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FrEvapotranspiration <br /> n capabilities of the indigenous clayey surface soils and the fine-grained subsurface <br /> cted to increase and substantiate the denitrification potential. Ammonium retention <br /> ils should also be significant, as has been observed in other projects with similar soils. <br /> iration has not been factored in any of the three nitrate loading methods; however, it <br /> ificant part of wastewater management and consequently nitrate-nitrogen loading. <br /> Hantzsche/Pinnemore Equation <br /> IN(1 - d) +RNh <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 gross developed area in <br /> inches per yr. Total wastewater volume: 2,475 gpd x 365 days/year=903,375 gals+7.47 <br /> gals per ft' = 120,772 cu ft of wastewater. <br /> Does not account for Evapotranspiration. <br /> Nw= Total nitrogen concentration of wastewater at 87 mg N/L based on average of three effluent samples. <br /> Does not account for loss of nitrogen in septic tanks (15%+) or through biomat(10%+). <br /> d = Fraction (%) of nitrate-nitrogen loss due to denitrification in the soil <br /> R = Average recharge rate of rainfall - inches per yr <br /> Nb= Background nitrate-nitrogen concentration of rainfall recharge, exclusive of wastewater <br /> influences (ppm NO3-N) <br /> Values and Assi=tions <br /> I= 903.375 eals =total WW/Yr= 120.772 cu ft/vr= 1.66 in/yr <br /> 20 Ac x 43,560 sq ft/Ac x (1 ft/12 in) <br /> Nw= 87 mg N/L <br /> d = Assume 25% due to a fine-grained silt and clay soil at soil/effluent interface. <br /> R = 13.2 in/yr. <br /> Nb= Assumed to be 0.1 ppm N0;N <br /> 1.66 in/,g(87 mg N/L) (1 - 0.25) + (13.2 in/yr x 0.1 me/L) <br /> Nr = (1.66 in/yr+ 13.2 in/yr) <br /> Nr = 7.4 ppm as nitrate-nitrogen (NO3-N) or 32.9 ppm as nitrate (NO3) <br /> Nr under the Maximum Contaminant Level(MCL) for nitrate-nitrogen at 10 ppm. <br /> LL�_ <br /> Page-17 �Ji <br /> - <br /> Chesney Consulting <br />