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rFThenitrate <br /> e Loading Mass Balance <br /> oading mass balance calculation is described below for the proposed project. <br /> r estimated nitrate impact to the soil and ultimately to the groundwater is extremely <br /> etermine due to the number of variables involved. The Hantzsche/Finnemore <br /> sed to estimate the resultant average nitrate-nitrogen concentration in the effluent <br /> recharge water at a volume of 540 gpd, and a Total Nitrogen concentration of 112 ppm. This 112 <br /> ppm concentration was determined from septic tank effluent analysis from other similar-type, <br /> commercial projects. <br /> HAN77SCHEIFIAWEMORE EQUATION <br /> o <br /> IN„,fl -d1+RNb <br /> Nr= (I+R) v <br /> Where: A ' <br /> Nr= Resultant average concentration of nitrate-nitrogen in recharge water-(ppm NO3-N) J\ <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 m 112 mg N/L/day) <br /> d = Fraction(%)of nitrate-nitrogen loss due to de ' ficatioin the soil <br /> R = Average recharge rate of rainfall -inches per 30.0 iip.) <br /> Nb= Background nitrate-nitrogen concentration of ra3 all rec arge,exclusive of wastewater influences <br /> (ppm NO,-N) <br /> Values and Assumptions: <br /> 540 gals/day x 365 days/yr= 197,100 gals/yr=26,350 cu R W W/vr = 1.9 in/yr <br /> I= 43,560 cu ft/Ac ft x 3.8 Ac x (1 ft/12 in) <br /> Nw= 112 mg N/L- 10%reduction in each septic tank=3 tanks=30%=78 mg N/L <br /> d = 10% from biomat formation and 25% from clay soil under filter bed <br /> Nb = Assumed to be 0.1 ppm NO3-N <br /> 1.9 in/yr(78 mg N/Ll (1 -0.35)+(9 in/yr x 0.1 mg/L) <br /> �Nr = (1.9 in/yr+9 in/yr) <br /> Nr = ppm as NO3-N 9.6 p s NOy� <br /> The nitrate loading calculated for wastewater effluent recharge from the proposed <br /> iWi below the drinking water Maximum Contaminant Level (MCL) f 10 ppm NO3-N <br /> 45 ppm NO3. a clay soil underlying the filter bed is projected to have at least a ° <br /> nitrification ential. However, by taking advantage of a high clay soil percentage throughout the <br /> soil pe,this denitrification potential maybe even higher, possibly 30%-35%. In addition,the <br /> calculated effluent recharge concentration above does not account for nitrogen uptake by plant root <br /> structures that will absorb effluent at the Infiltrator Chamber louvers and from soil surrounding the <br /> L <br /> bers. The nitrogen uptake concentration is estimated to be between 15% and 25% during <br /> able weather conditions when the interior of the chambers is warm. <br /> Page A 0- <br /> Chesney Consulting <br />