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MOUND DESIGN WORK SHEET(For Flows up to 1200 gpd) <br /> A. Average Design FLOW A-1: Estimated Sewage Flows In Gallons per Day <br /> number of <br /> Estimated y. O gpd (see figure A-1) bedrooms Class I Class II Class III Class IV <br /> or measured x 1.5 (safety factor) = gpd 2 300 22255 180 260% <br /> e <br /> 4 600 375 256 values <br /> B. SEPTIC TANK Capacity 5 750 450 294 in the <br /> 6 900 525 332 Class I, <br /> -/�ogallons(see seefigure C-1) 7 1050 600 370 oII,01111 <br /> a <br /> 8 1200 675 408 columns. <br /> C. SOILS (refer to site evaluation) G1: Septic Tank Capacities(In Milan) <br /> ty <br /> Number of Minimum Liquid Liquid i with Liquid <br /> ' r 'o Bedrooms Capacit). PAW disposal withlift <br /> insided& <br /> 1. Depth to restricting layer= �.V 4 �.1 feet 1 1 a � <br /> 2. Depth of percolation tests= 1. 0 feet 2 or less 750 1125 1500 <br /> 3. Texture 1A- L414-w1 3 or a <br /> 1000 1500 2000 <br /> 5 or 6 1500 2250 3000 <br /> Percolation rate a o. 0 mpi 7,8 or 9 2000 3000 4000 <br /> 4. Soil loading rate .4S gpd/sqft(see figure D-33) <br /> 5. Percent land slope I a % <br /> D. ROCK LAYER DIMENSIONS <br /> 1. Multi ly average design flow (A)by 0.83 to obtain required rock layer area. <br /> gpd x 0.83 sqft/gpd = 31 4 sqft <br /> 2. Determine rock layer width= 0.83 sqft/gpd x linear Loading Rate (LLR) <br /> 0.83 sqft/gpd x )a. gpd/sqft= 10 ft Mound LLR <br /> 3. Length of rock layer= area+width= <br /> 9 sqft(Dl)+ J_ft (D2) = 3 '3 ft < 120 MPI <12 <br /> E. ROCK VOLUME > 120 MPI < 6 <br /> 1. Multiply rock area (Dl)by rock depth of 1 ft to get cubic feet of rock <br /> 3 Ti sqft x1ft= 30y cult <br /> 2. Divide cuft by 27 cuft/cuyd to get cubic yards <br /> Z 0 4 cuft +27 cuyd/cuft = 14 cuyd <br /> 3. Multiply cubic yards by 1.4 to get weight of rock in tons <br /> 3/4 cuyd x 1.4 ton/cuyd = tons <br /> ',D-33: Absorptlon Width Sizing Table <br /> F. SEWAGE ABSORPTION WIDTH Percolation Rate Loading Rate <br /> in Minutes per Soil Texture Gallons Absorption <br /> Inch per day per Ratio <br /> (MP1) square foot <br /> Faster than 5 Coarse Sand 1.20 1.00 <br /> Medium Sand <br /> Absorption width equals absorption ratio (See Figure D-33) Loamy Sand <br /> Fine Sand <br /> 6 m 15 Sandy Imam 0 79 1.50 <br /> times rock layer width(D2) 6 2.00 <br /> n 1 to2 sir.. 8: 2.40 <br /> in <br /> .;.(.09 x 10 ft= L.r / ft 46 to 60 SanryddC a Loam <br /> m 0.45 2.67 <br /> Sil(]ay barn <br /> 61 to 120 Silty lay 0.24 5.00 <br /> Clay <br /> Slower than 120* <br /> *System desiprd for are.oils mw be adieux perfemrnee <br />