Laserfiche WebLink
27 August 2025 AdvancedGeo <br /> Project No. 25-8011 An Employee—Owned Company <br /> Page 11 of 14 Q, X <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 /> 200 gpd (existing system) + 150 gpd (proposed system)x 365 days of proposed operation <br /> = 350 x 365 days + 7.48 gallons per cubic foot = 17,079 cubic feet of wastewater. This <br /> does not account for evapotranspiration loss that is likely to occur. <br /> NW = Total nitrogen concentration of wastewater at 35 mg/L-N based on the average <br /> discharge <br /> d = Fraction of nitrogen concentration removed from the wastewater due to denitrification <br /> within the soil (15 percent for sandy 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 /> = 127,760 gallons = 17,079 cubic feet wastewater _ [(2.42 acres x 43,560 feet2) = 12 <br /> inches] = 17,079 - 8,785 = 1.94 inches/year <br /> NW = 35 mg/L-N <br /> d = 15 percent denitrification <br /> R = 3.39 inches/year <br /> Nb = 1.0 milligram per liter <br /> Nr = [1.94 inches/year x 35 mg/L-N (1-0.15)] + (3.39 inches/year x 1.0 milligram per liter) <br /> (1.94 inches/year + 3.39 inches/year) <br /> Nr = 61.11 = 5.33 = 11.46 <br /> Nr = 11.46 ppm nitrogen (NO3_N) <br />