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i <br /> r7Nw- 87 mg N/L <br /> d = Assume 20%due to a fine-grained silt at the anticipated soiVeffluent interface and clay soil at the 10 ft depth. <br /> R = 12 in/yr. <br /> Nb= Assumed to be 0.1 ppm NO3-N <br /> Y <br /> 30.66 in/yr(87 mg N/L) 0 -0.20)+ (12 in/yr x 0.1 me/L) <br /> i Nr = (30.66 in/yr+ 12 in/yr) <br /> th7r 50T0 ppy arinffa-te=nitrogen(NO3`N)'or 22`1'7appm a's nitrate (NO3)m <br /> Resu nt Re arge(Nr)from both Phase 1 and Phase 2 is 5x the Maximum Contaminant Level(MCL) <br /> for nitrate-nitrogen (10 ppm). iGiven thatrthe.wa--steamer flows or Phase bare approxtm4te[y_one-lia[fj <br /> Lofthetotakivaskiyater fl liime'a illustrated_in Table 8 on Page,1,7, the nitrate[b�din��or,Ph_s 1 <br /> 1Cezclusively'wall be approximately 25 ppmLnitrate=nitrogen (NO3 N);0 2:SxYhe MCL. <br /> Hantzsche /Finnemore Equation For.Gas-Station and-Convenience-Store Exclusively: <br /> INw(1 -d)+R Nb <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 <br /> inches per yr. Total wastewater volume for the Gas Station/Convenience Store will be the lesser <br /> volume calculated in Column 3,Page 17 of 2,250 gpd x 365 days/year= 821,250 gals , 7.48 gals <br /> per ft' = 109,800 cu ft of wastewater. Does not account for Evapotranspiration. <br /> Nw= Total nitrogen concentration of wastewater at 87 mg N/L based on discussion referenced above. <br /> Accounting for loss of nitrogen in septic tanks at 15%= 87 (1- .15) = 73.95 and loss through biomat <br /> = 10%=73.95 -7.4=66.55 mg N/L. <br /> d = Fraction (%) of nitrate-nitrogen loss due to denitrification in the soil <br /> R = Average recharge rate of rainfall: 12 inches per yr <br /> Nb= Background nitrate-nitrogen concentration of rainfall recharge, exclusive of wastewater <br /> influences (ppm NO.-N) <br /> Values and Assumntions <br /> I= 821,250 gals = total WW/yr= 109,800 cu ft/yr=2.75 in/yr <br /> 11.00 Ac x 43,560 sq ft/Ac x (1 ft/12 in) <br /> Nw=66.55 mg N/L <br /> d = Assume 20%due to a fine-grained silt at the anticipated soil/effluent interface and clay soil at the 10 ft depth. <br /> R = 12 in/yr. <br /> Nb= Assumed lobe 0.1 ppm NO3 N <br /> 2.75 in/yr(66.55 mg N/L) 0 -0.20) + (12 in/yr x 0.1 me/L) <br /> Nr = (2.75 in/yr+ 12 in/yr) <br /> Nr 10 02ppm.as:n traten trogi (NO3-N) or 4S:Orppm asrnitrate{NO3)a <br /> Page -20- <br /> Chesney Consulting <br />