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MOUND DESIGN WORKSHEET <br /> (For Flows up to 1200 gpd) <br /> A. FLOW Estimated Sewage Flows in Gallons per day <br /> Estimated OD gpd (see pages D-7 or 1-3, 4, 5) Number ( ) <br /> 6 <br /> or measured gpd x 1.5 = Bedof <br /> Type I Type It Type III Type <br /> IV <br /> 2 300 225 180 <br /> B. SEPTIC TANK LIQUID VOLUMES 3 450 300 218 6• <br /> 4 600 375 256 s t 1°0 <br /> gallons (seepages C-3 or C-5) 5 750 450 294 a <br /> 6 900 525 332 lit. <br /> t. <br /> 7 1050 600 370 coin <br /> C. SOILS (refer to site evaluation) 8 1200 675 408 cd mad <br /> 1. Depth to restricting layer = 13 inches Septic Tank Capacities,in ger 1104131 <br /> Number of :Minimum Liquid Liquid capacity with <br /> 2. Depth of percolation tests = 2 inches bedrooms Capacity garbage disposal <br /> 3. Percolation rate 4ilImpi 2orleu 750 1125 <br /> 3 or 4 1000 1500 <br /> 4. Land slope % 4 or 6 1500 2250 7.s or 9 2000 3000 <br /> over 9 ..-- <br /> D. ROCK LAYER DIMENSIONS <br /> 1. Multiply flow rate by 0.83 to obtain required area of rock <br /> layer: Daily Flow x • 60n = <br /> C gpd x 0.83 sq. ft./gpd = sq. ft. <br /> 2. Select width of rock layer (10 feet or less) = 1 0 ft. <br /> 3. Length of rock layer = Area _ Width = <br /> 500 sq. ft. _ i'v ft. = SO ft. Rock Bed <br /> .r.:.j.f.j...,.f...f.,.f.r.. .T <br /> • l•!•t•l•:•t•l•t•t•l•r•r•tV <br /> :•ti•ti••.•ti•• ti••.•ti,:•e: ti .reel:•�SlVidth S70 ft. <br /> 0•tl-:!r•l!:•:Wit_::1::�:�::l4r <br /> E. ROCK VOLUME i Length <br /> 1. Multiply rock area by rock depth to get cubic feet of rock; <br /> 9 sq. ft. x 1 ft. _ cu. ft. <br /> 2. Divide cu. ft. by 27 cu. ft./cu. yd.to get cubic yards; <br /> cu. ft. -1. 27= N cu. yd. <br /> 3. Multiply cubic yards by 1.4 to get weight of rock in tons; <br /> ICI cu. yd. x 1.4 ton/cu. yd. = 21 tons. <br /> 1 <br /> F. ADSORPTION WIDTH . <br /> 1. Percolation rate in top 12 inches of soil is `T1 mpi Absorption Width Sizing Table <br /> Percolation Rate Gallons Ratio of <br /> 2. Select allowable soil loading rate from table on page E-; in Minutes Soil Texture per day per Absorption width <br /> Inch(MPl) squarefoot to Rock layer <br /> 6.SD gpd/f tz Width <br /> 3. Calculate adsorption width ratio by dividing rock layer Faster than 0.1• Coarse Sand --- <br /> 0loading rate of 1.20 gpd/ft2 by allowable soil loading rate; 0.1.1 1 to s Sandn 1.20 2.00 <br /> oS•• Fine San0.60 2.00 <br /> 6 to 15 Sandy Loam 0.79 1.52 <br /> 1.20 gpd/ft2-1- OS0 gpd/ft2= Z . dk--0 . 16to 0m ° 2.00 <br /> 315 Silt 06 00 <br /> Check this value on page E-16. 46 to 60 Clay Loam OAS 2.62 <br /> 60 to 120 Clay 0.24 5.00 <br /> 4. Multiply adsorption width ratio by rock layer width to get sto.201., n clay - <br /> required adsorption width; - <br /> 2.'to x 10 ft =24- ft <br /> 1 <br />