Laserfiche WebLink
Table 4. Assumptions for Nitrate Loading Calculation <br />Variable <br />Value <br />Units <br />Description <br />Q <br />400 <br />gpd <br />Effluent flow rate <br />Nw <br />35 <br />mg/L-N <br />Effluent stream concentration <br />A <br />1.98 <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 />3.21 <br />inches per year <br />Recharge rate of rainfall <br />W 2.7 inches per year 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 5. Result of Nitrate Loading Calculation <br />Variable Value Units Description <br />Nc 12.1 mg/L-N Long-term average concentration of percolating effluent <br />Based on the methods and assumptions described, the use of existing and proposed <br />septic tanks and drain field systems on the Site yields a calculated buildup of nitrates in <br />the aquifer up to 12.1 mg/L-N. <br />The US EPA recommended MCL for nitrate in drinking water is 10 mg/L-N. The result <br />of the nitrate loading calculation exceeds the maximum drinking water standard. <br />Discussion of Nitrate Loadina 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 has the <br />potential to cause a buildup of nitrate in the aquifer over 10 mg/L-N. <br />LOGE 2237 Page 12 <br />