As part of the proposed Stage 2 Disinfectants/Disinfection
Byproducts Rule (Stage 2 D/DBPR), utilities will have to reassess the
location of samples collected for DBP compliance monitoring. This is
complicated by the various trends observed for the different classes
of DBPs in distribution systems, as well as within each class, and by
the fact that different subclasses of haloacetic acids (HAAs) are
expected to peak at different locations because of their different
chemical properties. The results described here give utilities additional
knowledge and tools to help them select their sampling locations
for DBP monitoring as part of the proposed Stage 2 D/DBPR.
To carry out the work, simulated distribution systems (annular
reactors) were placed in two parallel trains at the effluent of a fullscale
treatment plant: one train received chlorinated water and the
other chloraminated water. Each train was composed of two annular
reactors in series. The upstream annular reactor received water
with a disinfectant residual, and the downstream annular reactor
received dechlorinated or dechloraminated water. The effect of DBP
contact with biofilm formed in the absence of corrosion byproducts,
with and without a chlorine or chloramine residual, was addressed
in both cold and warm waters.
Trihalomethanes (THMs) and HAAs continued to form in the
distribution system in the presence of a free chlorine residual but
remained relatively unchanged in the presence of a chloramine
residual. In the absence of a chlorine residual, some of the HAA
species remained unchanged in cold water but were degraded in
warm water. Other HAA species showed different trends in the
absence of a disinfectant residual, but in general, concentrations
remained unchanged. In the absence of a disinfectant residual
(either free chlorine or chloramines), THM concentrations
remained relatively unchanged.
Includes 23 references, table, figures.
| Edition : | Vol. 97 - No. 2 |
| File Size : | 1
file
, 410 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 13 |
| Published : | 02/01/2005 |
