Batch ozonation experiments were conducted to investigate the effects of various operating options (i.e. additions of acid, ethanol, ammonium ion, and hydrogen peroxide) on the formation of disinfection byproducts (DBPs) in six different source waters. Formation of bromate, total organic bromines, total aldehydes (the sum of 13 aldehydes) was evaluated, assuming they represent three different types of DBPs during ozonation (i.e. inorganic bromine DBPs, organobromine DBPs, and non-brominated organic DBPs, respectively). Among the tested options, acid addition was found to be the best one to control all the three types of DBPs simultaneously on an ozone exposure basis.