Effects of ozone and ozone/peroxide pretreatments on disinfection byproduct formation during subsequent chlorination and chloramination

► O3 reduced THM and trihalogenated HAAs precursors in waters with SUVA > 2 L mg−1 m−1. ► O3 and O3/H2O2 reduced HAN formation. ► O3/H2O2 generated more CH and HKs during chlorination than O3. ► O3 or O3/H2O2 pretreatments combined with chloramination process is favored in controlling DBPs.