AWWA WQTC56959

A pilot-scale distribution system was constructed using aged pipe materials obtained from the Tampa Bay Water member governments' distribution systems (PVC, unlined cast iron, lined iron, and galvanized). Pilot-scale treatment facilities were developed to provide finished water representing current and anticipated supplies in the Tampa Bay Water service area. After a three-month period of equilibration, different blends of the finished waters were introduced into the pilot distribution system. Water quality impacts were documented, including elevation of apparent color, iron, and turbidity. This impairment of water quality is believed to result from the release of corrosion products from the interior surface of the unlined cast iron and galvanized pipe materials. Introduction of source waters with the greatest disparity from historic groundwater sources posed the greatest potential for water quality alteration. Source water characteristics that appear to be relevant include alkalinity, chloride, conductivity, and sulfate. Experimentation is continuing with objectives to investigate mitigation measures. Includes reference, tables, figures.