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02 March 2023 AdvancedGeo <br /> Project No. 23-7124 An Employee-Owned Company <br /> Page 12 of 14 <br /> RESIDENTIAL: <br /> The Hantzsche / Finnemore (Nr) equation for residential home application: <br /> Nr = I x Nw (1-d) + R x Nb = (I+R) <br /> Definitions: <br /> Nr = The average concentration of nitrate-nitrogen in the recharged wastewater parts per <br /> million of nitrate-nitrogen. <br /> I = Volume rate of wastewater entering the soil averaged over the gross developed area <br /> (acres) in inches per year. The total wastewater volume for proposed project will be <br /> 900 gpd (proposed system) x 365 days of proposed operation = 900 x 365 days - 7.48 <br /> gallons per cubic foot = 43,917 cubic feet of wastewater. This does not account for <br /> evapotranspiration loss that is likely to occur. <br /> NW = Total nitrogen concentration of wastewater at 85 mg/L-N based on the average <br /> discharge of commercial waste. <br /> d = Fraction of nitrogen concentration removed from the wastewater due to denitrification <br /> within the soil (20 percent for sandy loam and loamy sand soils). <br /> R = Estimated Deep percolation / average rainfall recharge rate per year: 3.39 inches. <br /> Nb = Background nitrate-nitrogen concentration of rainfall recharge: 1.0 mg/I. The Nb is <br /> an average value determined for San Joaquin County by the EHD. <br /> EXISTING AND PROPOSED HOME CALCULATIONS: <br /> Nr = I x Nw (1-d) + R x Nb = (I+R) <br /> Assumptions: <br /> = 328,500 gallons = 43,917 cubic feet wastewater _ [(121.04 acres x 43,560 feet2) _ 12 <br /> inches] = 43,917 = 439,375 = 0.10 inches/year <br /> NW = 85 mg/L-N <br /> d = 20 percent denitrification <br /> R = 3.39 inches/year <br /> Nb = 1.0 milligram per liter <br /> Nr = [0.10 inches/year x 85 mg/L-N (1-0.20)] + (3.39 inches/year x 1.0 milligram per liter) <br /> (0.10 inches/year + 3.39 inches/year) <br /> Nr = 10.19 = 3.49 = 2.92 <br /> Nr = 2.92 ppm nitrogen (NO3_N) <br />