[Case Study] SOUTHLAKE, TEXAS Successfully Tames Disinfectant Residual Variability in Distribution Network with Mechanical Tank Mixers

Southlake, Texas is a suburb of the Dallas-Fort Worth metroplex that prides itself for possessing a quiet sophistication with ready access to the urban excitement that its location easily affords. Southlake Water Utilities has kept pace with the growing community of over 30,000 inhabitants and over 11,000 service connections while keeping a keen focus on opportunities to improve water quality to the rate payers/

As a consecutive system that purchases all its chloraminated potable water from the city of Fort Worth, Southlake has no treatment plant and therefore has limited means to actively control disinfectant residuals in its distribution network. A few years ago, Southlake operations personnel began to examine techniques to improve disinfectant residual levels throughout their system. They focused on their seven water storage tanks as places to intervene with disinfectant residual boosting. Water storage assets are ideal locations to boost residuals and reduce the risk of nitrification as they can be places of high water-age coupled with large volumes. Safety is optimized by being able to incrementally improve the disinfectant levels in tanks or reservoirs versus in-pipe boosting which can often be a “fire-and-forget” exercise with no ability to fine-tune residuals in a subsequent pressure zone.