Removal of pharmaceuticals in water by introduction of ozonated microbubbles

Abstract Ozonated-microbubble (O 3 -MB) was applied to remove 39 pharmaceuticals in 10 therapeutic classes (ant-ivirals, anti-bacterials, anti-cancer drugs, psychotropics, anti-hypertensives, analgesic-antipyretics, contrast media, bronchodilators, anti-pruritics, and herbal medicines) in water and the results were compared with those given by O 3 alone and combined treatments with UV, and/or H 2 O 2 , or both. The summarized results clearly indicate that O 3 -MB based treatments significantly ( P 3 alone, and removal rates of >90% (>80%) were attained for 33 (37) compounds. Introduction of MB technology was indispensable to improve degradation of famciclovir (anti-viral), bicalutamide (anti-cancer), sulpiride (phychotropic) and acetaminophen glucuronide (analgesic-antipyretic) over 96.0%. Recalcitrant properties of all contrast media type compounds (iohexol, ioversol, iopromide, iomeprol and iopamidol) agains t both O 3 and O 3 -MB were significantly improved by combined treatment with UV, and removal rates became 93.8–98.8% from 0% to 52.0%, indicating effectiveness of combined use of photolysis more than oxidation by hydroxyl radicals. Combination of UV and/or H 2 O 2 with O 3 -MB increased the reaction rate constant by 2.9–5.5 times in average relative to O 3 and O 3 -MB. In addition, MB treatment improved O 3 consumption up to 2.8 times higher than the O 3 treatments. These results indicate that the combined treatments of O 3 -MB with UV and/or H 2 O 2 could minimize the environmental pollutant load of pharmaceuticals discharged into rivers. To the best of our knowledge, this is the first investigation which showed enhancement of removal rates of multiple pharmaceuticals together with combined use of UV and/or H 2 O 2 .