Anaerobic MBRs

An interesting practical application of fluidized beds and membranes is the fluidized bed anaerobic MBR [109]. In this work, a fluidized bed of granular activated carbon (GAC) is successfully used to control membrane fouling. The GAC is liquid fluidized and avoids the need to recirculate biogas for membrane cleaning. 

A cost analysis and comparison between two anaerobic processes for the treatment of wastewater was also carried out by Pillay et al. [6.23]. The first configuration consisted of a conventional system coupling a digester with a sedimentation unit. In the second configuration the sedimentation step was replaced by a membrane separation unit treating a side stream. Pillay et al [6.23] report that for a 60 Ml d plant the MBR process results in capital savings of about 27 % when compared with the classical configuration. 

Kani, M., Ferre, V., Wakahara, S., Yamamoto, T., More, M. (2010). A novel combination of methane fermentation and MBR—kubota submerged anaerobic membrane bioreactor process. Desalination, 250, 964—967. 

MBR (1) [Membrane BioReactor] A system that combines a suspended growth bioreactor with a membrane filtration device. Most systems involve aeration in which the bubbles minimize fouling of the membrane anaerobic systems are used in special situations. Widely used in water and wastewater treatment since the 1980s. In 2012, it was offered by 13 companies. 

Process flow diagrams for the MBR option are presented in Figure 7.3. The inclusion of primary clarification and aerobic or anaerobic digestion as a function of flow rate is identical to the CAS-TF case. Also, for all but very small plants, the membranes are immersed into separate tanks from the main bioreactors. This provides more flexibility in isolating membranes for cleaning or maintenance without handling. 

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