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A denitrification factor of 35 percent was selected for the Site because of the clayey soil <br /> strata present at the percolation test location. <br /> Nitrate Loading Estimate <br /> A nitrate loading scenario was employed to determine the impact from the proposed <br /> project to ground water. The scenario utilizes the variables discussed previously, which <br /> represent the estimated conditions and uses associated with this project. The following <br /> table presents a summary of the assumptions for the nitrate loading calculation for the <br /> Site, as presented in Plate 7. <br /> Table 3. Assumptions for Nitrate Loading Calculation <br /> Variable Value Units Description <br /> 0 1,050 gpd Effluent flow rate <br /> Nw 35 mg/L-N Effluent stream concentration <br /> A 4.83 acres Site area <br /> Nb 0.17 mg/L-N Concentration of rain <br /> d 0.35 constant Denitrification factor <br /> R 6.24 inches per year Recharge rate of rainfall <br /> W 2.9 inches per year Uniform waste water loading (calculated) <br /> The details of the nitrate loading calculation are included in Plate 7. The results of the <br /> calculation are presented in the following table. <br /> Table 4. Result of Nitrate Loading Calculation <br /> Variable Value Units Description <br /> Nc 7.4 mg/L-N Long-term average concentration of percolating effluent <br /> The US EPA recommended MCL for nitrate in drinking water is 10 mg/L-N. In a worst- <br /> case situation, the maximum buildup of nitrates in the aquifer from the use of septic <br /> systems on the Site is predicted to be 7.4 mg/L-N, below the maximum drinking water <br /> standard. <br /> LOGE 2119 Page 9 <br />