Evaluation and reduction of THMs, DCAN and TCNM formation potential from chlorination and chloramination of verapamil

The yields of CF, DCAN and TCNM were increased significantly with increasing monochloramine dose. Unlike CF and DCAN, the yield of TCNM increased firstly and then deceased with contact time. The effect of pH on DBPs formation was significant both for chlorination and chloramination of VRPM. Bromide was proposed to play an important role in DBPs formation during disinfection. Compared to ultraviolet/persulfate, ultraviolet/hydrogen peroxide was a better pre-oxidation to not only efficiently oxidize VRPM, but also significantly reduce DBPs formation.