Aluminum dioxide (Al2O3) flat-tubular ceramic membrane was applied in a novel staged anaerobic fluidized bed ceramic membrane bioreactor (SAF-CMBR) for low-strength wastewater treatment. Granular activated carbon (GAC) particles were fluidized by bulk recirculation through the membrane reactor to control membrane fouling without any biogas sparging. The SAF-CMBR was operated for 350 days at 25 °C with total hydraulic retention time (HRT) between 1.3 and 2.1 h. A net permeate flux of 22 L/m2 h was achieved during the reactor operation combined with periodic maintenance cleaning using 25 mg/L of sodium hypochlorite solution under GAC fluidization. The overall chemical oxygen demand (COD) removal efficiency was 93%; with average SCOD was less than 30 mg/L in membrane permeate. Energy requirement to operate the SAF-CMBR was 0.024 kWh/m3 and it was only 10% of the electrical energy converted from methane produced by the reactor. Biosolids production averaged 0.01 g volatile suspended solids per g COD removed. With SAF-CMBR, microbial classification revealed that anaerobic treatment was achieved mainly by microbial communities grown on the GAC particles fluidized in which propionate-degrading syntrophs, aceticlastic/DIET-dependent CO2 reduction methanogens Methanothrix and exoelectrogenic Geobacter were dominated. •Staged anaerobic fluidized bed ceramic membrane bioreactor was developed.•Net flux of 22 LMH was achieved under GAC fluidization and maintenance cleaning.•Overall COD removal of 93% was achieved with less than 30 mg/L COD in permeate.•Only 10% of electrical energy produced by the reactor was required for system operation.•Methanothrix and Geobactor were dominantly grown on GAC particles as fluidized media.