentration of initial organic matters is stoichiometric with optimal coagulative dosage. The removal efficiency of organic matters of biofiltration effulent water is higher than that of raw water.