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01 April 2021 AdvancedGeo <br /> Project No. 21-6365 AnEmployee-Owned Company <br /> Page 13 of 15 ^ <br /> denitrify the concentrations by approximately 30 percent and less desirable soils with <br /> more sands and faster percolation rates (less moisture and clay content) denitrify only <br /> about 10 percent. <br /> A denitrification factor of 30 percent was selected for the calculation based on the clay <br /> and loam soil existing at the site. <br /> 9.6. MASS BALANCE OF NITROGEN LOADING <br /> The EHD requires the user to consider all potential sources identified for wastewater <br /> generation. Further, the EHD supports the use of Hantzsche/Finnemore, or other <br /> appropriate formula/model to calculate a mass of nitrogen loading. <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 /> 150 gpd (existing system) + 150 gpd (proposed system)x 365 days of proposed operation <br /> = 300 x 365 days _ 7.48 gallons per cubic foot = 14,639 cubic feet of wastewater. Does <br /> not account for evapotranspiration likely to occur. <br /> NW = Total nitrogen concentration of wastewater at 45 mg/L-N based on the average <br /> discharge. Accounting for the loss of mg/L-N in the septic tank at 15% = 45-15%= 38.25 <br /> and the loss from the biomat at 10% 38.25 - 10% = 34.425 mg/L-N. <br /> d = Fraction of nitrogen concentration removed from the wastewater due to denitrification <br /> within the soil (30 percent for clay and loamy soils). <br /> R = Estimated Deep percolation / average rainfall recharge rate per year: 3.05 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 = IxNw (1-d) + RxNb = (I+R) <br />