This slide presentation outlines a study on conducting a systematic investigation for gaining
insight into the formation and speciation of
haloacetic 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 direct
reaction of NH<sub>2</sub>Cl with DOM at pH 6. HOCl, the hydrolysis
product of NH<sub>2</sub>Cl, only contributes about 20% to HAA
formation, the influence of HOCl decreases with
increasing pH;
in the presence of bromide, the relative significance of
direct reactions and decomposition reactions are the same
as in the absence of bromide;
the extent of HAA formation decreased with increasing pH
for both pathways; Dichloramine (NHCl<sub>2</sub>) did not form HAA under typical
drinking water conditions; selection of a quenching agent is important in order to
obtain reliable results in kinetics experiments, the use of
NH<sub>4</sub>Cl, the quenching agent recommended by US Environmental Protection Agency
Method 552.3 for DBP samples, may create an artifact on the
HAA results, especially at short contact or reaction times; and,
lag period between Cl<sub>2</sub> and NH<sub>3</sub> addition needs to be
carefully optimized to comply with HAA regulations. Includes tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 430 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 31 |
| Published : | 06/01/2006 |
