Laserfiche WebLink
F <br /> ariability in the numbers of on-site personnel over the course of a year, averages willalculating wastewater flows and nitrate-nitrogen loading. These averages areelow: <br /> EMPLOYEE YEAR-ROUND AVERAGES <br /> Office 21 Employees: 8:00 A.M.to 5:00 P.M. <br /> Monday through Saturday <br /> 7 mechanics on Day Shift <br /> Mechanics 4 Mechanics on Night Shift <br /> Monday through Saturday <br /> Truck Drivers 60 Trucks(30+90=2)with 60 Drivers. 100%using on-site facilities <br /> before and/or after a shift,Monday through Saturday <br /> B. CALCULATED IMPACT FROM NITRATE-NITROGEN LOADING <br /> From the anticipated wastewater characteristics described, the nitrogen emanating from the <br /> project may be at a higher concentration than what would normally be found in a typical <br /> domestic or household system. This can be attributed to the lack of the dilution effect that <br /> graywater from showers, laundry, etc. would provide. The scientific literature cites nitrogen <br /> concentrations in residential septic effluent typically ranging from 17 mg N/L for basins, sinks, <br /> etc. to 140 mg N/L for toilet wastes. Therefore, considering a 70/30 percent usage for toilet <br /> water volume and sink water volume, respectively, a value of 103 mg N/L of septic effluent will <br /> be used to calculate nitrate-nitrogen loading for this project. The loading projection is based on <br /> the maximum number of employees who may potentially use the toilet/sink, etc. on a daily basis, <br /> which incorporates an acceptable safety factor as illustrated below: <br /> 21 + 11 +60 = 92 people. <br /> Each person is assigned 10 gallons per day per San Joaquin County Sewage Standards: <br /> 92 people X 10 gals/person/day=920 gals/day X 3.79 L/gal=3,487 L/day X 103 mg N/L= 359 <br /> grams N/day X 312 days/yr (6 days/wk-52 wks/yr)= 112 kg N/yr X 2.2 lb/kg=246 lbs N/yr <br /> The following reductions in the nitrate-nitrogen loading from above (246 lbs N/yr) are <br /> anticipated, according to the scientific literature: <br /> Septic tank system (as proposed)removes 50%N x 246 lbs = 123 lbs <br /> Biomat formation removes 10%X 123 lbs= 111 lbs <br /> Denitrification in silt/clay soil strata removes 20%X 111 lbs = 89 lbs <br /> 89 lbs N/yr=total nitrogen load. <br /> 5 <br /> valley. igResearck <br />