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HANTZSCHE/FINNEMORE EQUATION: <br /> kja(1 -d)+RN <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 N/L <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 /> Values and Assumptions: <br /> I=33 Employees/Customers x 15 gals/person/d x 255 Work d/vr-- 126.225 gals=total WW/yr=16.875 cu ft=0.55 in/yr <br /> 8.42 Ac x 43,560 sq ft/Ac x (I ft/12 in) <br /> Nw= 103 mg N/L: 20%reduction from the septic tank =(1-0.2)103 =82 mg N/L <br /> d = Assume 15%due to fine-grained silty sand soil located at the 8-ft depth with decrease in NO3 N concentration. <br /> R = 11.5 in/yr. <br /> Nb= Assumed to be 0.1 ppm NO3-N <br /> 0.55 in/yr(82 mR N/L) 0 -0.15)+(11.5 in/w x 0.1 mg/L) <br /> Nr = 0.55 in/yr+ 11.5 in/yr) <br /> / 3.3 ppm as nitrate- 'trogen(NO3-N) or 14.8 ppm as nitrate (NO3) <br /> FV ATER MANAGEMENT SYSTEM - OPERATIONAL CRITERIA <br /> SSS§3.7. Dis sslons on the efficient operation of the effluent disposal method, disposal field <br /> longevity, environmental protection are based upon the environmental parameters discussed <br /> within th s report. The wastewater management system to be constructed is described as follows, <br /> and is based upon discussions with EHD personnel and the EHD Sewage Standards. C <br /> A. SEPTIC TANK <br /> Septic tanks store the accumulated sludge, scum and effluent(clear zone)volumes,which in tum <br /> affect treatment of Total Nitrogen(TN)within the tank.. Total Nitrogen is the summation of <br /> ammonia-nitrogen(NH4) and organic nitrogen (proteins,amino acids, enzymes, etc.). Since the <br /> septic tank is predominately anaerobic, nitrogen cannot exist in its oxidized state as nitrate within <br /> the septic effluent for any length of time. Nitrate is quickly reduced to NO or NO2. If nitrate <br /> existed in the tank effluent,this would also be added to ammonium and organic nitrogen to arrive <br /> at Total Nitrogen. <br /> 9 <br />