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Therefore, considering a 20180 percent usage forytoilet water volume and wash water volume,. <br /> respectively, a value of 42 mg NIL(20% of 140 mg NIL plus 80%of 17 mg NIL) of septic effluent <br /> will be used to calculate nitrate-nitrogen loading for this project. A value of 66 mg NIL is typically <br /> used for residential calculations, as indicated in the scientific literature. <br /> // B. CALCULATED NITRATE-NITROGEN LOADING <br /> NLS§3.4,3.5,3.6. The calculated nitraie-nitrogen impact to the soil and ultimately to the <br /> groundwater is difficult to determine due to the large number of variables involved and variables <br /> unknown at this time. These include: 1.)Future installation methods and design of the on-site <br /> wastewater treatment system, 2.) Impact from upgradient nitrate sources,3.)Variability in <br /> wastewater flows,nitrogen concentrations-and dilution effects from effluent and stormwater <br /> recharge, 4.) Changes in groundwater directional flow and elevation, 5.)Denitrification potential <br /> within the soil environment and within the confined and/or un confined:aquifers and 6.) Potential <br /> landscape uptake of nitrogen. <br /> Various scientific methods exist to estimate nitrate=nitrogen loading. This Study uses the <br /> Hantzsche/Finnemore Formula to predict the average resultant concentration of nitrate-nitrogen in <br /> effluent recharge water from a conventional septic system. As calculated below, the property has.been <br /> assessed on a total areal loading basis correlated with-the total number of people on-site every week <br /> of the year since the number of on-site people changes every.Friday., These two factors primarily <br /> estimate the average resultant concentration of nitrate-nitrogen in the recharge water. This <br /> concentration cannot exceed 10 ppm nitrate-nitrogen(45 ppm as nitrate). <br /> PREDICTED NITRATE-NITROGEN LOADING FROM-A COMPLETELY BUILT- <br /> OUT PROJECT USING AN E.H.D. APPROVED:.SEPTIC SYSTEM: <br /> HANTZSCHEIFINNEMORE EQUATION <br /> INS,(1 - d) +R N6 <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 inches per yr <br /> Nw = Total nitrogen concentration of wastewater in mg NIL <br /> d = Fraction(%) of nitrate-nitrogen loss due to denitrification in the soil <br /> R = Average recharge rate of rainfall-inches per yr NLS§3.2 <br /> Nb = Background nitrate-nitrogen concentration of rainfall recharge, exclusive'of wastewater influences <br /> (ppm NO3-N). <br /> Chesney Consulting <br />