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。
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.