Tideflex® Mixing System (TMS) Achieves Complete Mixing and Resists Freezing
Challenge
Planners for the city of Carlisle, PA, needed to replace buried rectangular water reservoirs and their floating covers with new above ground tanks. A mixing system was needed for the tanks that would be reliable, cost effective and resistant to freezing.
Solution
Treatment plant staff and consulting engineers turned to the engineers at Tideflex Technologies for a custom-designed solution. A Tideflex Mixing System® (TMS) was selected because it eliminates short-circuiting and water stagnation and achieves complete mixing in water tanks. Red Valve engineers designed a maintenance-free, single multiport manifold comprised of variable orifice Tideflex® Inlet Nozzles and Waterflex Outlet Check Valves that would produce rapid and complete mixing to improve water quality. The TMS requires no additional energy source beyond the flow of water into the tank during the filling process. This provides an energy cost savings to the borough when compared to other active tank mixing alternatives that may have been selected.
Results
The TMS was installed in the reservoir tanks. A pump station pulls water out of the tanks where free chlorine is added prior to it entering the distribution system. Chlorine analyzers are utilized at the pump station as a part of the borough’s quality control monitoring program. When the town had buried tanks, residual loss was a common problem. Now with the TMS, chlorine residuals are elevated and very stable. The borough water treatment plant manager stated, “I have been able to trim back chlorine dosing,” providing an additional cost-savings to the borough.
Always striving to maintain the highest quality water, the treatment plant operates their system to maximize tank volume turnover, which will minimize water age. The tank operating ranges stay relatively constant throughout the year, and do not fluctuate more than 9’.
Record-breaking cold air broke low temperature records across the United States in the winter of 2014, where temperatures fell to unprecedented levels during a polar vortex. After the region experienced sustained cold for 5-6 days, an operator working with the water treatment plant went to the top of one of their tanks, where the TMS was installed, to check on the condition of the tank. The operator said that there was, “Absolutely no icing.”