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ENVIRONMENTAL TECHNOLOGY VERIFICATION JOINT (NSF-EPA) VERIFICATION STATEMENT AND REPORT, PERFORMANCE OF INDUCTION MIXERS FOR DISINFECTION OF WET WEATHER FLOWS, US FILTER/STRANCO PRODUCTS WATER CHAMP R F SERIES CHEMICAL INDUCTION SYSTEM
Citation:
Alden Research Laboratory, Inc., AND Moffa & Associates. ENVIRONMENTAL TECHNOLOGY VERIFICATION JOINT (NSF-EPA) VERIFICATION STATEMENT AND REPORT, PERFORMANCE OF INDUCTION MIXERS FOR DISINFECTION OF WET WEATHER FLOWS, US FILTER/STRANCO PRODUCTS WATER CHAMP R F SERIES CHEMICAL INDUCTION SYSTEM. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-02/064.
Description:
The Wet-Weather Flow Technologies Pilot of the EPA's Technology Verification (ETV) Program under a partnership with NSF International has verified the performawnce of the USFilter/Stranco Products chemical induction mixer used for disinfection of wet-weather flows. The USFilter tested a series of chemical induction mixers (5-, 10- and 20-horsepower) at the hydraulic laboratory facilities of United States Geological Survey's Conte Anadromous Fish Research Center, Turners Falls, MA. Each induction mixer was tested separately in a rectangular flume, incorporating a channel section 7 feet wide with a water depth of 7 feet at nominal flow velocities of 0.5 feet/second, 1.25 feet/second, and 3.0 feet/second. Rhodamine WT tracer dye was used as a surrogate for the chemical disinfectant. A sampling rig was positioned at locations 5 feet, 10 feet, and 15 feet downstream of the mixer to collect dye samples over the entire cross section of the flume to characterize the size and nature of the "chemical " plume. From the data generated during verification testing it was possible to determine (calculate) the sizing guidance (power-to-volume ratio) for the induction mixers. These data indicated that a mixer sizing criteria of between 0.22 and 0.31 HP/MGD resulted in mixing sufficient for disinfection in the 7 ft x 7 ft opern channel applications with flow velocities between 0.5 and 3.0 ft/s. The data also indicated a break point in the data at a flow velocity of 1.25 ft/s, where at higher velocities that flow velocity significantly influenced the ability of the mixer to effectively disperse tracer. Therefore, expected range of flow velocities must be considered when selecting an appropriate sized mixer during the design of open channel mixing facilities.