Reclamation of wastewater polluted with antihypertensive drug residues by the biological+solar-photocatalytic sequential treatment plant

The quality of polluted wastewater processed by conventional Wastewater Treatment Plants (WWTPs) is in some cases insufficient to reach the degree of purity required. Pharmaceuticals are frequently identified in the aquatic environment, owing to their constant release from WWTPs. Thus, in recent years, they are cataloged as pseudo-persistent pollutants having been recognized as potentially harmful to public health and environmental concern. This work has focused on the removal of 3 antihypertensive pharmaceuticals (furosemide, irbesartan, and valsartan) from aqueous waste solutions using a sequential biological-photocatalytic (TiO2/Na2S2O8) treatment under natural sunlight. Pharmaceutical residues were isolated from water by solid phase extraction (SPE) and analyzed by HPLC-QqQ-MS2. Biodegradation was greater than 65% and 70% for irbesartan and furosemide, respectively, while valsartan was highly biodegradable (> 96%). Next, photocatalytic treatment was applied and just 200 kJ m-2 was required to remove 90 % of micropollutants residues from the effluent. Therefore, the coupling of biological treatment to solar heterogeneous photocatalysis constitutes a valuable instrument to detoxify polluted wastewater.