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Table 4. Assumptions for Nitrate Loading Calculation <br /> Variable Value Units Description <br /> Q 284 gpd Effluent flow rate <br /> Nw 85 mg/L-N Effluent stream concentration <br /> A 6.44 acres Site area <br /> Nb 0.30 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 0.6 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 5. Result of Nitrate Loading Calculation <br /> Variable Value Units Description <br /> Nc 9.4 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 9.4 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 existing and proposed development on the Site should not <br /> cause a buildup of nitrates in the aquifer over 10 mg/L-N. Because of the result of the <br /> nitrate loading analysis, no nitrate mitigation is recommended at this time. <br /> LOGE 20-60 Page 14 <br />