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FFK= vertical permeability as most conservative= 11.9 cm/hr x 24 hr/day x 0.0328 ft/cm=9.3 ft/day above) h to width ratio= 1, therefore, n= 1.7193 (coarse sand) days (10 yrs) Zm = 0.317x 105.2 x 0.0246 x 3.79 = 3.1 ft It appears that the maximum mound height that may occur under the filter bed, and above the current static water table depth is 3.1 feet. This would leave a marginal distance of approximately five feet between the soil/effluent interface and the top of the mound(soil/effluent interface =2 ft below grade+ 5 ft separation distance=7 ft, which the mound may rise to this depth.) For wastewater treatment to occur, the distance effluent must travel under unsaturated conditions through the soil environment is generally regarded to be five feet. Wastewater treatment in this respect is taken to be destruction of bacteria and viruses. If it is determined at some point in the future that mounding effects are preventing proper effluent treatment and disposal, the area designated as 100%replacement area may have to be activated. This may occur prior to attaining 2,500 gpd effluent flow volumes, but is unlikely. IV. SEPTIC SYSTEM OPERATIONAL CRITERIA AND DESIGN A. Nitrate Loading Mass Balance Wastewater characteristics emanating from the Aqua Pool and Spa facility are anticipated to be dissimilar to typical household domestic wastewater since there will be only toilets and sinks with no showers or washing machines. In determining nitrogen concentrations of septic influent and effluent, per capita intake of nitrogen per day must be estimated. The average American consumes between 70 and 140 g of N/day. Since nitrogen comprises 16% of the weight of the average protein, 16%of 70 g N= 11 g N/capita/day and 16% of 140 g N= 22 g N/capita/day. The average of these two values is 17 g N/capita/day of theoretical influent. The calculated or estimated nitrate impact to the soil and ultimately to the groundwater is extremely difficult to determine due to the number of variables involved. The concentration of nitrogen in septic system effluent is specified as units of mg N/L. Unfortunately, these units superimpose wastewater flow variability onto nitrogen influent variability, thus creating even greater variability. One researcher has averaged the means from 20 other studies to arrive at a concentration of 62 t 21 mg N/L in septic tank effluent. However, from previous studies within the County of San Joaquin, a small number of commercial facilities have averaged a Total Nitrogen concentration of 87 mg N/L. This concentration of 87 mg N/L can be considered a high, or strong strength wastewater, but will be used because of its safety factor in the calculations below. This is the estimated nitrogen loading in the effluent discharged from the facility without treatment of the effluent by the EnviroServer unit. Page -6- Ch&my Consulting