Laserfiche WebLink
i <br /> 4. NITRATE-NITROGEN LOADING CALCULATIONS <br /> 4_I Nitrate Loading Mass SaIance <br /> The nitrate-nitrogen concentration analyzed from the Flag Ciy�in uen 's sli htly-I gher an the <br /> fconcentration used in the original 2006 report for this projec ($7 mg N/ s. 89.4 mg N <br /> Three different equations and formulas were used in the original loading calculations for this <br /> commercial development. For this study, focus will be>on the Hantzsche/Finnemore Equation since`- <br /> the Total Nitrogen concentration is now reliably estimated, and the equation is widely regarded as <br /> the scientific basis for nitrate-nitrogen loading calculations. <br /> The primary variables involved in the assessment or in quantifying nitrate impact to the underlying <br /> groundwater table under the subject property is the Total Nitrogen concentration, volume of yearly <br /> wastewater.flows, extent of denitrification, land area, and rainfall. <br /> Denitrification.capabilities of the indigenous fine-grained subsurface soils will promote the <br /> denitrification potential in the dispersal areas. Nitrogen consumption in septic tanks and nitrogen <br /> uptake by plants was not incorporated into the following equation. However, it would ultimately <br /> be a significant part of wastewater mariagenlent and is discussed in the Conclusions Section of this <br /> report. <br /> 4.2 Hantzsche/Finnemore`Equation(Based on Complete Build-Ont of the KSC Travel Center) <br /> Li,,Ll -d)+RNN <br /> _ I <br /> I� Where: ` _ / <br /> Nr= Resultant average concentration of nitrate-nitrogen in recharge water-ppm NO,-N. �0 <br /> I .= Volume rate of wastewater entering the soil averaged gross developed area in ^P . <br /> inches per yr. Total wastewater volume used will b 18,0 d as determined on Page 10. <br /> Nw= Total nitrogen concentration of wastewater at 89.4 mg ed on Flag City analytical test results. <br /> Does-hot account for loss-of nitrogen.in septic tanks(_15%+) i <br /> d ' = Fraction(%)of.niti-atc-nitrogen loss due to denitrification in the oil, assumed to be 20%. <br /> R = Average recharge rate of rainfall: 12 inches per yr. Does not acco t for Eva otrans iration. <br /> Ne= Background nitrate-nitrogen concentration of rainfall recharge,ex usive of wastewater <br />',. <br /> influences(ppm NO-=N). <br /> Values and Assumptions ; <br /> 1= 18,000 d x365 d/ 6.570.000. Total WW/yr 878,278 cu ft/ =21.23 in/ 3° 6 o <br /> I 0 c x , s x,(1 ft/12 in) <br /> Nw89:4 g N/L �v? �L- a. <br /> d = ss 0°/ due to a fine-grained silt at the anticipated soil/effluent interface and clay soil at the 8 ft depth. <br /> Nb_ Assuftied to beppm <br /> NO3-N <br /> - Page -13- <br /> Chesney Consulting <br />