This powerpoint presentation begins by providing a brief overview of disinfection byproduct (DBP) formation. Study objectives were to: investigate the roles of pH, bromide and nitrite
concentrations on the formation and speciation of Halonitromethanes
(HNMs) under Uniform Formation Conditions (UFC) for
different oxidation/disinfection scenarios -
chlorination,
chloramination,
ozonation,
ozonation-chlorination, and
ozonation-chloramination
typically used during drinking water treatment; and, to
compare side by side trihalomethane (THM) and HNM formations. Study approach and analytical methods are presented. Study conclusions for HNM precursors indicate that:
the major precursors of HNMs and THMs are not the same in
natural waters;
conventional treatment removes THM precursors but not very
effective in removing HNM precursors; and,
hydrophilic natural organic matter (NOM) components in natural waters are the major
HNM precursors. Study conclusions for Bromide, nitrite, and pH effects indicate that:
during chlorination, bromide effect on HNM formation was not
apparent;
during ozonation-chlorination, increase in bromide
concentration increased HNM formation significantly; and,
in the presence of high bromide levels, the speciation of HNMs
will shift from chlorinated HNMs towards brominated species; the presence of nitrite significantly increases HNM
concentrations during chlorination and ozonation-chlorination; and,
HNM formation increased with pH. Study conclusions for disinfectant effects indicate that:
at typical drinking water treatment conditions, HNM formation will
be the most problematic using ozonation-chlorination; and,
one way to minimize HNM formation in the ozonation plants is to
use chloramination for post disinfection, or practice biofiltration. Includes tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 1.1 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 21 |
| Published : | 11/01/2009 |
