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2.)Variability in wastewater flows, nitrogen concentrations and dilution effects from stormwater <br /> recharge, 3.) Changes in groundwater directional flow and elevation, 4.)Denitrification potential <br /> within the soil environment and within the confined and/or unconfined aquifers. <br /> The Hantzsche/Finnemore Formula is used in this report to predict the average resultant <br /> concentration of nitrate-nitrogen in effluent recharge water from the proposed on-site septic system <br /> serving the restroom facilities. As calculated below,the property has been assessed on a gross <br /> developed area and not a total areal loading basis correlated with the total projected yearly <br /> wastewater flow volumes calculated above. These two factors primarily estimate the average <br /> resultant concentration of nitrate-nitrogen in the recharge water. This concentration cannot exceed <br /> 10 ppm nitrate-nitrogen(45 ppm as nitrate). <br /> Calculated nitrate-nitrogen loading from the developed area of the property: <br /> INW(1 - d)+R Nb <br /> Nr= (I +R) <br /> Where: <br /> Nr = Resultant average concentration of nitrate-nitrogen in recharge water-(ppm NO3-N) <br /> I = Volume rate of wastewater entering the soil averaged over the area in inches per yr. The subject <br /> property is 15.71 acres,but the developed area is 4.48 acres. <br /> Nw = Total nitrogen concentration of wastewater in mg N/L <br /> d = Fraction(%)of nitrate-nitrogen loss due to denitrification in the high clay content soil. <br /> R = Average recharge rate of rainfall- inches per yr. From S.J. County Isohyetal Map. NLS§3.2 <br /> Nb = Background nitrate-nitrogen concentration of rainfall recharge,exclusive of wastewater influences <br /> (ppm NO3-N)- <br /> Values and Assumptions: <br /> I=64,500 gals=total WW/yr=8,623 cu ft =0.531 in/yr <br /> 4.48 Ac x 43,560 sq ft/Ac x (1 ft/12 in) <br /> Nw=62 mg N/L <br /> d = Assume 30%due to high percentage of clay soil and high CEC in upper soil profile. <br /> R = 13 in/yr. From S.J. County Isohyetal Map. NLS§3.2 <br /> Nb= Assumed to be 0.1 ppm NO3-N <br /> 0.531 in/yr(62 mg NAL) (1 -0.30)+(13 in/yr x 0.1 mg/L) <br /> Nr = (0.531 in/yr+ 13 in/yr) <br /> Nr = 1.8 ppm as nitrate-nitrogen(NO3-N)or 8.1 ppm as nitrate (NO3) <br /> 6 �Jj <br /> Chesney Consulting <br />