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L <br /> Y. NITRATE LOADING <br /> Nitrate loading projections and calculations will be based upon the above-referenced erenced average <br /> weekly wastewater flows. Due to the variability in day-to-day wastewater flows from the Mall <br /> and the Bingo Parlor, weekly flows are the smallest unit of time whereby total flows can be <br /> estimated. <br /> As cited in the literature, evaluation of nitrogen discharged from septic systems is usually in <br /> terms of mg N per L. The most commonly accepted figure of nitrogen concentration in <br /> discharged effluent is 62 mg N per L (Bauman, 1985). This figure is equal to 275 mg NO3 per L. <br /> Estimating the total weekly wastewater flow for both the Open Air Mall and the Bingo Parlor at <br /> 74,750 gallons, the total weekly nitrogen loading will be 20 kg N/week or 1,019 kg N/year. This <br /> is a 7%decrease over last year's calculations of 1,092 kg N/year. <br /> A prediction of nitrate impact of sewage disposal from the entire Open Air Mall can be made <br /> from a mass balance, taking into consideration only inputs from wastewater, denitrification <br /> f losses and rainfall. In Dr. John Finnemore's paper (1992), he describes a formula for the average <br /> Lconcentration of NO3-N in effluent recharge water, as reported in mg/L• <br /> n,=InJ I-d) =rnb where: <br /> I +r <br /> I = average volume rate of wastewater entering the soil over the gross area, in inches per year <br /> L (leachfield and pit areas). <br /> r=average rainfall in inches per year. <br /> nu,=total nitrogen concentration of wastewater in mg/L. <br /> ne background NO,3-N concentration of rainfall recharge, independent of wastewater influences. <br /> d=fraction of NO3-N loss due to denitrification in the soil. <br /> 7 <br /> L L <br /> Valfey Ag P4search <br />