Disinfection is essential for drinking water to eliminate harmful pathogens but meanwhile generates toxic disinfection byproducts (DBPs). Ferrate (Fe(VI)) is increasingly used to pre-oxidize the source water aiming at removing and modifying natural organic matter (NOM) to control the formation of DBPs in subsequent disinfection. In this study, <sup>13</sup>C nuclear magnetic resonance (NMR) spectroscopy was employed to characterize NOM, and it is the first time to report that Fe(VI) converted unsaturated aromatic functional groups in NOM to saturated aliphatic content. With high resolution mass spectrometry (HRMS) and triple quadrupole MS, it was confirmed that Fe(VI) pre-oxidation inhibited the formation of aromatic DBPs and iodo-DBPs in subsequent chlorination and chloramination, and successfully lower the cytotoxicity of disinfected waters. But meanwhile, Fe(VI) pre-oxidation increased the concentrations of haloacetic acids (HAAs), which have been regulated by the United States Environmental Protection Agency. This problem was solved by a new approach, conducting Fe(VI) oxidation after disinfection, i.e., post-oxidation. Compared with pre-oxidation, post-oxidation with Fe(VI) was more effective in controlling aromatic and unsaturated DBPs, as well as regulated HAAs, and thus decreased the cytotoxicity of disinfected drinking waters to lower levels.

Effect of ferrate oxidation on controlling halogenated disinfection byproducts (halo-DBPs) in drinking water: Pre-oxidation versus post-oxidation

ACS Spring Meeting 2021

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