Efficient treatment of baker’s yeast wastewater using aerobic membrane bioreactor

A 0.15 μm dead-end immersed hollow fiber membrane and filamentous fungus Aspergillus oryzae were used in a membrane bioreactor (MBR) for treatment of baker’s yeast wastewater. The fungus was adapted to the wastewater in the bioreactor for two weeks before continuous process. Average organic loading rate of 4.2 kg COD/m3.d was entered the bioreactor. COD and BOD5 of the wastewater were reduced to 488 and 70 mg/L, respectively, over a period of 45 days, while the turbidity of the wastewater reduced from 134-282 NTU to less than 2.5 NTU in the permeate stream. Critical flux and a suitable operating flux were determined as 6.7 and 5 L/m2 h, respectively. The system was able to efficiently reduce the turbidity and suspended solid by 99.4% and 98.3%, respectively, resulting in a clear effluent.