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Wastewater Characteristics <br /> 1 The domestic wastewater generated from the Church and School facilities will be composed of <br /> blackwater from toilets and greywater from hand washing. There will be no high organic loading <br /> from food preparation and no additional greywater flows from gym showers, laundry, etc. <br /> To utilize accurate nitrogen concentrations in the nitrate loading calculations, a septic tank effluent <br /> sample was retrieved from the second compartment of the north 9,600 gallon septic tank. This tank <br /> serves the Church, students, teachers and administrative staff. As noted,the organic N fraction <br /> exceeds the ammonia N fraction by 2.3x. Typically, the organic fraction is approximately 25% of the <br /> TKN. However,the TKN is the main constituent. The following Table summarizes the analysis of <br /> the septic tank effluent, with the Lab results found in Appendix F: <br /> TABLE 5 <br /> SEPTIC TANK EFFLUENT ANALYSIS <br /> SAMPLE ID NITRATE-N TOTAL AMMONIA ORGANIC TOTAL pH <br /> (NO,-N) KJELDAHL NITROGEN- NITROGEN ALKALINITY <br /> NITROGEN NH, (CALC) <br /> (TKN) r <br /> North Septic 0.975 131 mg/L 36 mg/L 95 mg/L 727 mg/L 7.47 <br /> Tank <br /> B. CALCULATED NITRATE-NITROGEN LOADING <br /> NLS§3.4,3.5,3.6. The calculated nitrate-nitrogen impact to the soil and ultimately to the <br /> groundwater is difficult to determine due to the large number of variables involved and variables <br /> unknown at this time. These include: 1.) Nitrate impact from upgradient agricultural sources, 2.) <br /> Variability in wastewater flows, effluent nitrogen concentrations and dilution effects, 3.) Changes in <br /> groundwater directional flow and elevation, 4.) The denitrification potential of the indigenous soils. <br /> HANTZSCHE/FINNEMORE EQUATION <br /> 2jW(1 -d)+RNE <br /> Nr= (I+R) <br /> Where: <br /> Nr = Resultant average concentration of nitrate-nitrogen in recharge water-(ppm NO3-N) <br /> I = Volume rate of wastewater entering the soil averaged over the gross developed area in ac-ft <br /> Nw = Total nitrogen concentration of wastewater in mg N/L <br /> d = Fraction(%)of nitrate-nitrogen combined loss in the soil due to denitrification. <br /> R = Estimated Annual Rainfall Recharge in ac-ft as determined on Page 5. <br /> LNb = _Background nitrate-nitrogen concentration of rainfall recharge, exclusive of wastewater influences <br /> (ppm NO3-N). <br /> Page -7- <br /> Chesney Consulting <br />