Laserfiche WebLink
Nitrate Loading Study <br />Nielsen Property Ripon, California <br />January 15, 2019 Terracon Project No. NA187066 <br />lrerracon <br />Table 3. <br />Potential Quantity of Effluent. <br />Category <br />Number <br />of <br />Bedrooms <br />Potential <br />Number <br />of People <br />per <br />Bedroom <br />Average <br />Effluent <br />Quantity per <br />Person <br />(gpd*) <br />Average <br />days of <br />use per <br />year <br />Potential Average Daily <br />Flow <br />(gpd*) <br />Proposed <br />Residence 4 2 70 365 <br />(4 bedrooms x 2 people per <br />bedroom x 70 gal. per day x <br />365 days per year) / 365 <br />days per year = 560 gpd <br />Potential Average Daily Flow 560 gallons per day <br />*gpd - gallons per day <br />Based on a review of Table 3, the estimated potential sewage flow rate for the proposed future <br />residence is 560-gallons per day. <br />The average total nitrogen concentration of domestic wastewater is normally considered to be 20 <br />to 85 mg/L-N with 35 to 45 mg/L-N being typical (Crites and Tchobanoglous, 1998). It is estimated <br />that commercial use will have higher concentrations of total nitrogen when compared to residential <br />use. For the purposes of the nitrate loading estimate, it is estimated that the average <br />concentration for total nitrogen in wastewater for the project is approximately 35 mg/L-N over the <br />long term. <br />3.5.1 Denitrification Estimate <br />Denitrification is an important process which occurs within the leach field whereby certain bacteria <br />utilize the oxygen in the nitrate (NO3) and release nitrogen gas (N2) to the atmosphere. <br />Denitrification is expressed as a percentage, and the normally accepted range is 10 percent to 35 <br />percent. Soils with higher clay content, moist soil conditions, high pH, and organic material <br />denitrify by about 35 percent, and soils with high sand content and fast percolation rates are <br />estimated to denitrify at a lower rate, about 10 to 15 percent. Based on the sandy soils and <br />relatively low clay content anticipated on the site (Section 1.1), a denitrification factor of 10 percent <br />was selected. <br />3.5.2 Nitrate Loading Scenario <br />The following table presents a summary of the nitrate loading calculation for the proposed site <br />use. A copy of the nitrate loading calculation is included in Appendix B. <br />Responsive • Resourceful • Reliable 7