散氣式曝氣系統氧傳輸效率之探討－以膜片式細氣泡散氣盤為例

The investigation on oxygen transfer efficiency for diffused aeration system-Taking membrane fine bubble diffuser as an example

葉明燦(Ming-Tsan Yeh)

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在職專班/碩士(2011年)

摘要

曝氣是一項主要控制活性污泥的程序，其可藉由各種方法來達成。在此，本論文是針對膜片式細氣泡散氣盤的性能之研究。模型系統相似於實際的曝氣池，也就是深度3~4 m，用來消除小規模研究會產生的尺寸效應。在總氧傳輸係數(KLa20)上試驗了幾項效應包括：溫度、水深、曝氣速率、鹽濃度。溫度修正係數被證實與ASCE的建議值是近似的。研究發現，係數(KLa20)在氯化鈉在200 mg/L以內會呈現先下降後再上升，而在200 mg/L之後趨緩下降。其與懸浮固體的效應相似，但原因仍不明。研究取樣來自兩個城市污水及一個有機顏料業污水，實驗其傳氣係數和修正係數(α)。研究發現，雖然城市污水來自不同地方，其成份有些微的不同，但是其修正係數值是相似的，其值約為0.67至0.69。然而，有機顏料業廢水的修正係數卻是毎批與批之間有較大的變動。研究結果指出，由於污水性質的變化，曝氣效率可能會相對受到影響，因此，導致活性污泥系統的操作不穩定。

關鍵字

曝氣 ； 膜片式散氣盤 ； 總氧傳輸係數

並列摘要

Aeration is a key control activated sludge processes, which can be achieved by various methods. The performance of membrane fine bubble diffuser was studied here. A model system similar to real aeration tank, that is, depth of 3~4 m, was used to eliminate the size effects in studies of small scale. The effects of temperature, water depth, aeration velocity, and salt concentration on the overall oxygen transfer coefficient (KLa20) were examined. The temperature correction factor was confirmed to be similar to that suggested by ASCE. The KLa20 was also found to be decreased than increased before 200 mg/L of sodium chloride and remained similar after that. It was similar to the effects of suspended solids, for which the reason is still not clear. The oxygen transfer coefficient and correction factors of two different municipal wastewaters and a organic pigment wastewater were examined. It was found that although the municipal wastewater came from different places and the compositions of them were slightly different, the values of the correction factors are similar, which is 0.67 ~ 0.69. However, for the organic pigment wastewater, the correction factors varied significantly from batch to batch. The result suggested that due to the variation in wastewater quality, the aeration efficiency might be affected correspondingly and, therefore, the performance of activated sludge system was not stable.

並列關鍵字

overall oxygen transfer coefficient ； membrane diffuser ； aeration

參考文獻

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