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TABLE 6 1 <br /> SECOND SEPTIC TANK EFFLUENT SAMPLING EVENT <br /> A&L LABORATORIES TEST RESULTS <br /> SAMPLE ID NPTRATE-NO, TOTAL AMMONIA ORGANIC TOTAL pH <br /> KIELDAHL NITROGEN- NITROGEN ALKALINITY <br /> NITROGEN NH, <br /> (TKN) <br /> Septic Tank BDL 223 mg/L 193 mg/L 30 mg/L 983 mg/L 7.5 <br /> (Below Detectable Limits) <br /> B. CALCULATED NITRATE-NITROGEN LOADING <br /> NLS§3.4,3.5,3.6. The calculated nitrate-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.) Impact from upgradient nitrate agricultural sources, 2.) <br /> Variability in wastewater flows, effluent nitrogen concentrations and dilution effects, 3.) Changes <br /> in groundwater directional flow and elevation, 4.) And the denitrification potential of the <br /> indigenous soils. <br /> HANTZSCHEIFINNEMORE EQUATION <br /> INH,LL-d)+ RNb <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 ac-ft <br /> Nw = Total nitrogen concentration of wastewater in mg N/L <br /> d = Fraction(%)of nitrate-nitrogen combined loss in the soil due to denitrification. <br /> R = Estimated Annual Rainfall Recharge in ac-ft as determined on Page 5. <br /> Nb = Background nitrate-nitrogen concentration of rainfall recharge, exclusive of wastewater influences <br /> (ppm NO3-N)- <br /> Values and Assumptions: <br /> I= 0.71 ac-ft <br /> Nw= 223 mg N/L <br /> d = Assume a conservative 35%based on the nitrate-nitrogen concentration reduction observed in the backhoe test <br /> pit of 23 ppm at the 8 ft depth reduced to 3 ppm at the 12 ft depth,an 87%decrease. <br /> R = 63.44 ac-ft <br /> i <br /> Page -8- <br /> Chesney Consulting <br />