AWWA MTC64596

The adsorption of twenty-two endocrine disrupting compounds (EDCs) and pharmaceutically active compounds (PhACs) to ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) membranes was investigated using 24-hour bottle tests. Two natural waters (Lake Ontario water and effluent from a membrane bioreactor (MBR)) and one laboratory-grade water (Milli-Q® water) were examined in order to determine the influence of organic matter on compound adsorption to membranes. Adsorption was most influenced by compound log K_ow, a measure of hydrophobicity, and water solubility. Hydrophobic adsorption appears to be the main mechanism responsible for EDC and PhAC adsorption. Adsorption was highest with the UF membrane followed by the NF and RO membranes. Adsorption was also affected by membrane pure water permeability (PWP), which gives an indication of the porosity of a membrane. It is proposed that a more porous membrane provides a larger surface area which results in more available membrane adsorption sites. Finally, in order to avoid masking the influence of water matrix on adsorption due to differences in analytical sample recoveries, it was determined that the use of compounds with surrogates would provide the most accurate investigation of the influence of water matrix on adsorption. Includes 30 references, tables, figures.