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New Moose Lodge SS/NLS Addendum Page 3 of 4 Our Project Number: E07175A November 26, 2007 from the commercial kitchen will have an approximate concentration of 5 mg/L-N. A weighted average calculation is presented next: Weighted Average Calculation 468 gpd x 85 mg/L-N = 39,780 gpd•mg/L-N 125 gpd x 5 mg/L-N r 625 gpd•mg/L-N 468 gpd + 125 gpd = 593 gpd i 39,780 gpd•mg/L-N + 625 gpd•mg/L-N = ,405 gpd-mg/L-N 40,405 gpd•mg/L-N / 593 gpd = 68.1 mg/L-N It is estimated that the average concentration for total nitrogen in waste water for the project is approximately 68.1 mg/L-N over the long term. 3.4.2 Denitrification Estimate Denitrification is an important process which occurs within the leach field whereby certain bacteria utilize the oxygen in the nitrate (NO3) and release nitrogen gas (N2) 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 denitrification factor of 20 percent was selected for the Site because of the fine grained nature of the soils. 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 calculation for the site. Table 2. S mmary of Nitrate Mass Balance E uation. Result Average Effluent Leachfield Deep Parcel (Nc)* Acres(A) Daily Flow Concentration Denitrification Percolation (mg/L-N) (Q) (gpd) (Nw) (d) of Rainfall (mg/L-N) (R)(in) 1 4.2 22.02 593 68.1 20% 5.76 * Maximum contaminant level (MCL)for nitrate in drinking wa r is 10 mg/L-N. 3.6 Impact of Nitrate Loading to Nearby Water Sources Since the Site is relatively flat, we do not foresee percolating effluent affecting any surface water resources. '--44 902 Industrial Way•Lodi,CA 95240.209.367.3701 •Fax 209.369.4228 ©2007 Nei!O.Anderson&Associates,Inc.