Photocatalytic treatment of high concentration carbamazepine in synthetic hospital wastewater

Effective and sustainable treatment of hospital wastewater containing high concentration of pharmaceutical compounds presents a pivotal challenge to wastewater and environmental engineers worldwide. In this study, a titanium dioxide (TiO ₂) nanofiber based wastewater treatment process was assessed as a pre-treatment system to treat and enhance the biodegradability of a representative pharmaceutical compound, 5000μg/L of carbamazepine (CBZ), in synthetic hospital wastewater. Results showed that the stand-alone TiO ₂ pre-treatment system was capable of removing 78% of CBZ, 40% of COD and 23% of PO ₄ concentrations from the influent wastewater within a 4h reaction time. High performance size exclusion chromatography demonstrated that a simultaneous biodegradability enhancement of hospital wastewater was observed, whereby an apparent shift in molecular weight from higher fraction (>10-1000kDa) to a lower fraction (<10kDa) was induced after 0.5h of photocatalytic treatment. Eventually, it was found that the photodegradation profile for high concentration CBZ in synthetic hospital wastewater was perfectly fitted to the Langmuir-Hinshelwood kinetics model. It is anticipated that this TiO ₂ pre-treatment process can be further integrated with a biological wastewater treatment process to deliver treated hospital effluent of better quality that can minimise the associated human health and environmental risks.