Integration of photocatalytic and biological processes for treatment of pharmaceutical effluent

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 4h 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 degrees C. The maximum BOD and COD removal of 46.3% and 46.2% respectively was achieved with 5% activated sludge at 37 degrees 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 degrees 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.