||Chlorine Utilization during Trihalomethane Formation in the Presence of Ammonia and Bromide.
Amy, G. L. ;
Chadik, P. A. ;
King, P. H. ;
Cooper, W. J. ;
||Arizona Univ., Tucson. Dept. of Civil Engineering and Engineering Mechanics. ;Florida International Univ., Miami. Drinking Water Research Center.;Environmental Protection Agency, Cincinnati, OH. Water Engineering Research Lab.
||EPA-R-809935-01 ;EPA-R-810277-01; EPA/600/J-84/388;
Chemical reactions ;
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The paper describes the chlorination of humic substances in the presence of ammonia and bromide and the resultant formation of trihalomethanes (THMs). Both natural and synthetic waters were studied to isolate the singular and composite effects of ammonia and bromide on the THM formation reaction. Breakpoint chlorination, as well as kinetic experiments, was run for each water. For each breakpoint experiment, measured chlorine demands were compared against theoretical estimates of chlorine utilization on the basis of an assumed set of reactions involving chlorine reacting with ammonia, bromide, and humic substances. The presence of ammonia was found to significantly reduce but not eliminate THM formation at applied chlorine concentrations of less than the breakpoint concentration. Above the breakpoint concentration, THM formation markedly increased in response to the presence of a free chlorine residual. The presence of bromide was found to increase THM yield in the presence or absence of ammonia.