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project. The following table summarizes of the assumptions for the nitrate loading <br /> calculation for the Site, as presented in Plate 18. <br /> Table 4. Assumptions for Nitrate Loading Calculation <br /> Variable Value Units Description <br /> Q 400 gpd Effluent flow rate, 4 BR + 3 BR Houses <br /> Nw 35 mg/L-N Effluent stream concentration <br /> A 1.64 acres Area <br /> Nb 0.103 mg/L-N Concentration of rain <br /> d 0.25 constant Denitrification factor <br /> R 4.39 inches per year Recharge rate of rainfall <br /> W 3.3 inches per year Uniform wastewater loading, calculated <br /> The details of the nitrate loading calculation are included in Plate 18. 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 11.3 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 nitrate in the aquifer from the use of septic <br /> systems on the Site is predicted to be 11.3 mg/L-N. <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 nitrate in the aquifer over the MCL of 10 mg/L-N. <br /> LOGE 2637 Page 13 <br />