Double‐deck aerated biofilm membrane bioreactor with sludge control for municipal wastewater treatment

Alternative designs of an aerated moving‐bed biofilm reactor and a flat‐sheet membrane module for a biofilm membrane bioreactor process have been investigated to overcome a membrane clogging problem and to determine the performance of a new membrane module. Double‐deck aerated biofilm reactor with integrated designs of sludge hopper, thickener, and velocity‐zone concept for particle settlement was evaluated for the suspended solid control and removal. Hydrodynamics of bubbling, liquid, and solid particles were arranged in the bioreactor to obtain a particle settlement. New membrane modules used under low suspended solid environment having smaller membrane gaps were evaluated for filtration performance and clogging problems for long‐term operation. The average suspended solids concentration in the bioreactor effluent was 44.6 mg/L. Relaxation applied with the membrane module provided the most optimum result for fouling control, and no clogging problems in the modules were observed in the system after continuous operation of 3 weeks. © 2009 American Institute of Chemical Engineers AIChE J, 2009