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<br />the system at removing higher concentrations of Dioxane if they occurred in the City’s <br />wells in the future. <br /> <br />The removal percentages achieved from the pilot study ranged from 76.56 to 99.96 <br />percent , varying by the concentration of hydrogen peroxide added to demonstrate that a <br />full scale system could remove Dioxane from the City’s water. The Minnesota <br />Department of Health did not require any additional testing in addition to the parameters <br />that were tested in the pilot study. A copy of the pilot study report , as prepared by Trojan <br />Technologies, is included in Appendix B. A follow-up pilot study is recommended <br />during the final design phase if this option is selected. <br /> <br />The cost analysis anticipated installing t hree UVPhox units inside a new masonry or <br />precast concrete building, or WTP addition that would be constructed adjacent to the <br />existing water treatment plant. Each unit would have a treatment capacity of 1,250 gpm <br />in which two units combined could treat 2,500 gpm (capacity of two wells pumping) with <br />the third unit providing redundancy in case one unit fails or requires maintenance. <br /> <br />The new building or WTP addition would include a chemical storage room to contain a <br />5,000 gallon bulk storage tank, 100 gallon day tank, and chemical feed system for <br />feeding hydrogen peroxide. The existing effluent piping from the existing greensand <br />filters would be routed into the new building or WTP addition through a common header <br />pipe, metered, and connected to the individual treatment units. Automated control valves <br />would be used to split the flow between the unit(s) that are called for service via an <br />expanded plant automation control system (PLC/SCADA) to meet the City’s water <br />demands. <br /> <br />The treated effluent water from the treatment system would be routed back into the <br />existing pipe gallery of the GAC filter building where the excess hydrogen peroxide <br />would be quenched and removed by the GAC filters. The estimated time to implement <br />this option is approximately two years. <br /> <br />Figure 2 shows the location where a full scale UV light and hydrogen peroxide treatment <br />system could be implemented in the City’s existing treatment process. <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br />1,4-DIOXANE PROJECT <br />FEASIBILITY REPORT <br />CITY OF ST. ANTHONY VILLAGE <br />WSB PROJECT NO. 3183-00 PAGE 15