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Using this method, the two-bedroom home is estimated to produce 150 gpd of <br />wastewater. A typical residential concentration of 35 mg/L of nitrate as N was selected <br />for the proposed residence (Crites and Tchobanoglous, 1998). <br />The estimated sewage flow rates for various uses are available from a number of <br />references. To select appropriate use values for the employee and customers of the <br />Site, Live Oak reviewed the San Joaquin County On-Site Wastewater Treatment <br />Systems Standards (2017), Crites and Tchobanoglous (1998), and US EPA (1980). <br />Crites and Tchobanoglous indicate that 13 gallons per day for each employee is typical <br />for an office or industrial worker, and 5 gallons per day per user is typical for a public <br />lavatory; these rates were used for the facility's employees and customers. The nitrate <br />as nitrogen (N) concentration of the employee use is estimated to be 85 mg/L (US EPA, <br />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 184.5 gallons per day <br />(gpd). Through the use of a weighted average, the average concentration of the <br />different effluent flows and concentrations was determined to be 44.3 mg/L-N at 184.5 <br />gallons per day. Please see the following tables: <br />Table 4. Average Daily Flow Calculation <br />Use Units Rate Subtotal Reduction Average Daily <br />Flow <br />Residence 2 bed <br />rooms <br />150 ga1/2BR/day 150 gpd None 150 gpd <br />Employee 1 13 <br />gal/person/day 13 gpd 12/8 19.5 gpd <br />Customers 3 5 gal/person/day 15 gpd None 15 gpd <br />Total 184.5 gpd <br />Reduction factors convert calculated flow into average daily flow over a year. The factor 12/8 refers to hours worked <br />versus a standard workday. No reduction is used for a residence since it is continuously occupied. <br />LOGE 2114 Page 11