LAUSR

Abstract This paper aims to investigate integration of biological process with photocatalytic oxidation for treating pharmaceutical wastewater characterized by simultaneous presence of biodegradable and refractory compounds. An integrated lab-scale biological system with a photocatalytic reactor (containing Degussa P25 TiO2 in slurry mode) was operated in batch mode to treat simulated wastewater containing 10 mg/L of the model compound, Atenolol (ATL). Biodegradability (BOD5/COD ratio) increased from 0.23 to 0.42 after 4 h of photocatalytic treatment (1.5 g/L TiO2) with COD removal of 69.7% when using a solar simulator. In the independent biological treatment, the amount of sludge was varied as 2, 5, 10 and 15% in simulated wastewater, to optimize sludge concentration at three different temperatures of 20, 27 and 37 °C. The maximum BOD and COD removal of 46.3% and 46.2% respectively was achieved with 5% activated sludge at 37 °C for 48 h at natural pH of 6.9 under continues aeration. By employing 4 h of photocatalytic treatment using TiO2 (1.5 g/L) followed by 48 h of biological treatment (37 °C, 5% Sludge concentration) resulted in 90.5% and 80.8% removal of COD and BOD, respectively. The study shows integration of the two processes can be a promising technology.