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A denitrification factor of 35 percent was selected for the Site because of the clayey soil <br /> present at the percolation test locations. <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 12. <br /> Table 5. Assumptions for Nitrate Loading Calculation <br /> Variable Value Units Description <br /> Q 386.8 gpd Effluent flow rate <br /> Nw 39.8 mg/L-N Effluent stream concentration <br /> A 3.8 acres Site area <br /> Nb 0.27 mg/L-N Concentration of rain <br /> d 0.35 constant Denitrification factor <br /> R 3.00 inches per year Recharge rate of rainfall <br /> W 1.4 inches per year Uniform waste water loading (calculated) <br /> The details of the nitrate loading calculation are included in Plate 12. The results of the <br /> calculation are presented in the following table. <br /> Table 6. Result of Nitrate Loading Calculation <br /> Variable Value Units Description <br /> Nc 8.3 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 8.3 mg/L-N. The result of the nitrate loading <br /> estimate is below the maximum drinking water standard. <br /> LOGE 20-19 Page 14 <br />