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rr�7D. CALC�ULATTEhIMPACT FROM-NITRATE-NITROGEN LOADING <br /> § .4,3.5;3.6 . The calculated or estimated nitrate'lmpact to the soil and ultimately to the <br /> groundwater is extremely difficult to determine due to the number of variables involved. For <br /> example, the number of people to inhabit any future houses is unknown and variable. A value of four <br /> people per household has been used,which incorporates a safety factor. <br /> _ The nitrate-nitrogen loading will be calculated below as described by the Hantzsche and Finnemore <br /> equations.:-.The gross developed area is considered as specified in Hantzsche and Finnemore's <br /> scientific article in the publication Ground Water(1992). <br /> HANTZSCHE IFINNEMORE EQUATION CONSIDERING THE EQUATION IN <br /> TERMS OF "GROSS DEVELOPED AREA": <br /> 1&Q -d)+RL& <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 inches per yr <br /> Nw = Total nitrogen concentration,of wastewater in N mg/L (66 mg N/L/day) <br /> d = Fraction (%) of nitrate-nitrogen loss due to denitrification in the soil / <br /> R = <br /> Ave�g�r6eharge rate of rainfall-inches per yr(15.5 in.) NLS§3.2 -v <br /> Nb R e ground trate-nitrogen concentration of rainfall recharge, exclusive of wastewater influences <br /> (PP 03-N). <br /> Values and Assumbtions: <br /> 70-ga1 ouse(Pe7) x 12 houses-(Inclu second unit dwOSSS§ 3,240 gpd x 365 d/yr1, ,600 gals= 7.47 gal per ft'.;� 158,313 c of waste <br /> r <br /> 158,313 cu MT wastewater <br /> I– 66.3 Ac x 43,560 cu ft/Ac ft x.(1 ft/12 in) <br /> I= '_Q.66 i <br /> Nw=.66-rnglL(Pg.7)- 10% uction of N in the septic tank X59 m <br /> d, i,)0%porn biomat an 25%4enitrification from the clay soils— <br /> Ne = Astiimed to be pp <br /> 0.66 in/ 59 mg NIL). (1 -0.35) +(13.5 inlyr x 0.1 mg/L) <br /> Nr = (06 + 13.5 in/yr) <br /> i Nr 1.9 ppm 's NO,- or 8.4 ppm s NO3 <br /> Page -7- <br /> Chesney Consulting <br />