Feasibility of nanofiltration for the removal of endocrine disrupting compounds

Surface water can contain significant amounts of endocrine disrupting compounds (EDCs) originating mainly from effluent of households, sewage treatment plants and farming activities. In this work the feasibility of nanofiltration for the removal of EDCs is evaluated. Estradiol retentions of. respectively, 75% (UTC-20) and 85% (NF270) and estrone retention of 83% (UTC-20) and 65% (NF270) were obtained. These retentions were lower than expected based on the MWCO and also lower than the retention of salicine, with a comparable molecular weight but more hydrophilic. However, the differences in retention between estrone, estradiol and salicine are less than those between Compounds with a molecular weight below the MWCO of both membranes. This results from a decreasing influence of hydrophobicity on retention as the molecular size increases compared to the MWCO. An economical evaluation based on the obtained results showed that the implementation of nanofiltration in the drinking water process is not economically feasible for year capacities of 3.5 and 4.5 Mm(3)/year and peak factors of 1.3 or 1.4 using a water price of 0.50 (sic)/m(3). This price should be more than double in order to obtain a NPV of zero at an interest of 10% over a period of 10 years. Finally, it was found that a 50% decrease of membrane prices has barely an influence on the installation costs as pay back time and NPV value were nearly the same for the different alternatives.