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,00, .� kitchen. This would mainly include cooking, heating and dishwashing. Therefore, it is our opinion that no grease trap will be required for wastewater flows originating from the kitchen. The characteristics of the wastewater flow will be predominately blackwater,with a comparatively small volume of kitchen wastewater, sink water and no graywater from the washing of clothes, bathing, etc. Kitchen wastewater may also consist of the addition of juices or other similar type liquids to the system. There will be no heavy organic loading that would be found with a normally operated kitchen having a garbage grinder or disposal. B. CALCULATED IMPACT FROM NITRATE-NITROGEN LOADING From the anticipated wastewater characteristics described, the nitrogen originating from the project may be at a higher concentration than what would normally be found in a typical domestic or household system. This can be attributed to the lack of a dilution effect which graywater would provide. In contrast to this, it can be theorized the nitrogen concentration may be less because anticipated toilet habits may differ from a residential setting. Because of these discrepancies, a nitrogen concentration based on a "grams/capita/day" cannot be used. The scientific literature cites nitrogen concentrations in septic effluent(residential)typically ranging from 17 mg N/L for basins, sinks, etc. to 140 mg N/L for toilet wastes. Therefore, considering a 70/30 percent usage for toilet water volume and sink water volume, respectively, a value of 103 mg N/L of septic effluent will be used to calculate nitrate-nitrogen loading for this project: 2364 gals/day X 3.79 L/gal =9000 L/day X 103 mg N/L=930 grms N/day X 365 days/yr= 340 kg N/yr X 2.2 lb/kg=750 lbs N/yr- 15 Ac= 50 lbs N/Ac/yr(areal contribution). The following reductions in the nitrate-nitrogen loading from above are anticipated, according to the scientific literature: _ Septic tank(as designed) removes 50%X 750 lbs= 375 lbs Biomat formation removes 10%X 375 lbs=38 lbs Denitrification in silt and clay soil strata removes 25%X 337 lbs= 84 lbs 750 lbs - 500 lbs=250 lbs N/yr total nitrogen load (17 lbs N/Ac/yr areal contribution). To determine nitrogen to the groundwater: Assume 85%reduction in N (from above)= 930 gams N/day - 85%= 139 grins N oxidized to nitrate-nitrogen Dilution water available (avg water use), QAyg=2364 gal/day+avg groundwater flow(QB,) Groundwater flow perpendicular to 350 linear ft of leachfield area= k (hydraulic conductivity of sat. zone)x(i) x 2.5 ft(top mixing layer)X 350 ft= Qs,,.=2 X 10' ft/min(estimated)x(60 x 24) 0.02 x 2.5 ft x 350 ft= 50 ft'/day or 376 gals/day CALCULATED NITROGEN CONCENTRATION TO GROUNDWATER UNDER THE PHASE I AND PHASE H LEACHFIELDS=139 grins/QAvF+Qom, = 139 g/(2364+376) 3.78 x 1000= 13 mg/L NO3-N (nitrate-nitrogen) 5 'valley Ag Rgsearch