Aeration optimization in a submerged membrane bioreactor

Treatment of a synthetic oily wastewater has been carried out in an airlift submerged membrane bioreactor (AMBR). A flat sheet Kubota membrane has been used in the AMBR with working volume of 19 L. In this work, optimum specific aeration rate for high biological removal efficiency of pollutants, high oxygen transfer rate (OTR) and low membrane fouling was studied. Different parameters such as volumetric oxygen transfer coefficient, oxygen uptake rate and pollutants removal efficiency were investigated at different specific aeration rates. The results showed that the volumetric oxygen transfer coefficient and OTR were increased with increasing of aeration rate. However, the flocs size was reduced and hence fouling intensity of membrane was increased with augmentation of aeration rate. In addition, the highest COD removal and lowest membrane fouling was observed at specific aeration rate of 6.36 m3/m2.h. This work shows that in the studied range the 6.36 m3/m2.h is the optimum specific aeration rate and change of this specific aeration rate decrease the performance of the AMBR.

Keywords:

MBR , Aeration , Mass transfer rate , Fouling , Biomass