決定薄膜生物反應槽臨界通量之研究

Critical flux determination of membrane bioreactor

張維運(Wei-Yun Chang)

指導教授 ： 游勝傑

中原大學/工學院/土木工程學系/碩士(2008年)

https://doi.org/10.6840/cycu200800435

摘要

近年來薄膜生物處理程序(MBR)在處理廢水之上有很好的效果，但要廣泛的應用MBR需要控制薄膜產生積垢的問題。有研究指出薄膜在次臨界操作中，能有效降低薄膜產生機構的現象。本研究針對中原大學薄膜中心所研發的PTFE薄膜，利用二種批次實驗，測試不同污泥濃度(MLSS)下不同親疏水性之通量與壓力變化，並以五種判斷臨界通量的方法推算薄膜之臨界通量。隨後將薄膜操作在MBR中，觀察五種判斷臨界通量的方法是否能貼近長期真實的次臨界操作，最後再利用不同污泥停留時間(SRT)改變污泥特性，觀察SRT對於臨界通量之影響。本研究發現在批次實驗中，五種判斷方法所決定之臨界通量皆有所不同，並隨MLSS濃度的提高而降低。親疏水性在MLSS濃度小於4,000 mg/L之下有些微影響，但當污泥濃度超過4,000 mg/L之後就無明顯差異。利用積垢速率與滲透性變化之判斷臨界通量的方法，操作30天之後，通量與壓力之比值依然保持穩定，可進行長期操作；但其他三種方法在真實操作之下皆會產生嚴重積垢，操作天數皆低於10天。而MBR操作在高SRT下，雖然MLSS濃度較高，但是薄膜較不易產生積垢；操作在低SRT下，雖然MLSS濃度較低，但薄膜會產生積垢而阻塞。本研究同時發現在長的SRT之下有較大的顆粒與較少的EPS，因此可能是造成薄膜較不易阻塞之原因。

關鍵字

親疏水性 ； 臨界通量 ； 薄膜生物反應槽 ； 薄膜積垢

並列摘要

The application of membrane bioreactor (MBR) for the wastewater treatment has gain more advantages recently. However, membrane fouling need to be consider for it’s industrial application. The major parameter which controls the fouling rate.Many study indicated that membrane fouling can be effectively decrease by operating MBR system below critical flux. In the study , the experiment was done uder two batch condition to study the effect of different hydrophobicity of PTFE membrane (CYCU R&D Center for Membrane Technology) and different MLSS concentration on TMP and flux. Long-term performance of reactor was tested using five methods evaluate critical flux under real operation.The effect of different SRT on sludge characteristics and critical flux was also studied.The result showed that the critical flux determined using different methods was different.The critical flux was slighty affected by membrane hydrophobicity at lower MLSS concentration ( <4,000 mg/L) and it was negative at higher MLSS concentration ( >4,000 mg/L). The MBR system can be operated over 30 days by fouling rate and permeability methods due to it’s low fouling rate and below 10 days by other methods. The membrane fouling was observed to be much higher at a short SRT as compared to longer SRT. The result showed that longer SRT the rate of fouling was lower maybe due to lower EPS concentration and higher particle size distribution.

並列關鍵字

critical flux ； hydrophobicity ； MBR ； fouling

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