Ozone oxidation of bromide and natural organic matter

Ozonation of bromide containing waters results in the oxidation of bromide, a naturally occurring anion, to bromate, a suspected carcinogen. Proposed regulations by the United States Environmental Protection Agency for maximum bromate concentrations in drinking waters is 10 ;Two related, yet different, oxidation mechanisms are responsible for bromide oxidation to bromate. Both aqueous molecular ozone and HO radicals, a by-product of ozone sing other solutes. Bromide decomposition, are present during ozonation and capable of oxidizing oxidation to aqueous bromine occurs through direct molecular ozone oxidation. Aqueous bromine oxidation to bromite occurs primarily through indirect HO radical reactions. Finally, bromate formation occurs predominately through direct molecular ozone oxidation reactions with bromite. Transient aqueous bromine kinetics are presented in conjunction to bromate formation kinetics during ozonation of bromide containing waters.;Part of a novel approach, linear relationships between the moles of ozone decomposed and the moles of bromate formed exist and is defined as a bromate yield. The linear relationship signifies a constant driving force for bromate formation during ozonation.;NOM kinetically competes with bromide species for both molecular ozone and HO radicals. As a fraction of NOM, hydrophobic organic acids exert a significant ozone demand. NOM also reacts with HO radicals; the rate of reaction between hydrophobic organic acids and HO radicals span a narrow range of ;Both empirical and deterministic bromide oxidation models are presented as tools for understanding influences of water quality and water treatment variables on bromate formation. A deterministic model for ozone decomposition in the presence of NOM is also developed that illustrates the interdependency between bromate formation and ozone decomposition.