Rejection of pharmaceutically active compounds and endocrine disrupting compounds by clean and fouled nanofiltration membranes V. Yangali-Quintanilla a,b, *, A. Sadmani a , M. McConville a,b , M. Kennedy a , G. Amy a,b a UNESCO-IHE, Institute for Water Education, Westvest 7, 2611AX Delft, The Netherlands b Delft University of Technology, Stevinweg 1, 2628CN Delft, The Netherlands article info Article history: Received 27 November 2008 Received in revised form 11 February 2009 Accepted 19 February 2009 Published online 27 February 2009 Keywords: Pharmaceuticals Endocrine disruptors Nanofiltration Membrane Fouling abstract Rejections of 9 pharmaceuticals and 5 endocrine disruptors by clean and fouled nano- filtration membranes were investigated in this study. Waters containing a cocktail of compounds were filtered by clean and pre-fouled membranes. The rejection of hydrophilic neutral compounds by the clean NF-200 membrane varied from 35 to 70% under steady state conditions while that of NF-90 membrane was in the range of 62–96%. The clean NF-90 membrane rejected nearly all of the hydrophobic neutral compounds (95–98%) predominantly due to size exclusion. Nevertheless, electrostatic repulsion was the main mechanism of rejection of ionic compounds by both membranes (71–94% by NF-200 and 99% by NF-90). Fouling with sodium alginate deteriorated the performance of the NF-200 membrane in rejecting hydrophilic neutral compounds as well as hydrophilic and hydro- phobic ionic compounds. In contrast, rejections of hydrophobic neutral compounds by the fouled NF-200 membrane increased by 5–38%. This may be attributed to the incipient interaction of the solutes with the membrane foulant layer resulting in less partitioning and diffusion across the membrane surface. On the other hand, rejections of hydrophobic compounds by NF-90 were not observed to be affected by fouling; however, hydrophilic neutral compounds showed increased rejections by 7–30%. ª 2009 Elsevier Ltd. All rights reserved. 1. Introduction In the future, the ever growing demand for drinking water will lead many cities to implement indirect water reuse programs, where wastewater effluent is used as part of drinking water sources. Pollution of those sources with organic micro- pollutants such as endocrine disrupting compounds (EDCs) and pharmaceutically active compounds (PhACs) which have been detected in water supplies and wastewater effluents around the world pose health effects for consumers and the environment (Kolpin et al., 2002; Snyder et al., 2003; Ternes et al., 2004). Membrane filtration technology, particularly nanofiltration (NF) and reverse osmosis (RO), has demon- strated promising results on rejection of PhACs and EDCs. In order to examine the ability of RO membranes to retain PhACs and EDCs, Kimura et al. (2004) showed that the polyamide membranes exhibited better rejection than cellulose acetate membranes. Results from investigations showed that due to electrostatic exclusion the rejection of negatively charged compounds, pharmaceuticals residues and pesticides was * Corresponding author. UNESCO-IHE, Institute for Water Education, Westvest 7, 2611AX Delft, The Netherlands. Tel.: þ31 15 215 1745; fax: þ31 15 215 2921. E-mail addresses: v.a.yangaliquintanilla@tudelft.nl, victor.yangali@gmail.com (V. Yangali-Quintanilla). Available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/watres 0043-1354/$ – see front matter ª 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.watres.2009.02.027 water research 43 (2009) 2349–2362