AWWA WQTC65850

Classical methods for the disinfection of drinking water, such as the use of chlorine and chloramines, are efficient at treating large volumes. However, some disadvantages exist such as the formation of disinfection byproducts and parasite resistance. Alternative methods for water disinfection are being used often in conjunction with chlorine to address these problems. One of these alternatives is using the solution generated from the electrolysis of brine, consisting of both the anolyte and catholyte, for the disinfection of drinking water. Although this solution consists primarily of chlorine, it likely contains numerous other oxidant species generated during the electrolysis process and is often termed a mixed-oxidant solution (MOS). Not only has MOS been shown to be more effective at the disinfection of drinking water compared to equivalent doses of chlorine, but it also has been shown to have some interesting characteristics. These include the inhibition of biofilm within the pipe system, and the inactivation of Cryptosporidium parvum, a chlorine resistant parasite. However, to date, attempts to identify what species in the MOS is responsible for the enhanced properties have been challenging and unsuccessful. The pros and cons of various methods used to identify the oxidant species in the mixed-oxidant solutions are described in this paper, including the use of quenching and trapping reagents to selectively isolate individual oxidants. Techniques examined include those for the detection of hydrogen peroxide, ozone, chlorine, and the hydroxyl radical. Advances in characterizing the chemical constituents of the mixed oxidant solutions are discussed. Includes 11 references, tables.