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Values and Assumptions: I = 12,000 gals/yr = 1,604.3 cu ft = 0.003 in/yr 145.91 Ac x 43,560 sq ft/Ac x (1 ft/l2 in) Nw = 90 mg N/L d = 31% denitrification factor based on the nitrate -nitrogen concentration reduction observed in the backhoe test pit soil analysis from the initial SSNL Studies. R = 8.82 in/yr Nb = Assumed to be 0.1 ppm NO3-N (0.003 in/�r ((90 mg N/L) 0 - 0.31) + (8.82 x 0.1 mg/LZ Nr = (0.003 in/yr + 8.82 in/yr) Nr = 0.121 ppm as nitrate -nitrogen (NO3-N); 0.537 ppm as nitrate. IV. OWTS OPERATIONAL DESIGN PARAMETERS AND COMPONENTS A. PROPOSED OWTS OPERATION SSS§ 3.7. Influent from the toilet and sink will gravity flow to a 1,200 gallon standard (two piece) septic tank. Effluent from this tank will flow to a Distribution box (D -box) inside the filter bed, as illustrated on the design plans. Equal effluent flow will gravity through two perforated pipes with both ends capped or connected with 90' elbows and a perforated crossover pipe. B. FILTER BED SIZING CALCULATIONS To maintain a small, rectangular footprint for effluent disposal, a filter bed structure is proposed to be installed. The filter bed must be installed under the setback requirements promulgated in Section 1.5 of the OWTS Standards: The vertical ht of the Distillation Area Facility and Control Room building pad area is 3 ft; therefore, the west edge of the filter bed must be a minimum of - 3 ft x 4 = 12 ft from the top edge of the embankment, which will be easily achieved. Due to the fact that the wastewater flow volumes from the Restroom will be extremely small, the filter bed area is based on the parameters also promulgated in the EHD OWTS StandardE: Section 9.7.3 specifies dispersal field application rates for engineer designed systems may be determined by the pert rate. The final pert rate after four hours of testing was 250 min/in. But as noted, in the first one-half hour of testing, the soil accepted 1.56 inches, or 19.2 min/in. The receiving soils readily accept water, but due to its compacted state and high magnesium content, the rate slows precipitously over time. It is my professional engineering judgment that an application rate of 0.1 gals/sf/day is acceptable to be used as an acceptance rate. Therefcre, the calculation for the disposal area becomes: Paiae -6- Chesney Consulting