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4 <br /> ri <br /> F <br /> U4 4 February 28,2007 <br /> NOA Project Number: E07023A <br /> For the subject property, the total daily waste water quantity is 1,061 gallons per day. A five-sevenths <br /> conversion was used to account for a five day work week in the eight months of November through <br /> t as June,and a six-sevenths conversion was used to account for a six day work week in the four months <br /> of July through October. Using a weighted average, a total average daily flow from the trucking <br /> operation will be approximately808 gpd. <br /> F <br /> C-� <br /> Table 2. <br /> Weighted Average Conversion for Effluent Flow <br /> Category Month Gallons per day <br /> November- <br /> Five Day Work Week 8 monthsrx 758•gpd..= <br /> (5/7 of 1,061 gpd= 758 gpd) J' 1e6,064 gpd_.2 <br /> (8 months) <br /> F; <br /> Six Day Work Week July-October 4 months x 909 gpd= <br /> 9 �+ (6/7 of 1,061 gpd= 909 gpd) (4 months) 3;63G <br /> Total Average Flow 6,064 gpd f 3,636 gpd=9,700/ 12 months = <br /> 808 d <br /> t Note —gpd is gallons per day. <br /> The average total nitrogen concentration of domestic waste water is normally considered to be <br /> 20-85 mg/L-N with 35 to 45 mg/L-N being typical (Crites and Tchobanoglous, 1998). It is <br /> estimated that commercial use will have higher concentrations of total nitrogen when compared to <br /> residential use. Because the operation will have a shower facility, the concentration will be diluted <br /> significantly. It is estimated that the average concentration for total nitrogen in waste water for the <br /> project is approximately 60 mg/L-N over the long term. <br /> 3.4.2 Denitrification Estimate <br /> Denitrification is an important process which occurs within the leach field whereby certain bacteria <br /> + utilize the oxygen in the nitrate (NO3) and release nitrogen gas (N, to the atmosphere. <br /> Denitrification is expressed as a percentage, and the normally accepted range is 10 percent to 35 <br /> percent. Soils with higher clay content, moist soil conditions,high pH, and organic material <br /> F ; denitrify by about 35 percent, and soils with high sand content and fast percolation rates are <br /> estimated to denitrify at a lower rate,about 10 percent to 15 percent. <br /> A denitrification factor of 15 percent was selected for the Site because of the fine grained nature of <br /> the soils. <br /> a <br /> 1.1 <br />