Until recently, drinking water suppliers have emphasized the
use of sophisticated techniques at the treatment plant to
ensure good water quality. Such an approach, however,
may be risky if water quality significantly deteriorates in the
distribution system. This study tracked the fate of chlorine dioxide
(ClO2) and its major inorganic by-products, chlorite and
chlorate ions (ClO2- and ClO3-),
in a full-scale distribution
system.
In a network fed by a treatment plant using ClO2 in postdisinfection,
ClO2- concentrations decreased with increasing water
residence time, most likely because of the ion's chemical instability
and reactions with the pipe material's ferrous ion. In the two
networks fed by plants using free chlorine in postdisinfection,
ClO2- levels were below the method detection limit (MDL). ClO3-
concentrations in the first network were either below the MDL or
stable at low levels in cold water and decreased slightly with
increasing residence time in warm water. ClO3- levels in the other
two networks showed significant variations, some of which may
be attributable to microbial biomass.
Increasingly stringent regulations under the Disinfectants/Disinfection
Byproducts Rule are forcing water suppliers to reconsider
their use of chlorine. This study's findings should help drinking
water providers more accurately assess the feasibility of using
ClO2 as an alternative disinfectant. Includes 83 references, table, figure.
| Edition : | Vol. 94 - No. 7 |
| File Size : | 1
file
, 220 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 10 |
| Published : | 07/01/2002 |
