The City of Clearwater initiated a comprehensive plan to increase its water production capability while reducing the amount of purchased water from the regional system. This would require the City to increase the treatment of source water using membrane treatment technology. As a result of the treatment process change, the City wanted to proactively address the impact to the water distribution system. McKim & Creed executed a plan of study to address the water quality changes, determine the areas that may be impacted by the change and determine mitigation strategies to minimize customer impacts.
The study included evaluating water blending approaches, water system hydraulic modeling to address both water quality and hydraulic considerations and determine key targets for water quality characteristics of the treated water to minimize water quality impacts in the distribution system. The study included a pipe loop corrosion study. The study focused on chemical treatment requirements to mitigate corrosion of water piping and service lines in the affected area of the system as determined by hydraulic modeling. Pipe material coupons were removed from distribution piping segments and subjected to water chemistry simulations of the planned finished water from a proposed membrane treatment plant. A membrane pilot system was utilized at the treatment plant site to provide RO permeate for the corrosion loop study.
Results of the pipe loop corrosion study were utilized to determine design of bypass and blending relationships and establish post-treatment chemical treatment system requirements of water quality stabilization. The study also provided support for future water service line replacement work within the City water distribution system.