Corona Environmental Consulting assisted Denver Water in obtaining this first-of-its-kind EPA approved variance by analyzing data, creating models, and performing experimental research that substantiated Denver Water’s approach to achieving Lead and Copper Rule compliance. Denver Water began implementing the Lead Reduction Program (LRP) in 2020. The LRP is a lead management strategy that directly addresses the source of the lead with accelerated lead service line replacements, while simultaneously avoiding the long-term watershed impacts of orthophosphate addition. To address lead concerns while the lead service lines are being replaced, Denver Water is providing filters certified to remove lead to all customers with known or suspected lead service lines. To address long-term control of lead from other sources, Denver Water is increasing pH and alkalinity. The Corona team modeled the system-wide lead concentrations of LRP conditions versus orthophosphate (designated as Optimal Corrosion Control Treatment) to demonstrate equivalency between the approaches. The Equivalency Model will be used in the future to determine regulatory compliance and the success of the LRP. CEC also assisted Denver Water in experimental design and analysis of their lead pilot rack, coupon testing, and lead filter testing. Additionally, CEC developed a data-driven model to help identify lead service lines in the system and estimate the total number of lead service lines, as well as many other Tech Memos to support the variance.
For more information, visit Denver Water’s LRPP information site.