Start-up of the anammox process and membrane fouling analysis in a novel rotating membrane bioreactor Original Research Article

A rotating flat-sheet membrane bioreactor (RFMBR) was employed to start up anammox process, in comparison with a conventional membrane bioreactor (CMBR). The anammox process was successfully started up within around 16 days in both bioreactors. The particle image velocimetry (PIV) analysis showed a larger velocity gradient and a stronger shear stress on membrane surface in RFMBR than in CMBR. At the end of the experiment, the mean particle size of anammox granules achieved 899 μm in RFMBR, while the value reached 809 μm in CMBR, and the trans-membrane pressure (TMP) reached 4 and 16 kPa in RFMBR and CMBR, respectively. Furthermore, the scanning electron microscope (SEM) observation of the biofilm formed on membranes illustrated that a much thinner biofilm with the thickness of 35 μm was formed in RFMBR, compared to the value of 120 μm in CMBR.