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Table 3. Assumptions for Nitrate Loading Calculation <br /> Variable Value Units Description <br /> Q 400 gpd Effluent flow rate, 2 houses <br /> Q 600 gpd Effluent flow rate, 3 houses <br /> Nw 35 mg/L-N Effluent stream concentration <br /> A 1.79 acres Site area <br /> Nb 0.3 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 3.0 inches per year Uniform waste water loading (calculated), 2 houses <br /> W 4.5 inches per year Uniform waste water loading (calculated), 3 houses <br /> The details of the nitrate loading calculations are included in Plates 13 and 14. The <br /> results of the calculations for two houses and three houses are presented in the <br /> following table. <br /> Table 4. Result of Nitrate Loading Calculations <br /> Variable Value Units Description <br /> Long-term average concentration of percolating effluent, <br /> Nc 11.5 mg/L-N 2 houses <br /> Long-term average concentration of percolating effluent, <br /> Nc 13.8 mg/L-N 3 houses <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 11.5 mg/L-N for two new houses and 13.8 mg/L- <br /> N for three houses. In both cases, the result of the nitrate loading estimate exceeds the <br /> maximum drinking water standard. <br /> LOGE 20-08 Page 11 <br />