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0.5 <br />0.4 <br />M <br />0.0 <br />09/22/21 <br />09/29/21 10/06/21 10/ 13/21 10/21 /21 10/28/21 11 /04/21 11 /11 /21 <br />Date (mm/dd/yy) <br />11 /19/21 <br />X Raw Influent ♦ Filter 1 Effluent ❑ Filter 2 Effluent Effluent Target Conc. <br />Figure 5-3. Biological Manganese Removal <br />Similar to the iron removal results, the manganese removed by the filters increased significantly during the <br />treatment efficiency phase when compared to the acclimation phase. Filter 1 performed significantly better <br />during the acclimation phase, but Filter 2 ended up removing slightly more manganese than Filter 1 towards <br />the end of the study. Table 5-3 below summarizes the average manganese removed by the filters during <br />both phases of the study. <br />Table 5-3. Manganese Removal Efficiency <br />Phase <br />Avg. Manganese Removal <br />Filter 1 <br />Filter 2 <br />Acclimation <br />43% <br />26% <br />Treatment Efficiency <br />91 % <br />95% <br />5.4 Ammonia Removal <br />The ammonia removal results obtained in this pilot study are shown in Figure 5-4. The figure below shows <br />the raw water ammonia concentration, the effluent ammonia concentration (Filter 1 and Filter 2), and the <br />effluent target ammonia concentration. The filters' effluent ammonia concentrations were almost identical <br />towards the end of the study and all effluent ammonia concentrations during the treatment efficiency phase <br />were below the target effluent concentration of 0.10 mg/L. It should be noted that the raw water ammonia <br />concentration in Well 6 was higher than expected when compared to the water quality testing completed in <br />2020 as part of the City's Water Treatment Plant Feasibility Study (see Table 2-1 for the 2020 sampling <br />results). <br />Water Treatment Pilot Study Report <br />Biological Removal of Ammonia, Iron and Manganese at Well House No. 6 <br />City of Lino Lakes, MN <br />WSB Project No. 0 18601 -000 Page 9 <br />