Ozonation, a viable option for improving wastewater effluent quality, requires process optimization to ensure theorganic micropollutants (OMPs) elimination and disinfection under minimized byproduct formation. This studyassessed and compared the efficiencies of ozonation (O3) and ozone with hydrogen peroxide (O3/H2O2) for 70OMPs elimination, inactivation of three bacteria and three viruses, and formation of bromate and biodegradableorganics during the bench-scale O3 and O3/H2O2 treatment of municipal wastewater effluent. 39 OMPs werefully eliminated, and 22 OMPs were considerably eliminated (54 ± 14%) at an ozone dosage of 0.5 gO3/gDOCfor their high reactivity to ozone or ?OH. The chemical kinetics approach accurately predicted the OMP elimination levels based on the rate constants and exposures of ozone and ?OH, where the quantum chemicalcalculation and group contribution method successfully predicted the ozone and ?OH rate constants, respectively.Microbial inactivation levels increased with increasing ozone dosage up to ~3.1 (bacteria) and ~2.6 (virus) log10reductions at 0.7 gO3/gDOC. O3/H2O2 minimized bromate formation but significantly decreased bacteria/virusinactivation, whereas its impact on OMP elimination was insignificant. Ozonation produced biodegradable