Assessment of Source Water Blends on Distribution System Water Quality

摘要

A pilot-scale distribution system was constructed using aged pipe materials obtainedfrom the Tampa Bay Water member governments' distribution systems (PVC, unlinedcast iron, lined iron, and galvanized). Pilot-scale treatment facilities were developed toprovide finished water representing current and anticipated supplies in the Tampa BayWater service area. After a three-month period of equilibration, different blends of thefinished waters were introduced into the pilot distribution system. Water quality impactswere documented, including elevation of apparent color, iron, and turbidity. Thisimpairment of water quality is believed to result from the release of corrosion productsfrom the interior surface of the unlined cast iron and galvanized pipe materials.Introduction of source waters with the greatest disparity from historic groundwatersources posed the greatest potential for water quality alteration. Source watercharacteristics that appear to be relevant include alkalinity, chloride, conductivity, andsulfate. Experimentation is continuing with objectives to investigate mitigationmeasures.