Ozonation: a tool for removal of pharmaceuticals, contrast media and musk fragrances from wastewater

A pilot plant for ozonation and UV-disinfection received effluent from a German municipal sewage treatment plant (STP) to test the removal of pharmaceuticals, iodinated X-ray contrast media (ICM) and musk fragrances from municipal wastewater. In the original STP effluent, 5 antibiotics (0.34–0.63 (mu)g l1), 5 betablockers (0.18–1.7 (mu)g l1), 4 antiphlogistics (0.10–1.3 (mu)g l1), 2 lipid regulator metabolites (0.12–0.13 (mu)g l1), the antiepileptic drug carbamazepine (2.1 (mu)g l1), 4 ICM (1.1–5.2 (mu)g l1), the natural estrogen estrone (0.015 (mu)g l1) and 2 musk fragrances (0.1–0.73 (mu)g l1) were detected by LC-electrospray tandem MS and/or GC/MS/MS. ICM, derived from radiological examinations, were present with the highest concentrations (diatrizoate: 5.7 (mu)g l1, iopromide: 5.2 (mu)g l1). By applying 10–15 mg l1 ozone (contact time: 18 min), all the pharmaceuticals investigated as well as musk fragrances (HHCB, AHTN) and estrone were no longer detected. However, ICM (diatrizoate, iopamidol, iopromide and iomeprol) were still detected in appreciable concentrations. Even with a 15 mg l1 ozone dose, the ionic diatrizoate only exhibited removal efficiencies of not higher than 14%, while the non-ionic ICM were removed to a degree of higher than 80%. Advanced oxidation processes (O3/UV-low pressure mercury arc, O3/H2O2), which were non-optimized for wastewater treatment, did not lead significantly to a higher removal efficiency for the ICM than ozone alone.