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Nitrate Mass Balance Calculation <br /> Data Input: <br /> Effluent Quantity(Q): 490 gals/day Concentration Rain (Nb): 1.00 mg/L-N <br /> Effluent Stream (NW): 45.00 mg/L-N Denitrification (d): 25.0% <br /> Site Area(A): 58.30 Acres Deep Perc. of Rain(R): 1.27 in/yr <br /> Result: <br /> Mass Balance(N j: 3.7 mg/L-N <br /> MCL Drinking Water Nitrate as N: 10.0 mg/L-N Waste Loading (W): 0.11 in/yr <br /> Percent of MCL Nitrate as N 37% <br /> Equations: <br /> (W) in = (Q) gal x 1 ft3 x 365 day x 1 acre x 12 in x 1 Find <br /> yr day 7.48 gal 1 year 43,560 ftZ 1 ft (A) acre <br /> 0.11 in/yr(site) =490 gal/day x(1 cu-ft/7.48 gals)x(365 days/1 year)x(1 acre 143,560 sq-ft)x(12 in/1 ft)x(1 site 158.3 acres) <br /> Nc= WN,,(1-d)+RN,, Hantzsche-Fennemore Equation(Nc) <br /> W+R <br /> 3.68 mg/L-N=((0.11 in/yr x 45 mg/L-N x(1-0.25))+(1.27 in/yr x 1mg/L-N))/(0.11 in/yr+1.27 in/yr) <br /> Variables: <br /> Nc=Average nitrate-N concentration (mg/1)of combined effluent and rainfall percolate(3.68 mg/L-N). <br /> W= Uniform waste water loading for study area (in/yr) (0.11 inches/year). <br /> Nw=Total nitrate-N concentration of waste water percolate (45 mg/L-N). <br /> d =Fraction of nitrate-N loss due to denitrification in the soil (25%). <br /> R= Uniform deep percolation of rainfall (1.27 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 45 mg/L-N. <br /> 2. Fraction of nitrate-N loss due to denitrification in the soil is assumed to be 25%. <br /> 3. Estimated deep percolation of rainfall is 1.27 in/yr, see deep percolation of rain worksheet. <br /> 4. Assume background nitrate-N concentration of rainfall is 1 mg/L-N. <br /> ,--44NEIL O. ANDERSON <br /> A N D A S S O C I A T E S <br /> Plate 6 <br />