Membrane bioreactor performance improvement by adding adsorbent and coagulant: a comparative study

Membrane bioreactors (MBRs) have become popular in recent years due to its excellent organic pollutants removal efficiency. However, its popularity has been restricted by a major constraint which is high maintenance cost incurred by membrane fouling in the system. Currently, hybrid MBRs with additives were found efficient in controlling membrane fouling. In this study, the performance of two additives consist of powdered activated carbon (PAC) and alum in enhancing membrane fouling control in MBRs were determined and compared. Three 6L laboratory-scale submerged MBRs known as conventional MBR (without additive), MBR-PAC (added with PAC), and MBR-Coagulant (added with alum) with SRT 30 were set up. It was observed that the MBRs with additive could enhance MLSS concentrations by about 7–13% and reduce the protein concentration (one of the main foulants) by 43–70%, respectively. The results revealed that by adding alum and PAC into the MBRs, membrane fouling control of MBRs could be improved. MBR-PAC performed best in this study as it could be operated steadily without any sign of transmembrane pressure “jump” as compared to the other two MBRs even it was operated under “stress” condition by treating high strength wastewater during the experimental filtration period.