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i 0 January 3, 2006 NOA Project Number: E05164A Table 1. Typical Quantity of Effluent Fj Category Total People per Average Quantity per Average Daily Flow Day Person Per Parcel 2.0 gal/day/customer (200 customers*2.0 gpd) + Commercial 202 . � 14 al/da /em to ee 2 employees* 14 d =428 gpd Note —gpd is gallons per day. E For the subject property, the total daily waste water quantity is428 lions per day. F The average total nitrogen concentration of domestic waste water is normally considered to be 20-85 mg/L-N with 35 to 45 mg/L-N being typical (Crites and Tchobanoglous, 1998). It is estimated that commercial use will have higher concentrations of total nitrogen when compaired to residential use. It is estimated that the average concentration for total nitrogen in waste water for the project is approximately 60 mg/L-N over the long term. � 1 x3.4.2 Denitrification Estimate i Denitrification is an important process which occurs within the leachfield whereby certain bacteria utilize the oxygen in the nitrate (NO3) and release nitrogen gas (N� to the atmosphere. Denitrification is expressed as a percentage, and the normally accepted range is 10 percent to 35 percent. Soils with higher clay content, moist soil conditions,high pH, and organic material denitrify by about 35 percent, and soils with high sand content and fast percolation rates are estimated to denitrify at a lower rate, about 10 percent to 15 percent. A typical denitrification factor of 15 percent was selected for the Site due to the presence of silty sands. 3.5 Nitrate Loading Scenario A nitrate loading scenario was performed to determine the impact from the proposed project. The scenario utilizes the variables discussed previously which represent the estimated conditions and uses associated with this project. The following table presents a summary of the nitrate loading F1 calculation (Plate 9). F4 � - 5 F1