Ultraviolet-based heterogeneous advanced oxidation processes as technologies to remove pharmaceuticals from wastewater: An overview

Contaminants of emerging concern including pharmaceuticals and personal care products are increasingly detected at low concentrations in surface waters. Given the associated toxicity of these compounds, there is the potential for significant impacts on aquatic life and the food chain. Since most pharmaceuticals are not biodegradable, they cannot be removed by secondary treatment processes in conventional wastewater treatment plants. Therefore, the development of alternative treatment methods plays a critical role in the removal of pharmaceuticals. Energy consumption is a key factor in technology selection, and the use of solar energy may help minimise operating costs. Thus, this work provides a comprehensive review of relevant research published between 2016 and 2021 targeting the removal of active pharmaceutical ingredients using ultraviolet processes, including photo-Fenton, photocatalysis and photoelectrocatalysis. While the focus remains on the development of novel catalysts and some efforts have been made to demonstrate the reuse of these materials for multiple cycles, there is little work aimed at scaling up the systems or investigating their efficacy in real water matrices to test the potential beyond the laboratory setting. The review concludes with some recommendations for future studies, highlighting the importance of comparing technologies in terms of life cycle assessment, energy use, and financial considerations to provide a holistic understanding of the role that these technologies can play in removing trace pharmaceutical compounds from wastewater.