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7NL3. ,3. PREDICTED NITRATE-NITROGEN LOADING FROM THE PROPOSEDr IC CEMETERY PROJECT USING THE MAXIMUM AVERAGE DAILY FLOW150 GALLONS PER DAY FOR EACH BUILDING(OFFICE AND MAINTENANCE), <br /> AND TAKING THE PROJECT AREA OF 20 ACRES INTO CONSIDERATION: <br /> HANTZSCHEIFINNEMORE EQUATION <br /> INW(I - d) +RNb <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 NIL <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 /> 1= 600 gpd x 365 d/yr=219,000 gals=total WW/yr=29,278 cu ft = 0.40 in. <br /> 20 Ac x 43,560 sq ft/Ac x(1 ft/12 in.) <br /> Nw = 103 mg N/L: 20%reduction from the septic tank =(1-0.2)103 =82 mg NIL <br /> d = Assume 20%due to the fine-grained soil at the potential soil-effluent interface soil chemistry results. <br /> R = 12 in/yr. <br /> Nb= Assumed to be 0.1 ppm NO3-N <br /> 0.40 in/yr(82 mL N/LL1-0 -0.20)+(12 in/yr x 0.1 mg!) <br /> Nr = (0.40 in/yr+ 12 in/yr) <br /> = 2.2 ppm as nitra e-nitrogen(N01!1 `or 9.9 ppm as nitrate(NO3)For Both Disposal Filter Beds <br /> LL// <br /> e calculate ate loading concentration in the recharge effluent from the Office and Maintenance <br /> But Ings 1s calculated to be under the Maximum Contaminant Level limit for nitrate in drinking water. <br /> The variables used in the calculations above are conservative. For example,the use of 103 mg N/L, is a <br /> much higher nitrogen concentration than those concentrations published from household or domestic <br /> sources. Secondly,various researchers place the nitrogen reduction occurring in septic tanks at 10%to <br /> 20%. From the May 8,2003 Symposium"Onsite.Wastewater Treatment-Nitrogen Removal,"Dr. Stuart <br /> Oakley of Chico State University states that"approximately 20%of the total nitrogen generated is removed <br /> in the septic tank." Thirdly,assigning a wastewater flow of 150 gals/day for each toilet,which is based on <br /> older style toilets, incorporates a large safety factor. <br /> 8 <br /> Chesney Consulting <br />