Hormones and antibiotics have been recently found to be prevalent in wastewaters and surface waters at low concentrations. In this study, nanofiltration (NF) and ultrafiltration (UF) are two selected emerging technologies that may remove low levels of these compounds given varying water quality parameters such as pH and presence of natural organic matter (NOM). The natural hormone 17β-estradiol (E2) showed high levels of rejection (>75%) using NF membranes but significant levels of adsorption were observed at the initial stages of operation. Subsequent clean water addition indicated that adsorbed E2 could easily desorb, causing the membrane to act both as a sink and source. UF rejection of E2 was low but again showed significant levels of adsorption. Rejection of E2 was also enhanced by fouling of the membrane by natural organic matter (NOM), operation at higher permeate flux, and higher pH conditions. Preliminary experimental results regarding antibiotic removal indicate that NF rejection is highly pH dependent. Levels of adsorption, however, were found to vary widely on the specific antibiotic, membrane tightness, and the selected pH.
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