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- 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 /> 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 approximately 808 gpd. <br /> Table 2. <br /> Weighted Average Conversion for Effluent Flow <br /> —' Category Month Gallons per day <br /> Five Day Work Week November- 8 months_x 758-gpd,= <br /> _ <br /> (5/7 of 1,061 gpd=758 gpd) (g months} a 6,064 gpd <br /> Six Day Work Week JuIy-October 4 months x 909 gpd= <br /> (6/7 of 1,061 gpd= 909 gpd) (4 months) ✓ 3,636 gpda"s <br /> Total Average Flow 6,064 gpd+ 3,636 gpd=9,700 months = <br /> / i Sob d <br /> 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 /> k <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 /> G percent. Soils with higher clay content,moist soil conditions,high pH, and organic material <br /> 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 /> i <br /> A denitrification factor of 15 percent was selected for the Site because of the fine grained nature of <br /> the soils. <br /> P <br /> F 6 <br />