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Nitrate Mass Balance Calculation: Engineered Septic System <br /> Data Input: <br /> Effluent Quantity (Q): 2,714 gals/day Concentration R W (Nb): 0.17 mg/L-N <br /> Effluent Stream (N,): 17.00 mg/L-N Denitrification(d): 35.0% <br /> Waste Loading (W). 10.42 in/yr Deep Perc. of Rain (R): 5.01 in/yr <br /> Site Area (A): 3.5 Acres <br /> Result: <br /> z Mass Balance(N j: 7.5 mg/L-N <br /> MCL Drinking Water Nitrate as N: 10.0 mg/L-N <br /> Percent of MCL Nitrate as N 75% <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 qal 1 year 43,560 ft2 1 ft (A) <br /> 10.42 in/yr(site) =2,714 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/3.5 acres) <br /> N, = WN-0-d)+RN,, Hantzsche-Fennemore Equation (Nc) <br /> ,WN <br /> 7.52 mg/L-N=((10.42 in/yr x 17 mg/L-N x(1-0.35))+(5.01 in/yr x 0.17mg&-ivy) 10.42 in/yr+5.01 in/Srr) ,� <br /> Variables: <br /> Nc=Average nitrate-N concentration (mg/1)of combined effluent and rainfall percolate (7.52 mg/L-N). <br /> W= Uniform waste water loading for study area (in/yr) (10.42 inches/year). <br /> Nw=Total nitrate-N concentration of waste water percolate (17 mg/L-N). <br /> d = Fraction of nitrate-N loss due to denitrification in the soil (35%). <br /> R = Uniform deep percolation of rainfall (5.01 in/yr). <br /> Nb= Background nitrate-N concentration of rainfall (0.17 mg/L-N). <br /> Assumptions: <br /> 1. Nitrate-N concentration of waste stream based on estimate of 17 mg/L-N. <br /> Assumption based on work from Hantzsche and Finnemore, 1992. <br /> 2. Fraction of nitrate-N loss due to denitrification in the soil is assumed to be 35%. <br /> Assumption based on work from Hantzsche and Finnemore, 1992. <br /> 3. Estimated deep percolation of rainfall is 5.01 in/yr, see deep percolation of rain worksheet. <br /> 4. Assume background nitrate-N concentration of rainfall is 0.17 mg/L-N based on range by <br /> Hantzsche and Fennemore, 1992. <br /> ptRJ 1 <br /> NEIL O.ANDERSON&ASSOC.,INC. <br /> OE OIE CN NCAL SERVICES ENGIN EERNG LABORATORIES Z r <br /> 22 Nouslon Ln.L.dl,CA 85240 O '\ <br /> 120BI3874701 <br /> Jso� <br /> Plate 10 <br />