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16 Febuary 2022 <br />Project No. 22-6747 <br />Page 12 of 13 <br />AdvaneedGe <br />An Employee -Owned Company <br />would not likely degrade the local groundwater. A total of 16.28 ppm of additional nitrogen <br />is estimated to be added to the site over the long term through wastewater recharge from <br />the proposed septic system. The nitrogen loading value is above the desired value of <br />10 ppm. <br />10.0. TOTAL NITRATE IMPACT FROM PROPOSED PROJECT <br />Based on the method and assumptions described, proposed NO3_N mass of wastewater <br />and the calculations of the NO3_N loading predicted, the proposed development may <br />negatively impact NO3_N loading rates within the aquifer. The soils at the site appear to <br />be adequate for nitrate degradation and proper leaching of wastewater. A total of <br />16.28 ppm of additional nitrogen is estimated to be added to the site over the long term <br />through wastewater recharge from the proposed septic system. <br />11.0. MITIGATION METHODS PROPOSED <br />To mitigate any known or potential future impacts of nitrate to soil and groundwater from <br />the proposed septic system, the following mitigations could be implemented: <br />• Maximize wastewater hold time where practical (retention) by installing a larger <br />septic tank (2,000 gallons), or if necessary, install a septic system designed by a <br />professional engineer. <br />• Avoid use of bioattenuation chemicals (bleach etc.). <br />• Properly and regularly maintain the property septic system. <br />• Use EHD criteria for sizing the septic disposal field. <br />If re -location or expansion of leach fields becomes necessary, leach lines should include <br />high organic substrates under and surrounding the lines installed. <br />12.0. CONCLUSIONS AND RECOMMENDATIONS <br />Based on this Soil Suitability and Nitrate Loading Study, AGI concludes and recommends <br />the following: <br />• The percolation rate meets the minimum EHD standards in the proposed septic <br />system disposal field. <br />• The nitrogen loading rate is above the desired value of 10 ppm. <br />0 All approved septic system use should follow the EHD Onsite Wastewater <br />