Integrating Membrane Bioreactor with Advanced TiO2 Photocatalytic Technology for the Removal of Pharmaceutical Drugs from Recycled Wastewater

The presence of pharmaceutical drugs and residues in wastewaters is of concern due the potential health and environmental risks when the wastewater is recycled as an alternative water source. This study investigated the application of an integrated membrane bioreactor with titanium dioxide photocatalytic technology (MBR-TiO2), as a combined treatment barrier to remove Carbamazepine (CBZ) from pharmaceutical wastewater. A laboratory MBR-TiO2 system was started-up, operated and monitored for its treatment efficiency with respect to CBZ concentration. Prior to the integration, the individual systems of MBR and TiO2 photocatalytic technology were monitored separately, in order to distinguish the synergistic operational effects. Respirometric tests showed that the introduction of CBZ acts as a chemical stressor, influencing the biomass metabolism in the MBR and resulting in reducing sludge yield. Thereafter, the chemical stressor effects were alleviated when the combined MBR-TiO2 system was operated in a 4:1 ratio. A maximum CBZ removal efficiency of 95% was observed, but the treatment efficiency was found to decrease with increasing number of treatment cycles possibly due to fouling by different organic and divalent ions found in wastewater.