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Table 5. Assumptions for Nitrate Loading Calculation <br />Variable Value Units Description <br />55.7 gpd Effluent flow rate <br />Nw 85 mg/L-N Effluent stream concentration <br />A 0.60 acres Site area <br />Nb 0.17 mg/L-N Concentration of rain <br />0.25 constant Denitrification factor <br />9.42 inches per year Recharge rate of rainfall <br />1.2 inches per year Uniform waste water loading (calculated) <br />The details of the nitrate loading calculation are included in Plate 13. 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 7.6 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 7.6 mg/L-N. The result of the nitrate loading <br />estimate is less than the maximum drinking water standard. <br />Discussion of Nitrate Loading Results <br />Total Nitrate Impact <br />Based on the method and assumptions described, the result of the nitrate loading <br />estimate indicates that the proposed development on the Site should not cause a <br />buildup of nitrates in the aquifer over 10 mg/L-N. Because of the favorable result of the <br />nitrate loading calculation, no nitrate mitigation is recommended at this time. <br />LOGE 2130 Page 12