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rFC. g MassBalance alance calculation is illustrated below, for the proposed p7Theitrate impact to the soil and ultimately to thegroundwatedifficult to determine due to the number of variables involved. The Hantzsche/Fnnemore Equation is used to estimate the resultant average nitrate-nitrogen concentration in the effluent recharge water at a volume of 150 gpd, and a Total Nitrogen concentration of 112 ppm. This 112 ppm concentration was arrived from septic tank effluent analysis from other similar-type, commercial projects. HANTZSCHEIFINNEMORE EQUATION 2j,(1 -d)+RNb Nr= (I+R) Where: Nr= Resultant average concentration of nitrate-nitrogen in recharge water-(ppm NO3-N) I = Volume rate of wastewater entering the soil averaged over the gross developed area in inches per yr Nw= Total nitrogen concentration of wastewater in N mg/L(112 mg N/L/day) d = Fraction(%)of nitrate-nitrogen loss due to denitrification in the soil R = Average recharge rate of rainfall -inches per yr(9.0 in.) Nb= Background nitrate-nitrogen concentration of rainfall recharge,exclusive of wastewater influences (ppm NO3-N) Values and Assumptions: 150 gals/day x 260 work days/yr=39,000 gals/yr= 5,214 cu ft W W/vr1.4 in/yr 1= 43,560 cu ft/Ac ft x 1.0 Ac x (1 ft/12 in) Nw= 112 mg N/L- 10%reduction in septic tank= 101 mg N/L d = 10% from biomat formation and 25%from clay soil under filter bed(66 mg N/L) Nb = Assumed to be 0.1 ppm NO3 N 1.4 in/yr(101 me N/L) (1 -0.35)+(9 in/yr x 0.1 mu/L) Nr i Nr = 8.9�pm as NO�ing -N or 39�ated 7 ppm as NO3 The nitrate loawastewater effluent recharge from the proposed facility is below the drinking water Maximum Contaminant Level(MCL) of 10 ppm NO3- N or 45 ppm NO3. The clay soil is projected to have at least a 25% denitrification potential. However, by taking advantage of a larger clay soil surface area under the chamber,this denitrification potential may be even higher, possibly 30%-35%. In addition,the calculated effluent recharge concentration above, does not account for nitrogen uptake by grass-type root structures that will absorb effluent at the infiltrator louvers. The nitrogen uptake concentration is estimated to be between 15% and 25% during favorable weather conditions when the int eri� sic warm_ ,This should cause evaporation of the effluent off the soil/effluent inte Qa and onto the louvers for grass root transpiration uptake. Consequently, there is potential for the recharge effluent to be approximately: 15, ad soil denitrification, 15%zone of satlxr tion— 'trification, 20% evapotranspiration uptake= 15% + 15%+ 20%= 50% x 8.9 ppm= .5 ppm NO3-N. Page -8- Chesney Consulting