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lierracon Soil Suitability / Nitrate Loading Study <br />Azevedo Property Acampo, CA <br />June 19, 2019 Terracon Project No. NA197009 <br />that commercial use will have higher concentrations of total nitrogen when compared to residential <br />use. For the purposes of the nitrate loading estimate, it is estimated that the average <br />concentration for total nitrogen in wastewater for the residence is 45 mg/L-N and approximately <br />85 mg/L-N for the agricultural building. <br />2.3.4.2 Denitrification Estimate <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 (N2) 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 />Based on the results of the shallow soil borings, the proposed new leach field is expected to be <br />located within sandy clayey soils that cemented with depth. Based on the soils encountered <br />during our borings and anticipated slow percolation rate, a denitrification estimate of 35 percent <br />was selected. <br />2.3.5 Nitrate Loading Scenario <br />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 for the site. A copy of the nitrate loading calculation is included in Appendix F. <br />Table 11. <br />Summary of Nitrate Mass Balance Equation. <br />' <br />Land Use <br />Result <br />(Nc)* <br />(mg/L-N) <br />Acres <br />(A) <br />Average <br />Daily Flow <br />(Q) (gpd) <br />Effluent <br />Concentration <br />(Nw) <br />(mg/L-N) <br />Leachfield <br />Denitrification <br />(d) <br />Deep <br />Percolation <br />of Rainfall <br />(R) (in) <br />Residence 8.1 4.97 560 45 35% 4.49 <br />Agricultural Building 2.9 4.97 60 85 35% 4.49 <br />Nitrate as N Total 11.0 <br />A <br />, <br />* Maximum contaminant level (MCL) for nitrate in drinking water is 10 mg/L-N. <br />Based on the nitrate loading balance, nitrate levels for the existing residence is 8.1 mg/L-N. The <br />proposed development is anticipated add 2.9 mg/L-N for a total of 11 mg/L-N, slightly above the <br />MCL of 10.0 mg/L-N. <br />2.3.6 Impact of Nitrate Loading to Nearby Water Sources <br />Responsive Resourceful Reliable 16