有機物對污泥氈澄清池特性及生成潛能之影響探討

Abstract

台灣地區污泥氈澄清池產水量約佔全台50%以上，但台灣地區水體中因含大量天然有機物以至於降低了污泥氈澄清池對於濁度與有機物的處理效能。雖然污泥氈澄清池對無機顆粒去除之因子在國外早廣泛論述，但對於有機物種類和濃度對於污泥氈之影響卻相當欠缺，本實驗中以腐植酸以及水楊酸添加於人工原水中以模擬天然水體中有機物成分，探討天然有機物存在下，對於污泥氈澄清池之效能、膠羽性質及泥氈生成之影響。 研究結果發現，在固定之操作參數下，腐植酸存在下污泥氈重量百分率低，污泥脫水性佳，膠羽粒徑較大，泥氈生成時間快，且易受水流剪力淘淅，而水楊酸則呈現相反結果，但二者之污泥氈對於濁度去除效果差異不大。而當降低污泥氈混凝劑量時，雖然會使污泥氈生成時間變長，但並不影響出流水濁度變化，影響上澄液出流濁度之最大因子乃污泥氈操作流速，並非混凝劑量，故降低上升流速可獲得良好的濁度去除效果。 污泥氈處理程序對於腐植酸等大分子有機物去除效果頗佳，而對於水楊酸等小分子去除效果較差。

Abstract

In Taiwan, approximately 50% of the drinking water production relies on sludge blanket clarifiers. Most of the surface water bodies contain a large amount of natural organic matters, which deteriorate the treatment efficiency for turbidity and organic substances. Although sludge blanket clarifiers have been broadly studied, they are mostly on the removal of inorganic particles. Few paid attention to the significance of organic species and their concentrations on the performance of sludge blanket clarifiers. The object of this study was to study the effect of organic compounds on sludge blanket clarifiers. Humic acid and salicylic acid were used to simulate the organic compounds of the natural water. The forming of the sludge blanket, its efficiency and the characteristics of the flocs were examined. Experimental results revealed that in the presence of humic acid, the sludge blanket formed in a shorter period of time, which contained lower solids. It had better dewaterability, with bigger particles. The blanket was much easier to washout. Opposite result was discovered in the presence of salicylic acid. When the coagulant dosage was reduced, longer time was required to form the sludge blanket although no significant effect on the turbidity of the effluent was observed. The most critical operation factor for residual turbidity was the flow rate rather than the coagulant dosage. In addition, sludge blanket clarifier was more efficient for larger organic molecules like humic acid.