Journal of Hazardous Materials, Vol.199, 135-142, 2012
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 (TiO2) nanofiber based wastewater treatment process was assessed as a pre-treatment system to treat and enhance the biodegradability of a representative pharmaceutical compound, 5000 mu g/L of carbamazepine (CBZ), in synthetic hospital wastewater. Results showed that the stand-alone TiO2 pre-treatment system was capable of removing 78% of CBZ, 40% of COD and 23% of PO4 concentrations from the influent wastewater within a 4 h 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 (>10-1000 kDa) to a lower fraction (<10 kDa) was induced after 0.5 h 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 TiO2 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. (C) 2011 Elsevier B.V. All rights reserved.