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Id <br /> F <br /> ter loading rate: It is assumed there will be approximately 20 residential units on the <br /> property. <br /> med nitrogen concentration in the applied effluent=65 mg N/L <br /> The Hantzsche/Finnemore Equation is used below to estimate the resultant average nitrate-nitrogen <br /> concentration in the effluent recharge water: <br /> HANTZSCHE/FINNEMORE EQUATION <br /> INS,0 - 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 gross developed area in <br /> inches per yr. Total area of subject property =11.32 ac. <br /> Nw= Total Nitrogen concentration of wastewater in mg/L (Typically 65 mg N/L for residential) <br /> d = Fraction(%) of nitrate-nitrogen loss due to denitrification in the soil (15%) <br /> R = Average recharge rate of rainfall - inches per yr(11 in.) <br /> Nb= Background nitrate-nitrogen concentration of rainfall recharge, exclusive of wastewater <br /> influences (ppm NO3-N) <br /> Values and Assumptions: <br /> 250 gals/day x -20 homes x 365 days/yr= 1.825.000 gals/yr= 244.000 cu ft W W// r= 5.9 in/yr <br /> I = 43,560 cu ft/Ac ft x 11.32 Ac x (I ft/12 in) <br /> Nw=65 mg N/L <br /> d = 10% from biomat formation and 15%(=25%) from clay content in soil <br /> Nb = Assumed to be 0.1 ppm NO3 N <br /> 5.9 in/yr(65 mu N_2) (1 - 0.25) + (l I in/yr x 0.1 me/L) <br /> Nr = (5.9 in/yr+ I 1 in/yr) <br /> Nr = 17.0 ppm as NO3-N or 75.6 ppm as NO3 <br /> Therefore, because of proposed wastewater treatment for the development of this property, effluent <br /> from the project with an approximate concentration of 17 ppm NO3-N will not enter the underlying <br /> groundwater. This concentration is almost twice the Maximum Contaminant Level (MCL). <br /> 10 <br /> Ches»ey Consulting <br />