Removal of Indicator Micropollutants Included in Directive (EU) 2024/3019 Using Nanofiltration and Reverse Osmosis

Contaminants of emerging concern (CECs) comprise a diverse group of substances whose presence in the environment is of increasing concern due to their potential negative effects on human health and the environment. Multiple studies have concluded that nanofiltration (NF) and reverse osmosis (RO) membrane separation mechanisms are effective barriers for organic pollutants, showing generally high removal efficiency. In this study, nine indicator CECs included in the Directive (EU) 2024/3019 concerning urban wastewater treatment were selected and used as a reference to calculate the removal percentage of all micropollutants present in the influent of wastewater treatment plants (WWTPs). According to the regulations, a minimum average removal percentage of 80% of the influent load must be achieved by analyzing at least six out of a set of twelve micropollutants, including those considered in this study. The treatments were conducted using three commercial RO membranes and one commercial NF membrane. Our findings indicate that membrane technology alone can remove over 80% of the micropollutants studied, except benzotriazole. An analysis of the separation mechanisms was carried out to understand the performance of each CEC in relation to each membrane type, taking into account pollutant physicochemical properties and observed removal efficiencies.