垂直式與掃流式淤泥積垢指標之比較研究

A comparative study of dead-end and cross-flow fouling index

游雅淳(Ya-Chun Yu)

指導教授 ： 莊順興

朝陽科技大學/理工學院/環境工程與管理系/碩士(2012年)

摘要

全球面臨水資源逐漸缺乏與開發不易及水資源受到污染之問題，因此水資源再利用已成為各國重視及探討的重要議題之一，而在水質淨化等技術中，薄膜技術最具有研究潛力。一般常見判斷薄膜阻塞之情形的參數包括污泥密度指數 (Silt Density Index, SDI)、修正積垢指數 (Modified Fouling Index, MFI) 及微阻塞指數 (Mini Plugging Factor Index, MPFI)。
SDI 淤泥積垢指標為垂直式端點 (dead-end) 過濾，而實際工業應用薄膜過濾方式大多為掃流式(cross-flow)過濾，目前並沒有一套掃流式過濾之標準操作方法以及程序用以評估薄膜積垢，本研究將研發新的薄膜積垢指標，以便建立與實際面更為切合的應用指標，並且探討無機性顆粒、溶解性有機物質及生物處理程序放流水對積垢指標之影響。
研究結果顯示，無機性顆粒、溶解性有機物質及生物處理程序放流水於垂直式過濾時，SDI 指標均無法清楚區分水質積垢特性，MFI 指標比 SDI 指標更能夠看出其積垢特性，更適合作為積垢指標，其餘兩種指標則較無法區分水質之積垢特性。
無機性顆粒、溶解性有機物質及生物處理程序放流水於掃流式過濾時 SDI 指標於蛋白質及生物處理放流水中較能清楚區別水質之積垢特性，MFI 指標於無機性顆粒及葡萄糖物質中較能清楚區別水質之積垢特性，其餘兩種指標則較無法區分水質之積垢特性。
針對垂直式與掃流式兩種過濾裝置以四種指標進行數值分析比較，發現垂直式過濾裝置以 MFI 指標較能展現水質之積垢特性，而掃流式過濾裝置以 SDI 於大分子量及成分複雜之物質中能展現其積垢特性，而 MFI 指標於小分子量及單一顆粒物質中較能展現水質之積垢特性。
掃流式過濾裝置進行無機性顆粒、溶解性有機物及生物處理放流水於不同操作壓力對薄膜積垢指標之影響，發現其 SDI 值於壓力增加時會隨之遞增，其積垢程度能看出其差異，故以 SDI 指標較能呈現其積垢程度，而 MFI 值於壓力增加呈現不規律之現象，無法呈現其積垢程度，故無法展現其積垢特性。

關鍵字

掃流式過濾 ； 垂直式過濾 ； 微阻塞指數 ； 污泥密度指數 ； 修正積垢指數

並列摘要

Facing the global water resource shortage issues, many countries pays more attention on water reuse issue. In water purification technologies, membrane technology possesses the most valuable research potential. The parameters for judging membrane plugging situations include SDI (Silt Density Index), MFI (Modified Fouling Index) and MPFI (Mini Plugging Factor Index).
SDI is a kind of dead-end filtration; however, membrane filtration in industrial application mostly is cross-flow filtration. Currently, there is no whole set of standard operation method and procedure for cross-flow membrane fouling evaluation. In this study, a new membrane fouling index will be researched and developed in order to build up more proper applicable index for practice, and explore the influence from inorganic particles, dissolved organic matter and biological effluent on fouling index.
The research result shows that inorganic particles, dissolved organic matter and biological effluents in dead-end filtration, SDI is unable to clearly distinguish the characteristic of water quality fouling. MFI is clearer than SDI in observing the characteristic of fouling, it is more suitable as fouling index, and the other two indexes are unable to distinguish the fouling characteristics of water quality.
Inorganic particles, dissolved organic matter and biological effluent in cross-flow filtration, SDI is able to distinguish fouling characteristic of water quality in protein and biological effluent. MFI is able to distinguish fouling characteristic of water quality in inorganic particles and glucose, the other two indexes are unable to distinguish the fouling characteristics of water quality.
Numerical value is analyzed and compared by four kinds of indexes focusing on dead-end and cross-flow filtration devices; we discover that dead-end filtration device is able to show the fouling characteristics of water quality with MFI. And cross-flow filtration device is able to show the fouling characteristics of water quality in high molecular weight and complex substance with SDI, and then, MFI is able to show the fouling characteristics of water quality in low molecular weight and single particulate matter.
The influence on membrane fouling index from cross-flow type of filtration device proceeding with inorganic particles, dissolved organic matter and biological effluent in different operating pressure, we discover that SDI value will ascend when pressure is increased; it is able to present its fouling extent with SDI. The MFI values present irregular phenomenon under pressure increment, it is unable to present its fouling extent; hence, to present its fouling characteristic is not possible.

並列關鍵字

Cross-Flow Filtration ； Dead-End Filtration ； Silt Density Index ； Mini Plugging Factor Index ； Modified Fouling Index

參考文獻

1. Allison, R.P., “Electrodialysis reversal in water reuse applications” ,

Desalination, 103(1-2), 11-18(1995)

2. Bae, T.H., Tak, T.M., “Interpretation of fouling characteristics of ultrafiltration membranes during the filtration of membrane bioreactor mixed liquor” , J. Membr. Sci, 264, 151-160(2005)

3. Boerlage, S.F.E., Kennedy, M.D., Aniye, M.P., Abogrean, E. Tarawneh, Z.S., Schippers, J.C., “The MFI-UF as a water quality test and monitor” ,J. Membr. Sci, 211, 271-289(2003)

4. Bowen, W.R., Calvo, J.I., Hernandez, A., “Steps of membrane blocking in flux decline during protein microfiltration” ,Journal of Membrane Science, 101(1-2), 153-165(1995)