With the implementation of groundwater conservation
measures, many utilities with a historical reliance
on groundwater sources have been obligated to consider
alternative sources to augment their supplies or
eliminate their groundwater dependence. Switching
from traditional source water, however, can bring
about unacceptable changes in water quality resulting
from destabilization and release of chemical and biological
films from the interior surfaces of the existing
distribution systems. For example, red water release in
distribution systems is caused by the release of corrosion
products from unlined- and galvanized-iron pipes.
In this two-year study, the effect of changing water
quality on red water release in distribution systems
was evaluated under a wide range of conditions to
simulate blending of different source waters (groundwater,
surface water, and desalinated water). First,
investigators identified alkalinity, chlorides, sulfates,
sodium, dissolved oxygen, temperature, and hydraulic
retention time (HRT) as significant water quality parameters.
Next, a predictive nonlinear model was developed
to estimate the corrosivity of blends based on
water quality.
The results of the statistical analysis indicate that
alkalinity, chlorides, sulfates, sodium, and dissolved
oxygen of the source water or blend of source waters
have a significant effect on release of corrosion byproducts
in the form of red water. Alkalinity has a
strong negative correlation to increase in color, but
chlorides, sulfates, sodium, dissolved oxygen, temperature,
and HRT showed a positive correlation to
increase in color. Temperature and HRT were the significant
physical and operational parameters identified.
This work resulted in a valuable tool for evaluating
release problems resulting from different blends
of water. Includes 13 references, tables, figures.
| Edition : | Vol. 97 - No. 9 |
| File Size : | 1
file
, 230 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 8 |
| Published : | 09/01/2005 |
