Bench-Scale Evaluation of Hydraulic Performance and Rejection of Bisphenol-A and Estradiol by Different Nanofiltration Membranes as a Post-Treatment Step at the Lago Norte WTP—Brasília/DF, Brazil

Emerging micropollutants in drinking water sources represents a growing challenge for water treatment systems. Bisphenol-A (BPA) and 17β-estradiol (E2) are endocrine disruptors widely detected in aquatic matrices that are not efficiently removed by conventional treatment. This study evaluated, at the bench scale, operational performance and rejection of BPA and E2 by three nanofiltration membranes—NFM1, NFM2 and NFM3—operating at 8 bar and using ultrafiltered water from the Lago Norte Water Treatment Plant (WTP), Brasília/DF, Brazil, spiked with both compounds at 150–250 µg/L, as the feed matrix. Hydraulic parameters, such as permeate flux and water permeability, were assessed alongside rejection. NFM1 exhibited the highest permeate fluxes (136.1 and 171.7 L/h·m2); however, it showed the lowest rejection (E2: 57–73%; BPA: 28–60%). The NFM2 membrane showed intermediate rejection behavior (E2: 86–89%; BPA: 67–91%) but presented the lowest permeate flux (51.2 to 63.3 L/h·m2). The NFM3 membrane presented the highest rejection and greatest operational stability (E2: 90–95%; BPA: 95–97%), with a permeate flux of 59.1 to 67.0 L/h·m2. Size exclusion was the predominant removal mechanism, though adsorption also contributed during the initial hours of operation. The results confirm a trade-off between permeate production and contaminant rejection, with no single membrane outperforming all others across all criteria.