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A maximum of five trucks per day enter the Site, Mr. Judge stated, and the business <br />operates five days per week. Mr. Judge indicated that at some point in the future he <br />might build a small office/shop/storage building for the business. He does not anticipate <br />more than 10 trucks per day in the future, though he stated that legally he is allowed up <br />to 25 trucks on-site. To address the worst-case nitrate loading scenario, 25 trucks have <br />been included in the nitrate loading calculation. <br />The estimated sewage flow rates for various commercial uses are available from a <br />number of references. To select appropriate use values for the employees of the Site, <br />Live Oak reviewed the San Joaquin County On -Site Wastewater Treatment Systems <br />Standards (2017), Crites and Tchobanoglous (1998), and US EPA (1980). Crites and <br />Tchobanoglous indicate that 13 gallons per day for each employee is typical for an <br />office or industrial worker, and 5 gallons per day per user is typical for a public lavatory; <br />these rates were used for the facility's employee and visiting truckers. The nitrate as <br />nitrogen (N) concentration of the employee and trucker use is estimated to be 85 mg/L <br />(US EPA, 1980). <br />The estimated flow values discussed here should not be used for the design and sizing <br />of the septic system. The design and sizing of the septic system should utilize the San <br />Joaquin County Environmental Health Department On -Site Wastewater Treatment <br />Systems Standards, which incorporates peak and surge flow factors. The estimates <br />used in the On -Site Wastewater Treatment Systems Standards may be greater than <br />those discussed here. <br />The maximum average daily flow for the Site was estimated to be 117.2 gallons per day <br />(gpd), as presented in the following table: <br />Table 4. Average Daily Flow Calculation <br />Use Units Rate Subtotal Reduction Average Daily Flow <br />Employees 3 13 gal/person/day 39 gpd 5/7 27.9 gpd <br />Visiting Truckers <br />(5 anticipated; 25 gal/person/day 125 gpd 5/7 89.3 gpd <br />max. 25 allowed) <br />Total 117.2 gpd <br />Reduction factors convert calculated flow into average daily flow over a year. The factor 5/7 refers to a standard M -F <br />workweek. <br />LOGE 2236 Page 11 <br />