Combining submerged membrane technology with anaerobic and ...

Chapter 1A more recent advance in this field has been the study of the so-called fluxenhancers (Koseoglu et al., 2008; Iversen et al., 2008; Guo et al., 2008). Membrane fluxenhancers (MFE) are a modified cationic polymer capable of reducing membrane fouling.Moreover, aeration energy savings in the range of 20-60% can be achieved due to anenhanced flux and a slightly better oxygen transfer (Yoon and Collins, 2006; Iversen et al.,2009).In general, all the additives mentioned above may be especially useful to handle thepeak flow conditions that could take place in a real wastewater treatment plant.1.6. Other submerged membrane technologies for wastewatertreatmentThere are other different membrane technologies that are being developed or appliedfor wastewater treatment: Anaerobic membrane bioreactors (AnMBR) in which methanogenic biomass isused for treating the wastewater Biofilm MBR in which the growth of biofilms in carrier particles is promoted. Hybrid suspended biomass-biofilms membrane bioreactors, in which both biofilmsand suspended biomass grows in the bioreactor. Methanogenic-aerobic MBRs, which are a combination of a first methanogenicstage and a second stage in which the remaining COD fraction is treated aerobically in aMBR.1.6.1. Anaerobic membrane bioreactor (AnMBR)Anaerobic treatment of domestic wastewater can be very interesting and costeffectivein countries were the priority in discharge control is in removal of organicpollutants. Anaerobic biomass has very low biomass yield, which eliminates one of thecrucial disadvantages of aerobic treatment. However, at low temperatures, which would bethe case for domestic wastewater treatment, the growing rate of these microorganisms,and thus the capacity for degrading organic compounds diminish. For this reason, it isimportant to avoid any loss of anaerobic biomass with the treated water. The anaerobicMBR (AnMBR) is a combination of an anaerobic reactor coupled with the membrane unit.According to how the membrane is integrated with the bioreactor, two MBR processesconfigurations can be identified: submerged and side-stream AnMBR.46