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4.1 <br />4.1.1 <br />4.1.2 <br />water. The finished water quality met the EPA secondary standards for iron and manganese, as <br />well as MDH's HBV for rnanganese, for both treatment processes and filter media types. <br />Well No. 3 Results <br />Raw Water Quality <br />The pilot study for Well No. 3 was completed between January 21, 2020 and January 22, 2020. <br />Well No. 3 currently pumps approximately 1,450 gpm directly into the distribution system with <br />polyphosphate, chlorine, and fluoride added in a shared pump house with Well No. 4. Table 2 <br />below summarizes the raw water results collected from Well No. 3 during the pilot study. <br />Table 2— Weil No. 3 Raw Water Quality <br />Manganese (mg/L) <br />Min. <br />Avg. <br />Max <br />Min. <br />Avg. Max. <br />Min. <br />Avg. <br />Max. <br />0.500 <br />0.640 <br />0.850 0.160 <br />0.200 <br />0.240 7.46 7.72 7.85 <br />Results from the raw water sampling show that Well No. 3 exceeds EPA's secondary standards <br />for iron and manganese, which can cause aesthetic water quality issues related to color, taste, <br />sediment, and staining. Well No. 3 also exceeds MDH's HBV 0.1 mg/L for manganese for bottle- <br />fed infants less than one year of age. Infants who drink water with manganese above 0.1 rngiL <br />may develop learning and behavior problems. <br />Water Treatment <br />Water from Well No. 3 went through both treatment trains provided by the SEH pilot water <br />treatment plant. Train 1 utilized direct filtration through Filters 1 and 2 after chlorine and <br />potassium permanganate injection, while Train 2 utilized aeration and detention prior to filtration <br />through Filters 3 and 4. With Train 2, aeration was provided prior to chemical injection to help <br />oxidize iron, followed by chlorine and potassium permanganate injection, and then 30 minutes of <br />detention time to allow for adequate chemical reaction time before filtration. The chemical doses <br />to treat water from Well Na. 3 are provided in Table 3. All four filters in the pilot water plant were <br />operated at a rate of 3.0 gpm/ft2. <br />Table 3— Well No. 3 Chemical Dosages <br />Train 1 — Filters 1 and 2 (Direct Filtration) <br />Chlorine (ingIL as C12) <br />KMnO4 (mg/L) <br />Min. <br />Avg. <br />Max. Min. <br />Avg. ! <br />Max. <br />2.15 <br />2.92 <br />3.58 0,49 <br />1 0_49 <br />0.49 <br />MINIIIIIhrT2U— <br />6 Cn loll <br />KIVIn0.4 (mg/L) <br />Filters 3 and 4 (Mt. an <br />C12) <br />Chlorine (mg/L as <br />i <br />Min. <br />Avg. <br />Max. <br />Min. <br />Avg. <br />Max. <br />1.95 <br />3.24 <br />4.53 <br />0.10 <br />0.10 <br />L 0.10 <br />The chlorine dosages for the two treatment trains were similar, although the chlorine dosage with <br />Train 2 may be able to be reduced as aeration provides significant iron oxidation, and 30 minutes <br />PILOT STUDY REPORT <br />Page 5 <br />RAM SY 154354 <br />