A novel anaerobic fluidized membrane bioreactor system: Improving process performance and fouling control

In this study, the effectiveness of a novel system of an anaerobic fluidized membrane bioreactor (AnFMBR) in treating wastewater was demonstrated and the results were validated by testing duplicate systems in parallel under similar operating conditions. In this novel system, an outer loop performs as an anaerobic reactor while an inner loop serves as an AnFMBR with granular activated carbon (GAC) used as a carrier and for fouling control. The GAC fluidization is restricted to the inner loop to minimize operational energy while ensuring membrane scouring. Fluidized GAC was a key factor in maintaining low TMP by attracting biofilm formation thus reducing attachment to the membrane surface and by removing deposits from membrane surface via abrasion. The new system improved fouling control as reflected in a slower buildup in transmembrane pressure (TMP) resulting in a 1.5 to 3.8 folds increase in typically reported operating periods for anaerobic membrane bioreactors (AnMBRs) and AnFMBRs. Similarly, energy requirements were estimated at 52 and 94% lower than those reported for typical AnMBRs and aerobic MBRs, respectively. At a validation level, both AnFMBR systems exhibited a similar performance with respect to several indicators including the microbial community composition, methane yield, chemical oxygen demand removal, TMP, and energy savings.