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26440,8875,&8925 Thornton Road Project No.2017-00010 Page 17 <br /> Table 2. <br /> Typical Quantity of Effluent <br /> Total Average Quantity Days of Use Average Daily Flow <br /> Category Vehicles per per Vehicle (gal) per Year Per Facility <br /> Day <br /> Shell Service Station (400 vehicles x 8 gal x 365 days) / 365 <br /> Vehicles 400 8 365 days=3,200 gal <br /> CPN Service Station (150 vehicles x 8 gal x 365 days) /365 <br /> Vehicles 150 8 365 <br /> days =1,200 gal <br /> Total Average Quantity <br /> Category Employees per Employees Days of Use Average Daily Flow <br /> per Year Per Facility <br /> per Day (gal) <br /> Shell Service <br /> Station/Mini- �1 9 365 (21 people x 9 gal x 365 days) /365 <br /> mart/Restaurant days = 189 gal <br /> Employees <br /> Category Total People Average Quantity Days of Use Average Daily Flow <br /> per Day per Person(gal) per Year Per Facility <br /> Past Food Customers 500 3 365 (400 people x 3 gal x 365 days) /365 <br /> days =1,500 gal <br /> SERVICE STATION VEHICLES(SHELL&CFN) 4,400 gallons <br /> SERVICE STATION EMPLOYEES 189 gallons <br /> FAST FOOD 1,500 gallons <br /> TOTAL AVERAGE GALLONS PER DAY 6,089 gallons <br /> Flow Rate Source:U.S. Environmental Protection Agency. 2002. Design Manua(:Onsite Wastewater Treatment Systems Manua(. <br /> For the site, the total daily toilet use contributing wastewater quantity is 6,089 gallons per <br /> day. The average total nitrogen concentration of domestic waste water is normally <br /> considered to be 20-85 mg/L-N with 35 to 45 mg/L-N being typical (Crites and <br /> Tchobanoglous, 1998). It is estimated that commercial wastewater concentration will be <br /> approximately 85 mg/L-N. <br /> 4.4.2 Denitrification Estimate <br /> Denitrification is an important process which occurs within the leach field whereby certain <br /> bacteria utilize the oxygen in the nitrate (NO3) and release nitrogen gas (N2) to the <br /> atmosphere. Denitrification is expressed as a percentage, and the normally accepted range <br /> is 10 percent to 35 percent. Soils with higher clay content, moist soil conditions, high pH, <br /> and organic material denitrify by about 35 percent,and soils with high sand content and fast <br /> percolation rates are estimated to denitrify at a lower rate, about 10 percent to 15 percent. <br /> A typical denitrification estimate of 35 percent was chosen based on the sandy to silty clay <br /> loam reported for the site. <br /> Petralogix Engineering,Inc. <br /> 26675 Bruella Road,Galt,Ca 95632 <br /> (209)-400-5729 <br /> www.petralogix.com <br />