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16 Febuary 2022 <br />Project No. 22-6747 <br />Page 10 of 13 <br />AdvancedGeo <br />An Employee -Owned Company <br />The total nitrate -nitrogen (NO3_N) average concentrations in domestic waste ranges <br />between 20 to 85 mg/1-N with an average of 45 mg/1-N when washing and sanitation is <br />considered. <br />The weighted average calculation for total nitrogen concentrations for onsite residential <br />flow is proposed as the following: <br />• Residential volume 200 gpd. <br />• Home use concentration 45 mg/1-N (EHD standard). <br />• The flow concentration of 9,000 mg/1-N gallon. <br />9.5. DENITRIFICATIONS CAUSED BY SOILS <br />The process of denitrification is important when utilizing subsurface septic lines and <br />regularly occurs in the soil within the leach fields where bacteria utilize oxygen in the <br />nitrate to release nitrogen gas out to the atmosphere. The denitrification process is <br />controlled by waste concentrations, soil type, annual rainfall, pH of the soils, total organic <br />concentration of the soil (TOC) and exposure time to nitrogen. The soils with a high or <br />moderate clay content, higher organic content, high pH, and adequate soil moisture <br />denitrify the concentrations by approximately 30 percent and less desirable soils with <br />more sands and faster percolation rates (less moisture and clay content) denitrify only <br />about 10 percent. A denitrification factor of 30 percent was selected for the calculation <br />based on the clay and loam soil existing at the site. <br />9.6. MASS BALANCE OF NITROGEN LOADING <br />The EHD requires the user to consider all potential sources identified for wastewater <br />generation. Further, the EHD supports the use of Hantzsche/Finnemore, or other <br />appropriate formula/model to calculate a mass of nitrogen loading. <br />RESIDENTIAL: <br />The Hantzsche / Finnemore (Nr) equation for residential home application: <br />Nr=IxNw(1-d)+RxNb=(I+R) <br />Definitions. <br />Nr = The average concentration of nitrate -nitrogen in the recharged wastewater parts per <br />million of nitrate -nitrogen. <br />I = Volume rate of wastewater entering the soil averaged over the gross developed area <br />