Sustainable removal of iodinated X-ray contrast media (XRC) by ozonation in a complex wastewater matrix--urine as example.

Pharmaceutical and diagnostic substances like antibiotics, cytostatics and iodised X-ray contrast media (XRC) are well-known for not being metabolised and are excreted soon after application. As a result, these preparations are difficult to biodegrade and their adsorption behaviour is rather poor. Finally, the refractory properties of these substances are leading to an accumulation in the natural waterbody depending on the hydrological situation. The elimination of contrast media from urine and diluted urine solutions by ozonation was investigated using a bubble column reactor to remove and recover the formed elemental iodine from the solution by gas stripping and down stream absorption. The experiments showed that the destruction of XRCs from concentrated solutions like urine is feasible and a recycling of elemental iodine from the exhaust gas is technically and economically possible.