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%.1rr <br /> NLS§ 3.4,3.5, 3.6 PREDICTED NITRATE-NITROGEN LOADING FROM THE PROPOSED <br /> PROJECT USING THE MAXIMUM AVERAGE DAILY FLOW (ADF) BASED ON THE <br /> PARAMETERS DESCRIBED ON PAGES 13 AND 14, AND TAKING THE ENTIRE <br /> PROJECT AREA OF 34.7 ACRES INTO CONSIDERATION: <br /> HANTZSCH IFFINNEMORE EQUATION <br /> INN,0 - 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 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 y✓ u <br /> 12.6 5 q0 <br /> I= 1,586 god+ 150 end x -250 work d/w=434.000 gals=total WW/yr=58,000 cu ft = 0.46 in. <br /> 34.7 Ac x 43,560 sq ft/Ac x(1 ft/12 in.) <br /> Nw = 113 mg N/L: 10%reduction from each of 4 septic tanks(3 Office Building Tank:and One Office Treler Tank)_ <br /> (1-0.6)113 =67.8 mg N/L <br /> d = Assume 25%due to the apparent high denitrification potential occurring between the 5 and 10 ft <br /> depths as observed in the soil chemistry results. <br /> R = 12 in/yr. <br /> Nb= Assumed to be 0.1 ppm NO3-N <br /> 0.46 in/yr(67.8 mg NIL) 0 -0.25)+(12 in/yr x 0.1 mg/L) 2 3 `4 + t <br /> 9 <br /> Nr = (0.46 in/yr+ 12 in/yr) <br /> Nr = 1.9 ppm as nitrate-nitrogen(NO3 N) or 8.8 ppm as nitrate (NO,) <br /> The calculated nitrate loading concentration in the recharge effluent from both the Office Trailers and <br /> New Office Building is calculated to be under the Maximum Contaminant Level limit for nitrate in <br /> drinking water. The variables used in the calculations above are conservative. For example, the use <br /> of 113 mg N/L,which was determined from actual septic tank effluent from a commercial facility, is <br /> a much higher nitrogen concentration than those concentrations published in the sources referenced <br /> in Table 5. Secondly, various researchers place the nitrogen reduction occurring in septic tanks at <br /> 10%to 20%. From the May 8, 2003 Symposium"Onsite Wastewater Treatment- Nitrogen <br /> Removal,"Dr. Stuart Oakley of Chico State University states that"approximately 20% of the total <br /> nitrogen generated is removed in the septic tank."As noted above, a conservative estimate of 10% <br /> was used for each of the four on-site tanks. <br /> 16 <br /> Chesney Consulting <br />