3D electrochemical cork granule process for the removal of pharmaceuticals from urban wastewater

This study evaluates a three-dimensional (3D) electrochemical process employing cork granules as particle electrodes for removing contaminants of emerging concern (CECs) from urban wastewater. Tests in two reactors of different dimensions (Reactor A - 150 mL; Reactor B - 750 mL), with and without spiking of sulfamethoxazole (SMX) and trimethoprim (TMP), were performed and compared with the conventional 2D process and the use of a commercial activated carbon as 3D particulate electrode. The 3D cork process outperformed both the 2D process and the use of activated carbon, achieving higher removal efficiencies and lower energy consumption. In fortified wastewater, Reactor A achieved removal rates of 87 % for SMX and 59 % for TMP within 30 min. Reactor B led to complete SMX removal (below detection limits) and 81 % reduction in TMP, also showing 35 % reduction in energy consumption due to an increased electrode active area to reactor volume ratio. When applied to urban wastewater, 26 CECs could be detected. Over 80 % of 19 compounds were removed, and 15 of them were eliminated (below detection limits). Although using sodium chloride as an electrolyte enhanced the process efficiency, producing chlorine-reactive species may cause a hazardous impact on aquatic ecosystems, according to the ecotoxicity tests performed, suggesting the need for their removal. The Life Cycle Assessment results further underscore the environmental competitiveness of the cork-based 3D electrochemical process, highlighting its potential as a sustainable quaternary treatment for urban wastewater. This study also provides insights into optimizing the process for future large-scale applications.