薄膜蒸餾法兼具傳統薄膜法和蒸餾法的優點，有可能取代其他如傳統蒸餾法與逆滲透等技術，但目前卻尚未商業化，其中最主要的原因可能為結垢問題，因為薄膜結垢無法避免，故減緩結垢是MD是否能成功商業化的重要因素。
因為適當的前處理為減緩薄膜結垢最有效的方法，所以在本文中先用單一的前處理單元(包括1μmMF、砂濾、活性炭、離子交換樹脂、紫外光殺菌)來處理真實海水，觀察去除特定結垢物對於薄膜結垢的影響，結果顯示，1μmMF和紫外光能有效的減緩薄膜結垢。為了尋求一套簡單、有效率的前處理系統，本研究比較四組前處理系統來處理真實海水，此四種前處理系統的配置為：(1)砂過濾+活性炭吸附+離子交換樹脂 (System 1)；(2)紫外光+1μmMF (System 2)；(3)紫外光+ 0.2μmMF (System 3)；(4)紫外光+0.001μmUF (System 4)。實驗顯示，利用UV殺菌再加上微或超微過濾能非常有效地減緩薄膜結垢，使滲透量提高，運轉時間延長。
從過去的研究中得知，超音波清洗能有效地清除薄膜結垢，並且使衰退的滲透量回復。本文中，使用掃描式電子顯微鏡(Scanning Electron Microscopy, SEM) 來觀察薄膜經超音波洗淨前後的表面。當飼水經由較佳的前處理(UV+0.2μmMF和UV+UF)之後，和經由傳統前處理之後所產生的結垢，經由相同的超音波清洗，發現經較佳的前處理的薄膜結垢物能較完全地被去除。

Among many seawater desalination methods, membrane desalination (MD) possesses the advantages that exist in the conventional membrane separation and that coming from the conventional distillation methods. However, MD method has not yet become available for commercial application. Since, the MD process is a thermal-driven method, fouling is more likely to accumulate on MD membrane than that on RO membrane. Membrane fouling thus posts as one of the major obstacles for MD method to compete with other desalination method. Up to this point, membrane fouling is inevitable, but can be effectively mitigated by a proper pretreatment before MD separation.
In this study, different single-pretreatment modules (including 1μm MF, sand filter, GAC, ion exchange resin, ultraviolet) was used to investigate the individual effect on membrane fouling. Results show 1μm MF and UV can effectively slow down membrane fouling. In order to seek a more effective pretreatment system, four combination systems were selected to perform the desalination tests. These pretreatment systems are: (1) sand filter + GAC + ion exchange resin (system 1); (2) UV + 1μm MF (system 2); (3) UV + 0.2 μm MF (system 3); (4) UV + 0.001 μm UF (system 4). Results obtained from system tests indicate that UV+ 0.2μm MF and UV + 0.001μm UF can more effectively slow down the fouling speed and extend the operation time.
From our previous investigations, ultrasonic cleaning technique was found very effective in cleaning out the membrane fouling and restore the declining permeate flux. In this study, the details of membrane structure before and after ultrasonic cleaning were examinated by SEM (scanning electron microscope). The foulant accumulated under a better pretreatment system(such as UV+ 0.2μm MF and UV + UF) can be removed more thoroughly than the foulant accumulated under a traditional pretreatment system and cleaned up by the same ultrasonic cleaning device.

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