ABSTRACT
Ozone use in drinking water treatment is expanding as consumers demand a higher level of water quality, and this has sparked several new studies to investigate ozone disinfection by-products (DBPs). The major DBPs resulting from ozone treatment of surface or groundwaters have been identified as low molecular weight aliphatic aldehydes, in particular formaldehyde and acetaldehyde, the dialdehyde glyoxal, and the keto-aldehyde methyl glyoxal. Other partial oxidation by-products with carbonyl functionalities include glyoxylic, keto-malonic, and pyruvic acids. Hydrogen peroxide and organic peroxides have also been found in plants using ozone but appear to be removed, as are the aldehydes, by filters that possess an active biomass. Bromide, in raw waters, engages ozone in a complex cycle in which both organic bromide and inorganic bromate are end products. This paper will review a recent large-scale study of the occurrence and formation of ozone DBPs and show how studies of these by-products can be used to control their formation in finished water.
