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A standard denitrification factor of 25 percent (Hantzsche and Finnemore, 1992) was <br />selected for the Site based on the sandy silt soil present at the percolation test location. <br />Nitrate Loadina Estimate <br />A nitrate loading scenario was employed to determine the impact from the proposed <br />project to ground water. The scenario utilizes the variables discussed previously, which <br />represent the estimated conditions and uses associated with this project. The following <br />table presents a summary of the assumptions for the nitrate loading calculation for the <br />Site, as presented in Plate 14. <br />Table 5. Assumptions for Nitrate Loading Calculation <br />Variable Value Units Description <br />Q <br />167.8 <br />gpd <br />Effluent flow rate <br />Nw <br />85 <br />mg/L-N <br />Effluent stream concentration <br />A <br />14.70 <br />acres <br />Site area <br />Nb <br />0.136 <br />mg/L-N <br />Concentration of rain <br />d <br />0.25 <br />constant <br />Denitrification factor <br />R <br />8.41 <br />inches per year <br />Recharge rate of rainfall <br />W <br />0.2 <br />inches per year <br />Uniform waste water loading (calculated) <br />The details of the nitrate loading calculation are included in Plate 14. The result of the <br />calculation is presented in the following table. <br />Table 6. Result of Nitrate Loading Calculation <br />Variable Value Units Description <br />Nc 1.3 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 nitrates in the aquifer from the use of septic <br />systems on the Site is predicted to be 1.3 mg/L-N. The result of the nitrate loading <br />estimate is well below the maximum drinking water standard. <br />LOGE 2221 Page 12 <br />