- 學位論文
高壓與常壓薄膜生物處理反應槽操作於不同污泥停留時間下透膜壓力之比較
Comparison of TMP in elevated and ambient pressure membrane bioreactors under various SRT
摘要
MBR為薄膜分離機制與生物處理的結合，具處理水質佳、佔地面積小、汙泥產量少等優點。但薄膜阻塞一直是MBR程序最大問題。在固定的通量操作下，隨過濾時間增長而薄膜開始阻塞，導致TMP上升，若薄膜阻塞情形太嚴重會減短薄膜的使用壽命並提高操作成本。 文獻指出提高DO可降低薄膜阻塞，故本實驗利用加壓的方式，以3kg/cm2壓力提高密閉MBR反應槽的DO濃度，並設置常壓MBR反應槽做比對。於固定通量下，自反應槽中將固定量之汙泥廢置控制汙泥齡於60 day、5 day、15 day、15 day（實驗編號分別為D-1、D-2、D-3、D-4），之間的差異在於常壓MBR反應槽的掃流量控制，前三者為連續式，後者為間歇式。 本研究探討高壓MBR與常壓MBR反應槽的SMP與EPS濃度的變化，及間歇式與連續式提供薄膜空氣掃流量對薄膜阻塞的影響。實驗結果顯示，無論操作SRT的長短，SMP-PN及EPS-PN的濃度，沒有明顯的變化；而SMP-PS及EPS-PS濃度會隨SRT增加而減少。由TMP結果顯示，操作於D-1、D-2、D-3時，發現常壓MBR反應槽TMP較高壓MBR反應槽TMP容易上升，故以D-4將高壓MBR與常壓MBR反應槽皆以間歇式提供掃流量，發現間歇式掃流量能降低薄膜阻塞。
並列摘要
Membrane bioreactor combines physical mechanism of membrane separation and biological treatment. Compared to conventional biological treatment process, MBR has many benefits like a better treated water quality, a smaller footprint, less sludge production. However, MBR process is plagued by membrane fouling. Membrane fouling gets worse with progress of filtration, causing increase of TMP under a fixed flux condition. If the membrane fouling is too serious, then the life of the membrane will be shortened and as a result operating costs will increase. According to literature, high DO level can reduce membrane fouling. In this study, high DO was achieved by operating MBR at elevated pressure of 3 kg/cm2 in confined reactor, and a MBR at ambient pressure was operated side by side for comparison purpose. Pre-determined amount of sludge was wasted from bioreactor to maintain SRT of 60 days, 5 days, 15 days, and 15 days, respectively. These experiments are denoted, respectively, as D-1, D-2, D-3 and D-4. The difference between D-3 and D-4 is aeration flow for membrane fouling control. The former has continuous aeration flow, while the latter has intermittent aeration flow. This study explores effects of SMP and EPS in elevated and ambient pressure MBR on membrane fouling, and effects of continuous or intermittent aeration flow for controlling membrane fouling. Experimental results show that the concentration of SMP-PN and EPS-PN changed insignificantly with SRT; however the concentration of SMP-PS and EPS-PS decreased with increases of the SRT. Results show that TMP rising, i.e., membrane fouling, is faster for MBR operated at the ambient pressure than at the elevated pressure for experiment D-1, D-2, and D-3. One the other hand, TMP rising is comparable for both systems, indicating that intermittent aeration flow can mitigate membrane fouling.