Red Water Release in Drinking Water Distribution Systems

The implementation of groundwater conservation measures has forced utilities with a historical reliance on groundwater sources to consider alternative sources to augment their supplies or to eliminate their groundwater dependence. Switching from traditional source water, however, can cause unacceptable changes in water quality that result from destabilization and the release of chemical and biological films from the interior surfaces of the existing distribution systems. Data from a two-year study were used to identify significant water quality parameters and to develop a predictive nonlinear model 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 by-products in the form of red water. Temperature and hydraulic retention time were the significant physical and operational parameters identified.