When the number of OH-radicals in a solution rises, one speaks of an Advanced Oxidation Process (AOP). This unique process causes dissolved solids to be oxidized by both ozone (direct) and OH-radicals (indirect). The ozone oxidation process is represented scematically in figure 1.
Read more: http://www.lenntech.com/library/ozone/reaction/ozone-reaction-mechanisms.htm#ixzz4MgGIdssQ