Discharging various micropollutants into aquatic environment, in particular substances classified as priority and hazardous ones, leads to serious concerns due to their potential adverse effects on human health and living organisms. Their effective removal requires novel processes. Ozone based processes are considered to be very promising. Results on ozonation, adsorptive ozonation and combined process of ozone with zero-valent iron nanoparticles are presented. Five selected organochlorine pesticides were used as organic contaminants in model water. High removal efficiencies of ozonation, except for lindane and hexachlorobutadiene, were observed. Even higher removal rates and efficiencies were measured using the O-3/UV process. However, the low removal efficiencies obtained for lindane and hexachlorbutadiene have not been explained. Adsorptive O-3/GAC and O-3/ZEO ozonation processes also provided high removal rates and efficiencies, but again, except for lindane. Significant reduction of the reaction time resulted from these processes. Very low removal efficiencies measured for hexachlorobenzene and hexachlorbutadiene with nZVI, were solved using the O-3/nZVI process. Moreover, the O-3/nZVI process is characterized by a significant reduction of the reaction time when compared with the ozonation processes. The results suggest that nZVI and O-3/nZVI processes have the highest potential to intensify the degradation and removal of organochlorine pollutants. (C) 2015 Elsevier B.V. All rights reserved.