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FANitrate <br /> ATE-NITROGEN IMPACT AND MITIGATION <br /> Loading Mass Balance <br /> g mass balance calculation is illustrated below for the current status of the subject <br /> property. The calculated or estimated nitrate impact to the soil and ultimately to the groundwater <br /> is extremely difficult to determine due to the number of variables involved. The Hantzsche/ <br /> Finnemore Equation is used below to estimat uu t average nitrate-nitrogen concentration <br /> in the effluent recharge water. A volume bf 500 gpd, and a Total Nitrogen concentration of 112 <br /> ppm has been used in the calculations. This 112 ppm concentration was derived from septic tank <br /> effluent analysis from other similar-type projects. <br /> The second Hantzsche/Finnemore Equation calculations on Page 7 demonstrate the theoretical <br /> number of people the entire subject property(179-160-18, 19 and 20) can support without <br /> exceeding the Maximum Contaminant Level for nitrate in drinking water(10 ppm as nitrate- <br /> nitrogen). The third Hantzsche/Finnemore Equation on Page 8 illustrate the theoretical number <br /> of people for APN 179-160-20 (4 acres), exclusively. <br /> HANTZSCHEIFINNEMORE EQUATION <br /> IN O -d)+RNb <br /> Nr= (I+R) <br /> Where: <br /> Nr= Resultant average concentration of nitrate-nitrogen in recharge water-(ppm NO,-N) <br /> I = Volume rate of wastewater entering the soil averaged over the gross developed area in inches per yr <br /> Nw= Total nitrogen concentration of wastewater in N mg/L(112 mg N/L/day) <br /> d = Fraction (%)of nitrate-nitrogen loss due to denitrification in the soil <br /> R = Average recharge rate of rainfall -inches per yr(9.0 in.) <br /> Nb= Background nitrate-nitrogen concentration of rainfall recharge, exclusive of wastewater influences <br /> (ppm NO3-N) <br /> Values and Assumptions: <br /> 500 eals/day x 365 days/yr= 146.000 eals/yr= 19,520 cu ft W W/vr = 1.3 in/yr <br /> I= 43,560 cu ft/Ac ft x 5.02 Ac x (1 ft/12 in) <br /> Nw= 112 mg NIL- 10%reduction in each septic tank= 101 mg NIL <br /> d = 10%from biomat formation and 25% from clay soil under filter bed <br /> Nb = Assumed to be 0.1 ppm NOj N <br /> 1.3 in/yr(101 mg N/L) (1 -0.35)+(11 in/w x 0.1 me/L) <br /> Nr = (1.3 in/yr+ 11 in/yr) <br /> Nr = 7.0 ppm as NO3-N or 31.3 ppm as NO3 <br /> LL�_ Page, -6- <br /> Chesney Consulting <br />