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Nitrate Mass Balance Calculation <br />Existing Residence <br />Data Input: <br />Effluent Quantity (Q):700 gals/day <br />Effluent Stream (Nw):35.00 mg/L-N <br />Site Area (A):2.07 Acres <br />Concentration Rain (N b):1.00 mg/L-N <br />Denitrification (d):30.0% <br />Deep Perc. of Rain (R):1.01 in/yr <br />Result: <br />Mass Balance (Nc):20.2 mg/L-N <br />MCL Drinking Water Nitrate as N:10.0 mg/L-N <br />Percent of MCL Nitrate as N 202% <br />Waste Loading (W):4.55 in/yr <br />Equations: <br />Find (W) <br />4.55 in/yr (site) =700 gal/day x (1 cu-ft / 7.48 gals ) x (365 days/ 1 year ) x (1 acre / 43,560 sq-ft) x (12 in / 1 ft) x (1 site / 2.07 acres) <br />Hantzsche-Fennemore Equation (Nc) <br />20.23 mg/L-N = ((4.55 in/yr x 35 mg/L-N x (1-0.3))+(1.01 in/yr x 1mg/L-N))/(4.55 in/yr +1.01 in/yr ) <br />Variables: <br />Nc = Average nitrate-N concentration (mg/l) of combined effluent and rainfall percolate (20.23 mg/L-N). <br />W = Uniform waste water loading for study area (in/yr) (4.55 inches/year). <br />Nw = Total nitrate-N concentration of waste water percolate (35 mg/L-N). <br />d = Fraction of nitrate-N loss due to denitrification in the soil (30%). <br />R = Uniform deep percolation of rainfall (1.01 in/yr). <br />Nb = Background nitrate-N concentration of rainfall (1 mg/L-N). <br />Assumptions: <br />1. Total nitrogen concentration of waste stream based on estimate of 35 mg/L-N. <br />2. Fraction of nitrate-N loss due to denitrification in the soil is assumed to be 30%. <br />3. Estimated deep percolation of rainfall is 1.01 in/yr, see deep percolation of rain worksheet. <br />4. Assume background nitrate-N concentration of rainfall is 1 mg/L-N. <br />Nc = WNw(1-d)+RNbW+R <br />(W) in = (Q) gal x 1 ft3 x 365 day x 1 acre x 12 in x 1 <br />yr day 7.48 gal 1 year 43,560 ft2 1 ft (A) acre