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t ,C <br /> w <br /> September 4, 2007 <br /> NOA Project Number: E05164A <br /> Page 3 <br /> As a result of mixing in the sink water, the Nc value has decreased from 15.7 mg/L-N in <br /> our previous addendum letter to 15.3 mg/L-N for this analysis. See Table 2 for a summary <br /> of the variables. The calculations are attached to this letter. The Nc value has lowered <br /> slightly but is still exceeding 10 mg/L-N, the maximum drinking water standard for <br /> nitrogen-N. <br /> Based on this analysis, our project recommendations remain unchanged. <br /> Septic System Sizing <br /> The engineered septic system plans dated July 11, 2007 are based on the following design <br /> criteria and incorporate peaking factors. The average daily flow for the nitrate loading <br /> study which is based on long-term averages is was found to be 478 gpd. Using the EHD <br /> septic system sizing criteria which includes peaking factors, the average daily flow is 1,070 <br /> gpd• <br /> Calculation for Filter Bed Disposal Field <br /> (San Joaquin County Onsite Waste Water Disposal Standards, 2003) <br /> Soil Factor(SF). 0.200 -Sand and/or Sandy Loam (EHD Onsite Waste Water Disposal <br /> Standards) <br /> Base Tank Capacity(BTC): 1,200 gallons(EHD Onsite Waste Water Disposal Standards) <br /> A verage Daily Flow(A DF): Office workers 2—35 gpd/person, 200 customers—S <br /> gpd/customer <br /> ADF.• 1,070 gallons per day(number also includes flow peaking factors) <br /> Calculated Tank Capacity(CTC): Value is minimum septic tank volume <br /> Calculation: BTC+ADF= CTC <br /> 1200 gal + 1070 gal= 2,270 gals <br /> Calculation: CTC x SF= LL (feet of equivalent leach line) <br /> 2,270 gals x 0.200 = 454 feet equivalent leach line <br /> 4 disposal trenches 113.5 feet each <br /> It is our opinion that the addition of the 50 g.pdwill not negatively impact the existing <br /> design. We believe that there is a sufficient factor-of-safety to accommodate the relatively <br /> -!mall—increase flow from the kitchen. Therefore, no changes are proposed to the <br /> engineered septic system design with the exception of showing the grease trap and <br /> relocating the water well. The revised plans will be submitted to EHD as a separate <br /> document. <br />