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Soil Suitability/Nitrate Loading Study <br /> Proposed Global Carrier Inc. ■ Manteca, California 1rerracon <br /> August 8, 2018 ■ Terracon Project No. NA187034 <br /> Table 7. <br /> Typical Quantity of Effluent. <br /> Total Average Quantity <br /> Category People per Person Average days of Average Daily Flow <br /> per Day (gallons) use per year <br /> Office (3 person x 30 gal x 260 <br /> Permanent 3 *30 260 days)/365 days per year <br /> Employees = 64.1 gpd <br /> Tire& Brake <br /> Shop (4 person x 15 gal x 260 <br /> Permanent 4 *15 260 days)/365 days per year <br /> Employees =42.7 gpd <br /> (10 person x 5 gal x 365 <br /> Visitors 10 *5 365 days)/365 days per year <br /> = 50.0 gpd <br /> Average Daily Flow 156.8 gallons per day <br /> Note:gpd is gallons per day.*Value cited from the San Joaquin County Onsite Wastewater Treatment Standards(2017)Table 6.6. <br /> The average total nitrogen concentration of domestic wastewater is normally considered to be 20- <br /> 85 mg/L-N with 35 to 45 mg/L-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. It is estimated that the average concentration for total nitrogen in wastewater for the project <br /> is approximately 85 mg/L-N over the long term. <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 soil borings, the proposed new leach field is expected to be located <br /> within silty sandy soils in the upper 10 feet. Given the geology and separation from groundwater, <br /> a denitrification estimate of 15 percent is anticipated. <br /> Responsive■ Resourceful ■ Reliable 16 <br />