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Table 4. Assumptions for Nitrate Loading Calculation <br />Variable <br />Value <br />Units <br />Description <br />Q <br />250 <br />gpd <br />Effluent flow rate, 4 -bedroom house <br />Q <br />300 <br />gpd <br />Effluent flow rate, 5 -bedroom house <br />Nw <br />35 <br />mg/L-N <br />Effluent stream concentration <br />A <br />1.52 <br />acres <br />Site area <br />Nb <br />0.2 <br />mg/L-N <br />Concentration of rain <br />d <br />0.25 <br />constant <br />Denitrification factor <br />R <br />9.42 <br />inches per year <br />Recharge rate of rainfall <br />W <br />2.2 <br />Inches per year <br />Uniform waste water loading (calculated), <br />4 -bedroom house <br />W <br />2.7 <br />inches per year <br />Uniform waste water loading (calculated), <br />5 -bedroom house <br />The details of the nitrate loading calculations are included in Plates 13 and 14. The <br />results of the calculations are presented in the following table. <br />Table 5. Result of Nitrate Loading Calculation <br />Variable <br />Value <br />Units <br />Description <br />Nc <br />5.2 <br />mg/L-N <br />Long-term average concentration of percolating effluent, <br />4 -bedroom house <br />Long-term average concentration of percolating effluent, <br />Nc 5.9 mg/L-N 5 -bedroom house <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 a septic <br />systems on the Site is predicted to be 5.2 mg/L-N for a four-bedroom house or 5.9 <br />mg/L-N for a five -bedroom house. The result of the nitrate loading estimate is well <br />below the maximum drinking water standard. <br />LOGE 2103 Page 11 <br />