Laserfiche WebLink
r7 <br /> And 4.) Of significant importance is not only the denitrification potential of the indigenous clays, but <br /> equally important is the diminished nitrification potential within the clay soil environment along with <br /> the lack of sufficient alkalinity. The extremely small pore space within the high clay content soil <br /> significantly reduces oxygen content,thus impeding nitrification. <br /> Although there are a number of formulas and equations to predict the inexact science of nitrate impact <br /> potential from septic systems,the Hantzsche/Finnemore Equation is used below to calculate the average <br /> concentration of nitrate-nitrogen in effluent recharge water from the proposed septic system. The <br /> calculations are based on the total areal loading basis of the entire 42-acre APN parcel, correlated with the <br /> annually projected wastewater flows of 156,000 gallons/yr: (600 gpd x 5 dpw=3,000 gpw x 52 wpy= <br /> 156,000 gpy). These two factors primarily estimate the average resultant concentration of nitrate-nitrogen <br /> in the recharge effluent. This concentration shall not exceed 10 ppm nitrate-nitrogen(45 ppm as nitrate). <br /> HANTZSCHEIFIAMMORE EQUATION <br /> IN,y(1 - d) +R Nb <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 combined loss in the high clay content soil due to: <br /> 1.) Prevention of nitrification and 2.)The denitrification of nitrate molecules that may form. <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= 156,000 gals=total WW/Yr=20,856 cu ft =0.13685 in/yr <br /> 42 Ac x 43,560 sq ft/Ac x(1 ft/12 in) <br /> Nw= 146 mg N/L <br /> d = At least 30%as referenced above,due to the high percentage of clay soil(33%)that not only mitigates <br /> nitrification,but also promotes denitrification of nitrate molecules that may form. <br /> R = 9.5 in/yr. <br /> Nb= Assumed to be 0.1 ppm NO3-N <br /> 0.13 685 in/yr(146 mg N/L) (1 -0.30)+(9.5 in/yr x 0.1 mgt) <br /> Nr = (0.13685 in/yr+9.5 in/yr) <br /> LNr5 ppm as nitrate-nitrogen(NO3 N), or 6.9 ppm as nitrate. <br /> Page -8- <br /> Chesney Consulting <br />