Takuro MATSUMOTO

Effect of Carrier Addition in a Membrane Bioreactor Treating Real Sewage

Toshiya KOMATSU, Shoichi FUJITA, Shuji HIMENO

Nitrogen can be efficiently removed in a single-reactor membrane-separation activated sludge process by operating the reactor with intermittent aeration. This study was conducted to examine the effect of carrier addition into the reactor for investigating the possibility of improving nitrogen removal efficiency and membrane filterability. Real sewage (effluent from the grit chamber in a sewage treatment plant) was used as wastewater. We conducted continuous operation of reactors for 50 days with and without carrier in summer. The hydraulic retention time (HRT) of the system was set up at 6 hours. As the results, operation with carrier showed superior performances in both nitrogen removal efficiency and the maintenance of membrane permeate flux. We also operated reactors for 50 days with and without carrier in winter. Better performances were observed in the reactor with carrier, same as the case of operation in summer. Moreover, in the reactor with carrier, it was demonstrated that the strength of aeration can be reduced sharply. Results of this study suggest that the addition of carrier in the system is effective for not only improving treatment performance but also saving energy.