In 2013 in Flint, Mich., as a way to reduce the city’s drinking water costs, a major decision was made to change the source water from the Detroit Water & Sewerage Department (DWSD) to the Karegnondi Water Authority (KWA). These changes can lead to elevated lead and copper scale release ( Schock & Lytle 2011, AwwaRF 1990). In addition, water chemistry can shift because of changes in source water or treatment, and multiple treatment plants or wells may exist in each system, causing zones of differing water chemistry that may vary over time and that may sometimes be difficult to define. Young children are especially sensitive to the effects of lead because their bodies are still developing and vulnerable to its neurotoxic effects.įinished water leaving a drinking water treatment plant (WTP) may meet water quality standards however, changes in the water chemistry, flow rate, and other factors can result in the release of lead from leaded plumbing materials (e.g., lead service line, leaded solder, fluxes, pipe fittings, valves, fixtures) as it passes through the distribution system. Adverse effects of ingesting lead in drinking water are well known ( Triantafyllidou et al.
Lead is a toxic metal, particularly impacting young children and infants. The lead results were consistent with levels measured from LSLs from homes in the city during sequential sampling efforts. Average lead levels across all 16 loops ranged between approximately 2 and 5 μg/L after the solenoid replacement. After the solenoids were replaced, the lead pipe rigs were successfully conditioned, and lead release with consistent influent water chemistry became relatively stable. Lead levels were relatively sporadic and statistically different during this period.
Solenoid problems resulted in sporadic and enhanced daily flow volume (but no flow rate changes) that prevented restabilization of pipe scales. The rigs were operated on a set daily on/off schedule such that a specified amount of water passed through each pipe using a solenoid valve-operated timer system. inside diameter lead pipe that were excavated from homes fed by the Flint distribution system. Each pipe rig consisted of four approximately 4 ft-long sections of 0.75 in.
The lead service line (LSL) pipe loops were constructed of polyvinyl chloride pipe and fittings and welded steel channel frames. The US Environmental Protection Agency’s Office of Research and Development designed, fabricated, and installed four pipe rigs in Flint, Mich., to help the city optimize corrosion control.
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