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FACRES <br /> ,3.5,3.6. PREDICTED NITRATE-NITROGEN LOADING FROM THE PROPOSED <br /> OF C ST CHURCH USING THE MAXIMUM AVERAGE DAILY FLOW(ADF)BASED <br /> P TERS DESCRIBED,AND TAKING THE ENTIRE PROJECT AREA OF 2.68 <br /> THE EVENTUAL SIZE OF THE CHURCH PROPERTY)INTO CONSIDERATION: <br /> HANTZSCHEIFINNEMORE EQUATION <br /> INa(1 - d) +RNA <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 <br /> d = Fraction(%)of nitrate-nitrogen loss due to de ' cation in a soil <br /> R = Average recharge rate of rainfall -inches per yr S§3.2 <br /> Nb= Background nitrate-nitrogen concentration of rai all rech ge,exclusive of wastewater influences <br /> (ppm NO3-N) <br /> Values and Assumptions <br /> I= 375 gpd x 365 d/vr= 136.875 gals=total W W/vr= 18.299 cu ft = 1.88 in. <br /> 2.68 Ac x 43,560 sq ft/Ac x(1 ft/12 in.) <br /> Nw = 113 mg N/L: 20%N reduction occurring in the septic tank and 10%in biomat=(1-0.3)113 =79 mg N/L <br /> d = Assume 25%due to the clay loam nature of the native soil and therefore medium-high denitrification potential <br /> R = 9.25 in/yr. <br /> Nb= Assumed to be 0.1 ppm NO,--N <br /> 1.88 in/yr(79 mg N/L) (1 - .25)+(9.25 in/yr x 0.1 mg/L) <br /> Nr = (1.88 in/yr+9.25 in/yr) <br /> Nr = 10.0 ppm as nitrate-nitrogen(NO3 N) or 45 ppm as nitrate(NO3) <br /> The calculated nitrate loading concentration in the recharge effluent from the People of Christ Church is <br /> calculated to be right at the Maximum Contaminant Level limit for nitrate in drinking water. The variables <br /> used in the calculations above are conservative. For example,the use of 113 mg N/L,which was determined <br /> from actual septic tank effluent from three Churches in San Joaquin County is a much higher nitrogen <br /> concentration than those concentrations published in the sources referenced in Table 6. Secondly,various <br /> researchers place the nitrogen reduction occurring in septic tanks at 10%to 20%. From the May 8, 2003 <br /> Symposium"Onsite Wastewater Treatment-Nitrogen Removal,"Dr. Stuart Oakley of Chico State <br /> University states that"approximately 20%of the total nitrogen generated is removed in the septic tank."As <br /> noted above,this estimate of 20%was used for nitrogen reduction occurring in the three septic tanks. <br /> 14 <br /> Chesney Consulting <br />