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Description Minimal information has been provided by the City of Roseville to analyze this treatment option. It was unknown at the time of this study if the City of Roseville’s water distribution system (watermains, booster station, storage, etc.) can supply the required fire protection and maximum day water demands for St. Anthony Village. However, enough aspects of the St. Paul Water system were evaluated to conclude that St. Paul Regional Water Services would have all of the same issues that would be experienced with Minneapolis Water, and possibly more issues such as Roseville infrastructure upgrades. Advantages and Disadvantages Similar advantages and disadvantages occur with this treatment system as does with the connection to the Minneapolis Water system. Estimated Capital and Long Term O&M Costs It is expected that the costs to purchase water from SPRWS would be as much as, if not potentially more than, the estimated cost to purchase water from the Minneapolis Water system. The capital costs required to connect to the Roseville water distribution system are anticipated to exceed the cost of connect ion to the Minneapolis Water system. 3.5 Option 5: Implement a Water Treatment System for Dioxane The fifth alternative analyzed is to remove Dioxane to below the recommended health advisory levels at the existing water treatment plant in St. Anthony Village. Description The City’s existing water treatment plant is designed to remove iron, manganese, and trichloroethylene (TCE) from the City’s three groundwater wells. Greensand filters are used to filter the iron and manganese and granular activated filters (GAC) are used to adsorb and remove the TCE. These treatment processes are not capable of removing Dioxane from the City’s water supplies. The low adsorptive capacity of D ioxane limits the effectiveness of treatment by GAC according to the United States EPA (Source – EPA Treatment Technologies for 1,4-Dioxane: Fundamentals and Field Applications). Conventional treatment methods such as air stripping and reverse osmosis are ineffective at removing Dioxane due to its low vapor pressure and high solubility. The following treatment technologies have been evaluated by the EPA at the pilot and full scale levels for D ioxane: 1) Advanced Oxidation (a) Ultra -Violet Light with Hydrogen Peroxide (b) Hydrogen Peroxide with Ozone 2) Bioremediation After careful review of the ad vantages, disadvantages, and costs for each of the above treatment processes, Ultra-Violet Light with Hydrogen Peroxide was further evaluated as the most feasible treatment option to treat Dioxane in the City’s wells. Hydrogen 1,4-DIOXANE PROJECT FEASIBILITY REPORT CITY OF ST. ANTHONY VILLAGE WSB PROJECT NO. 3183-00 PAGE 13