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Table 4. Assumptions for Nitrate Loading Calculation <br /> Variable Value Units Description <br /> Q 350 gpd Effluent flow rate <br /> Nw 35 mg/L-N Effluent stream concentration <br /> A 0.86 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 5.5 inches per year Uniform waste water loading (calculated) <br /> The details of the nitrate loading calculation are included in Plate 15. The result of the <br /> calculation is presented in the following table. <br /> Table 5. Result of Nitrate Loading Calculation <br /> Variable Value Units Description <br /> Nc 10.7 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 10.7 mg/L-N. The result of the nitrate loading <br /> estimate is just over 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 has the potential to cause <br /> a buildup of nitrates in the aquifer of just over 10 mg/L-N. <br /> There are several mitigating factors that should be considered, however, when <br /> evaluating whether or not the Site is likely to impact ground water with nitrate: <br /> LOGE 2118 Page 12 <br />