Bromide and Prechlorination Effects upon Disinfection Byproduct Formation within a Chlorine/Chloramine Disinfection Approach
氯/氯胺消毒方法中溴化物和预氯化对消毒副产物形成的影响
Short-term disinfection byproduct (DBP) formation was impacted by bromide when the water was in contact with
chlorine for times less than 4 hours. An increase in the bromide:total organic carbon (TOC) ratio resulted in an increase
of the percentage of brominated Trihalomethanes (THMs) and Haloacetic Acids (HAAs). However, the rate of TTHM kinetics (mass
and molar basis) were similar within the short-term, despite increasing the bromide:TOC ratio
for a given water. The dihaloacetic acids (DHAAs) and trihaloacetic acids (THAA) short-term kinetic rates were different, where DHAAs
exhibited faster kinetics for times less than 1 hour. Also, bromine's greater halogenation
efficiency and bromine's influence upon the mass yield (higher molecular weight) led to the
formation of significant amounts of brominated species on a mass basis within the short-term.
DHAAs were formed due to chloramines, but the prechlorine reaction consumed very fast-reacting
(5 minutes) DHAA precursors, which would otherwise be formed if chloramines were
only used. For one water some of the slow-reacting (5-20 days) DHAA precursors were
consumed in the prechlorine reaction, whereas for the other two waters the long-term yields and
kinetics did not differ for prechlorinated and nonprechlorinated natural organic matter (NOM). Includes 12 references, tables, figures.