An overview of homogeneous and heterogeneous photocatalysis applications for the removal of pharmaceutical compounds from real or synthetic hospital wastewaters under lab or pilot scale

Abstract

The last few decades, Pharmaceutical Active Compounds (PhACs) have been considered as emerging contaminants due to their continuous release and persistence to aquatic environment even at low concentrations. A growing number of research articles have shown the occurrence of numerous PhACs in various wastewater treatment plant influents, hospital effluents, and surface waters all over the world. The rising concern regarding PhACs, which present high recalcitrance towards conventional treatment methods, has provoked extensive research in the field of their effective remediation. This review provides a comprehensive assessment of homogeneous and heterogeneous photocatalytic applications for the removal of PhACs, from real or artificial hospital wastewater effluents. These two representative advanced oxidation processes (AOPs) are assessed in terms of their efficiency to remove PhACs, reduce the COD and toxicity as well as increase the biodegradability of the effluent. Simultaneously with their efficiency the operational costs of the processes are considered. Their potential combination with other processes is critically discussed, as this option seems to enhance the treatment efficiency and simultaneously overcome the limitations of each individual process. Moreover, the type of reactors as well as the main parameters that should be considered for the design and the development of photoreactors for wastewater treatment are reviewed. Finally, based on the literature survey, indications for future work are provided.

Keywords: Heterogeneous photocatalysis; Hospital; Pharmaceuticals; Photo-Fenton treatment; Wastewaters.