Disinfection by-products in water produced by ozonation and chlorination

Water produced by advanced treatment of a groundwater was evaluated to dete rmine the amount of DBPs (Disinfection By-Products) including trihalomethan es (THMs). Both Gas Chromatography (GC) and Gas Chromatography/Mass Spectro metry (GS/MS) were adopted for detection and identification of DBPs such as trihalomethanes (THMs), halo-acetic acids (HAAs) and aldehydes. Two disinf ection modes (ozonation followed by chlorination and chlorination alone) we re compared to determine the DBPs generation. The mutagenitic acivity of oz onated water, chlorinated water after ozonation and potable water was asses sed using the Ames test. Chloroform, dichloroacetic acid (DCAA) and trichlo roacetic acid (TCAA) were the main constituents of THMs and HAAs, respectiv ely. THMs accounted for more than 85% of all DBPs measured, whereas haloace tic acids accounted for around 14%. Ozonation followed by chlorination prov ed to be better in terms of THMs and HAAs control. The combined system prod uced 28.3% less DBPs compared to chlorination alone. Ozonation was found ca pable of reducing mutagenic matter in the groundwater by 54.7%. The combine d system also resulted in water with no mutagenicity.