To mitigate the risk of environmental contamination by microorganisms and chemical pollutants, on-site hospital wastewater and urine treatments have been recently assessed as countermeasures. In this study, we evaluated the use of advanced oxidation processes (AOPs) as a post-biological treatment method against enteric microorganism surrogates (Escherichia coli and MS2 bacteriophage) in ultrapure water (MQ) and synthetic matrices (wastewater and urine). UVC, UVC/H2O2, and UV/Fenton methods have been evaluated in terms of disinfection kinetics, in the presence and absence of Iohexol, an iodinated contrast medium. The occurrence of MS2 or E. coli notably decreased the antagonist microorganism inactivation kinetics (i.e., E. coli or MS2, respectively), whereas the addition of H2O2 always improved the disinfection performance by 20-60%. When Iohexol was present, inactivation was considerably delayed in wastewater and urine, but not in MQ, which indicated a synergistic inactivation of E. coli and MS2 with Iohexol, up to instant inactivation. Despite the abrupt effects of Iohexol on disinfection, the re-growth/survival dynamics during 3-5 days after disinfection of wastewater and urine revealed high risk of bacterial re-growth, even from low leftover counts (10 CFU/mL) but not viral re-population. Finally, simulation of hospital wastewater treatment was conducted by treating actual primary and secondary wastewater, as well as fresh urine, spiked with Iohexol. This study achieved rapid bacterial and viral inactivation, even in the presence of high amounts of Iohexol, as found in hospital effluents. Our results indicate that these methods could be applied to highly contaminated hospital environments after proper optimization of exposure time, added H2O2, and Fe amounts.