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Spanos Property Page 3 our Project Number: LG5090501 April 14, 2009 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 compared x to residential use. It is estimated that the average concentration for total nitrogen in waste water for the hotel aspect of the project is near residential use, approximately 45 mg/L-N over the long term. The service station and commercial/retail aspect of the project 1s approximately 85 mg/L-N over the long term, and the short order restaurant will have a concentration near approximately 60 mg/L-N. The adjusted nitrogen long term average using a weighted average is 58 mg/L-N. Below Is the long term weighted average of nitrogen in the proposed development waste water. Weighted Ayeraae ofi TotAl Nitro_ etenn Hotel: 2,1.00 gpd x 45 Mg/L-N = 94,500 Restaurant: 1.,050 gpd x 60 mg/1--N = 63,000 Commercial/retail: 900 gpd x 85 mg/L-N = 76,500 234,000 / 4,050 gpd = 58 mg/L-N Denitrification.Estirnalte 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 (N7-) 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 35 percent was selected for the Site because of the fine grained nature of the soils. 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 tabled presents a summary of the nitrate loading calculation for the site (also, see Plate 2). Table 2,. S mmary of Nitrate Mass Balance E uatiarn Result Average Effluent Leachfield Deep Parcel (Nc)* Acres(A) Daily Flow Concentration Denitrification Percolation (Nw) of Rainfall (m9/L-N) (Q)(gpd) (m01LN) (d) (R)(in) 1 14.1 17.1 4,050 58 35% 5.75 *Maximum contaminant level(MCL)far nitrate In drinking water is 10 mg/L-N. 902 Industrial Way•Lodi,CA 95240.7-09.3673701 -Fax 209.369.4-228 92007Ncol0.Anderson&Aosoatare,s,Inc