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Soil Suitability I Nitrate Leading Study 1rerracon <br /> Whitlow Property m Stockton, CA <br /> November 20, 2019 . Terracon Project No. NAt 97078 <br /> Table 10. <br /> Typical quantity of Effluent from Sources. <br /> Average <br /> Total Number effluent Average <br /> Category people of quantity i days of use Average daily flow <br /> per day bedrooms per person per year (gp-d') <br /> (gpd') <br /> �d bedrooms x 2 people per bedroom x 70 <br /> Proposed z 4 70 365 gal. per day x 365 days per year)/365 <br /> Residence <br /> days per year=560 gpd <br /> Total 560 gpd <br /> 'gpd - gallons per day <br /> Based on a review of Table 10, the average daily flow for the proposed residence is 560 gallons <br /> per day. <br /> The average total nitrogen concentration of domestic wastewater is normally considered to be 20 <br /> to 85 mgfL-N with 35 to 45 mgfL-N being typical (Crites and Tchobanoglous, 1998). It is estimated <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 mgfL-N. <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 felease nitrogen gas (Nz) to the atmosphere. <br /> Denitiification 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. Based on the soils <br /> encountered during our borings and presence of clays in the soil column,a denitrification estimate <br /> of 35 percent 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 associates} 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 /> Responsive r Resourceful ■ Reliable 17 <br />