Comparison between a fluidized bed membrane bioreactor and a conventional membrane bioreactor for municipal wastewater treatment

A new-type membrane bioreactor was constructed with the addition of granular activated carbon, which combined the advantages of membrane separation with fluidized bed, called fluidized bed membrane bioreactor (FBMBR). Parallel test was carried out between FBMBR and a conventional membrane bioreactor (MBR) for municipal wastewater treatment. Results show that FBMBR is a reliable and effective technology in terms of both membrane fouling mitigation and pollutants removal improvement. As compared to MBR, FBMBR exhibited a better pollutants removal with removal rates of 97.2% for COD, 96.3% for NU4+-N and 67.1% for TN. Due to the addition of biological fixation, both attached biofilm and suspended sludge were dominant in EBMBR, which was essentially different from MBR. The dehydrogenase activity in FBMBR was higher than that in MBR with the mean of 17.8 and 12.8 mu g-TF/(mg-MLSS.h), respectively. The unique fluidizing characteristic and mixed liquor composition in EBMBR alleviated the process of membrane fouling effectively, and the backwashing period was doubled compared to MBR.