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Ix <br /> J <br /> 1° <br /> F1 January 16, 2007 <br /> NOA Project Number: E07009A <br /> + t + The following table reiterates the septic waste water uses associated with the site. The rates <br /> presented from the references provide general guidance but do not always reflect a match in usage. <br /> Careful examination,professional judgement, and experience are necessary to select a reasonable <br /> flow rate estimate. The flow rates selected for the uses associated with this project are presented <br /> F,i next <br /> Table 1. <br /> Typical Quantity of Effluent <br /> FTotal People Average Quantity per Average Average Total Average <br /> Category Daily Flow Daily Flow on <br /> per Day Person Daily Flow <br /> per Facility Site <br /> Gas Station/ 6 employees 13 gal/day/employee 78 gpd <br /> Convenience 708 gpd <br /> Store 1,125 customers 56 gaI%d mplo}ee_ 630 gpd .._ ..��,. <br /> 872 gpd <br /> Commercial 10 employees 10 gal/day/employee 100 gpd 164 gpd <br /> Building <br /> 32 parking spaces 2 gal/day/customer 64 gpd <br /> Note —gpd is gallons per day. <br /> For the subject property, the total dai&waste water quarrdo:is 872g <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. It is estimated that the average concentration for total nitrogen in waste water for <br /> the project is approximately 85 mg/L-N over the long term. <br /> F3.4.2 Denitrification Estimate <br /> Denitrification is an important process which occurs within the leach Meld whereby certain bacteria <br /> utilize the oxygen in the nitrate (NO,) 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 /> FA denitrification factor of 35 percent was selected for the Site because of the fine grained nature of <br /> the soils. <br /> i <br /> F <br /> F <br /> 6 <br /> G F <br />