Urine from Intensive Care Patients as a Hotspot for Pharmaceutical Emissions and Sorbent-Based Treatment

Abstract

Pharmaceutically active compounds (PhaC) released into the environment can threaten human and environmental health. Their removal from (waste)water typically involves advanced water treatment technologies that are resource- and cost-intensive. This raises the question whether there are specific emission hotspots that would enable more targeted PhaC removal. In this study, we identify patient urine in hospitals as one such hotspot. PhaC concentrations in urine ranged from hundreds of μg/L up to tens of mg/L with some PhaC detected at concentrations above 20,000 μg/L. This concentration range is 3-4 orders of magnitude above what is found in wastewater. Intensive care unit patient urine, collected in urine drainage bags, is a promising point of intervention, as it can be easily separated from other waste streams and treated on-site. To screen for potential on-site treatment options, we tested the PhaC removal potential of a commercial activated carbon, a steam-activated biochar, and ion exchange resins in both batch and column experiments. These experiments showed that pore size distribution of activated carbon was a crucial factor for PhaC removal. Ion exchange resins were generally worse sorbents, including for charged PhaCs. Our results indicate that on-site PhaC removal from patient urine using carbon based sorbents is a promising approach to reduce PhaC emissions that warrants further investigation, but removal efficiencies need to be further improved by tailoring the sorbents and potentially pretreating the urine.