This paper aims to demonstrate that integrating biological process and photocatalytic oxidation in a system operated in recycling mode can be a promising technology to treat pharmaceutical wastewater characterized by simultaneous presence of biodegradable and refractory/inhibitory compounds. A lab-scale system integrating a membrane bioreactor (MBR) and a TiO2 slurry photoreactor was fed on simulated wastewater containing 10 mg/L of the refractory drug Carbamazepine (CBZ). Majority of chemical oxygen demand (COD) was removed by the MBR, while the photocatalytic oxidation was capable to degrade CBZ. CBZ degradation kinetics and its impacts on the biological process were studied. The adoption of a recycling ratio of 4:1 resulted in removal of up to 95% of CBZ. Effluent COD reduction, sludge yield increase and respirometric tests suggested that the oxidation products were mostly biodegradable and not inhibiting the microbial activity. These results evidenced the advantages of the proposed approach for treating pharmaceutical wastewater and similar industrial effluents. (C) 2011 Elsevier Ltd. All rights reserved.