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This slide presentation outlines a study on conducting a systematic investigation for gaininginsight into the formation and speciation ofhaloacetic acids (HAA9) during chloramination.Specifically, the study examined:HAAs formation pathways;HAA formation kinetics; and,the role of natural organic matter (NOM) characteristics in HAA formation in chloramination. Summary of important findings included: major amount (80%) of HAA is formed from the directreaction of NHsub2/subCl with DOM at pH 6. HOCl, the hydrolysisproduct of NHsub2/subCl, only contributes about 20% to HAAformation, the influence of HOCl decreases withincreasing pH;in the presence of bromide, the relative significance ofdirect reactions and decomposition reactions are the sameas in the absence of bromide;the extent of HAA formation decreased with increasing pHfor both pathways; Dichloramine (NHClsub2/sub) did not form HAA under typicaldrinking water conditions; selection of a quenching agent is important in order toobtain reliable results in kinetics experiments, the use ofNHsub4/subCl, the quenching agent recommended by US Environmental Protection AgencyMethod 552.3 for DBP samples, may create an artifact on theHAA results, especially at short contact or reaction times; and,lag period between Clsub2/sub and NHsub3/sub addition needs to becarefully optimized to comply with HAA regulations. Includes tables, figures.

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Edition: Vol. - No. Published: 06/01/2006 Number of Pages: 31File Size: 1 file , 430 KB