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F <br /> February 22, 2006 <br /> NOA Project Number: E06010A <br /> i <br /> s concentration of 60 mg/L-N will be utilized for both the residential and commercial uses for the <br /> purposes of this calculation. <br /> FJ 3.4.2 Denitrification Estimate <br /> f <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 /> 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 /> ` A standard denitrification factor of 25 percent w s selected for the Site. <br /> //3.5 Nitrate Loading Scenario <br /> Ik ' A nitrate loading scenario was performed to determine the impact from the proposed project. The <br /> scenario utilizes the variables discussed previously which represent the estimated conditions and <br /> uses associated with this project. The following table presents a summary of the nitrate loading <br /> calculation (Plate 11). <br /> l <br /> Summary of Nitrate Mass Balance Analysis. <br /> F Result Acres Average Daily Effluent Concen- Leachfiel_d Deep Percolation of <br /> (Ne) * (A) Flow(Q) (Table 1) tration(Nw) Denitrid' Rainfall(R) <br /> (mg/L-N) �sry �(gpd)_ (mg/L-N) cation(d) E!±te to) (in.) <br /> 3.1 39.09 784 60 25% 5.31 1 <br /> * Maximum contaminant level ka�r£or nitrate in dring-w e -r is 10 mg/L---N. <br /> . <br /> A6 3.6 Impact of Nitrate Loading to Nearby Water Sources <br /> FiThe result of the nitrate loading balance indicates that the proposed use should not cause a buildup <br /> of nitrate in the ground water above 10 mg/L-N over the long term. According to the Hantzsche <br /> ennemore eq 'on and approach, there is a potential for a buildup of nitrates in the ground <br /> water to 3.1 mg/L-N. <br /> 4.0 DISCUSSION OF NITRATE LOADING RESULTS <br /> 1//4.1 Total Nitrate Impact <br /> i Accordingto the Hantzsche and Fennem <br /> ore equation and approach there is a potential for a <br /> buildup of nitrates in the ground water to 3.1 mg/L-N over the long term; this concentration is <br /> ! below the safe drinking water standard. <br /> f <br /> F! <br /> 6 <br />