AWWA WQTC71507

This powerpoint presentation begins by providing a brief overview of the Valley County Water District's four treatment processes. Options to remove or prevent calcification are presented and include: upstream acid addition; in-situ cleaning; antiscalants; and, packing material replacement. Presentation conclusions indicate the following: periodic in-situ cleanings of packing material appeared to be the most cost-effective option; however, a cleaning conducted this year was not completely effective; antiscalants offer an economical solution with minimal impact observed on perchlorate resins in terms of capacity or fouling; upstream acid addition may minimize calcium carbonate precipitation but is cost-prohibitive and requires downstream acid addition due to pH increases in the aeration towers; and, packing material replacement is an option but is costly and results in significant downtime. Includes tables, figures.