AWWA WQTC69243

This paper presents the results from the first U.S. pilot study of the ACTIFLO® Turbo technology. The pilot was conducted with the assistance of the Town of Louisburg, North Carolina from May through August 2008. The ACTIFLO® Turbo pilot unit consists of a 200 gpm (756 lpm) capacity ACTIFLO® Turbo tank system, with coagulation, maturation, and settling tanks. The maturation tank is equipped with a Turbomix stainless steel draft tube and mixer, which provides a condensed mixing zone for enhanced flocculation. The inclusion of the Turbomix allows for the following design improvements: reduced retention times, by as much as 50% in the coagulation tank and 50% in the maturation tank, as opposed to the conventional ACTIFLO® parameters; the elimination of the injection tank and mixer from the design; operation at a settling tank overflow rate of 32 gpm/sq. ft. (80 m/hr) and greater, instead of the typical design rate for conventional ACTIFLO® drinking water designs; and, reduced total system retention time of approximately 7 minutes or less. This technology has been evaluated on a pilot scale at the Louisburg Drinking Water Plant over a period of 8 weeks. The data from the Louisburg trials shows the ACTIFLO® Turbo system's ability to produce effluent water turbidities of < 1 NTU at settling tank overflow rates of up to 50 gpm/sq. ft. (120 m/hr). Coagulant and polymer feed rates remained consistent with prior conventional ACTIFLO® pilots conducted on similar source waters. The Louisburg pilot demonstrates the ACTIFLO® Turbo system's ability to produce excellent settled water quality in a greatly reduced footprint. Includes 5 references, tables, figures.