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Values and Assumptions: <br /> I= 76,440 gals=total WW/yr= 10,219 cu ft =0.129 in/yr <br /> 21.83 Ac x 43,560 sq ft/Ac x(1 ft/12 in) <br /> Nw= 90 mg N/L <br /> d = Assume 45%due to the percentage of clay soil at the soil-effluent interface. <br /> R = 2.21 in/yr. <br /> Nb= Assumed to be 0.1 ppm NO3 N <br /> 0.129 in/yr(90 mg N/Q (1 -0.45)+(2.21 in/yr x 0.1 m 1Q <br /> Nr = (0.129 in/yr+2.2 1,in/yr) <br /> Nr =2.8 ppm as nitrate-nitrogen(NO3-N), 12.6 ppm as nitrate. <br /> Regarding nitrate loading calculations for the onsite modular home,the EHD has specified wastewater flow <br /> projections from single family residential(SFR)structures to be calculated as follows: 100 gpd for the first <br /> bedroom and 50 gpd for all subsequent bedrooms within the structure. <br /> I= 3 Bedrooms=200 gals/d x 365 =73,000 gals/yr=9,760 cu ft =0.123 in/yr <br /> 21.83 Ac x 43,560 sq ft/Ac x (I ft/12 in) <br /> Nw=45 mg N/L <br /> d = 45%denitrification factor based on the nitrate-nitrogen concentrations observed in the soil chemistry <br /> test results. <br /> R = 2.21 in/yr <br /> Nb= Assumed to be 0.1 ppm NO3 N <br /> (0.123 in/3r)(45 ma N/L)(1 -0.45)+(2.21 x 0.1 mg.1 <br /> Nr = (0.123 in/yr+2.21 in/yr) <br /> Nr = 1.4 ppm as nitrate-nitrogen(NO3 N); 6.2 ppm as nitrate(NO3). <br /> Therefore,the total nitrate contribution by the entire subject Parcel will be 2.8+ 1.4=4.2 ppm nitrate-nitrogen. <br /> IV. O.W.T.S;SYSTEM DESIGN: OPERATIONAL PARAMETERS AND COMPONENTS <br /> A. SEPTIC TANK <br /> Septic tanks store accumulated sludge, scum and effluent(clear zone)volumes,which in turn affect <br /> treatment of nitrogen within the tanks. Detention time calculations demonstrate that when the ADF is <br /> applied to the 2,000 gallon tank,there remains ample detention time. A 2,000 gallon tank is proposed <br /> instead of a 1,200 gallon tank in the event that Phase II is implemented,and to mitigate nitrate loading <br /> potential. <br /> I <br /> -7- <br /> Chesney Consulting <br />