The impact of coagulation on endocrine disrupting compounds, pharmaceutically active compounds and natural organic matter

Previous research indicates that pharmaceutically active compounds (PhACs) and endocrine-disrupting compounds (EDCs) are poorly removed during conventional drinking water treatment processes including coagulation; however, removal efficiency increases in the presence of natural organic matter (NOM). Therefore, this project investigates the link between various NOM types with EDC/PhAC removal. Bench-scale coagulation tests were conducted on three different source waters spiked with environmentally relevant levels (nominally 1000 ng/L) of EDCs/PhACs. Two different coagulants were used: polyaluminum chloride (PACl) and aluminum sulphate (alum). NOM was characterized using size exclusion liquid chromatography-organic carbon detection (LC-OCD).;Results for Lake Ontario, Otonabee and Grand River water indicate that certain EDCs/PhACs are significantly removed during coagulation while others increase in concentration. Concurrently, particular NOM fractions (biopolymers and humic substances) are also being removed. Solvents used for EDC/PhAC spiking (acetone and acetonitrile) did not affect coagulation, but contributed to low molecular weight neutral and hydrophobic NOM fractions.