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A comparative pilot-scale evaluation of gas-sparged and granular activated carbon-fluidized anaerobic membrane bioreactors for domestic wastewater treatment

Evans, Patrick J., Parameswaran, Prathap, Lim, Kahao, Bae, Jaeho, Shin, Chungheon, Ho, Jaeho, McCarty, Perry L.
Bioresource technology 2019 v.288 pp. 120949
biochemical oxygen demand, chemical oxygen demand, cost effectiveness, membrane bioreactors, municipal wastewater, permeability, sewage treatment, temperature, total suspended solids, ultrafiltration
Two significantly different pilot-scale AnMBRs were used to treat screened domestic wastewater for over one year. Both systems similarly reduced BOD5 and COD by 86–90% within a 13–32 °C temperature range and at comparable COD loading rates of 1.3–1.4 kg-COD m−3 d−1 and membrane fluxes of 7.6–7.9 L m−2 h−1 (LMH). However, the GAC-fluidized AnMBR achieved these results at a 65% shorter hydraulic retention time than the gas-sparged AnMBR. The gas-sparged AnMBR was able to operate at a similar operating permeability with greater reactor concentrations of suspended solids and colloidal organics than the GAC-fluidized AnMBR. Also, the membranes were damaged more in the GAC-fluidized system. To better capture the relative advantages of each system a hybrid AnMBR comprised of a GAC-fluidized bioreactor connected to a separate gas-sparged ultrafiltration membrane system is proposed. This will likely be more effective, efficient, robust, resilient, and cost-effective.