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' • MOUND DESIGN WORK SHEET(For Flows up to 1200 gpd) <br /> A. Average Design FLOW O 'P ST- SA*IOWA A-1: Estimated Sewage Flows in Gallons per Day <br /> f'00V- S nowt - 517... f-og- ►Jam' <br /> Estimated r)4 a gpd (see figure A-1) bedrooms Class I Class II Class III Class IV <br /> or measured — x 1.5 (safety factor) = — gpd 3 3350 22255 28 of 0 % <br /> 4 600 375 256 values <br /> B. SEPTIC TANK apacity 5 750 450 294 in the <br /> 6 900 525 332 Class I, <br /> aa*N- 7 1050 600 370 II,or III <br /> /' $' Gilkasteer lions (see figure C-1) ¢r6 8 1200 675 408 columns. <br /> p erli Pct 4' . Arm • Tank G]: Septic Capacities fin*Inns)C. OI (refer to si ova uationl�' <br /> Number of Minimum LiquidLiquidcapacitywith Liquid capacity <br /> 1. Depth to restricting layer= AttrAvuohaN.feet <br /> Bedrooms Capacity9 � withft jisposal& <br /> 2. Depth of percolation tests= v.v. feet so a 2orless 750 1125 1500 <br /> 3. Texture Loy4wt '0 Lt-44 t.614w1 3 a a 1000 1500 2000 <br /> 5 or6 1500 2250 3000 <br /> Percolation rate 7.S mpi 7,8 or 9 2000 3000 4000 <br /> 4. Soil loading rate .4.‘ gpd/sqft(see figure D-33) <br /> 5. Percent land slope S % opu•47►t. <br /> D. ROCK LAYER DIMENSIONS <br /> 1. Multiply average design flow (A)by 0.83 to obtain required rock layer area. <br /> 0 gpd x 0.83 sqft/gpd = (40 a a sqft <br /> 2. Determine rock layer width= 0.83 sqft/gpd x linear Loading Rate (LLR) <br /> 0.83 sqft/gpd x_ 11--, gpd/sqft= . I 0 ft Mound LLR <br /> 3. Length of rock layer= area+width= <br /> 49 as sqft(D1) + _IQ_ft (D2) =__(0:ti 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 /> Co a?. sqft x 1 ft= `A cuft <br /> 2. Divide cuft by 27 cuft/cuyd to get cubic yards <br /> (oaa. cuft +27 cuyd/cuft= a3 cuyd <br /> 3. Multiply cubic yards by 1.4 to get weight of rock in tons <br /> 23 cuyd x L4 ton/cuyd = 32. tons <br /> D-33: Absorption Width Sizing Table <br /> F. SEWAGE ABSORPTION WIDTH Percolation Rate Loadingto <br /> in Minutes per Soil Texture Gallons Absorption <br /> Inch per dayper Ratio <br /> (MPI) aouare foot 1 <br /> Faster then 5 Coarse Sand 1.20 1.00 <br /> Medium Sand <br /> Absorption width equals absorption ratio (See Figure D-33) Loamy <br /> a Sand <br /> 6 to 15 Sandy loam 0 79 1.50 <br /> times rock layer width (D2) 6:0 150 <br /> 0 �,,�� 2.00 <br /> 31 toy Sean g:s� 2.40 <br /> Silt <br /> ae%O f-1/ x 10 ft= 400r) ft 46 to 60 Sandy say Loam 0.45 2.67 <br /> Siltyy say Loam, <br /> 17cy1aam <br /> 61 to 120 Silty Clay 0.24 5.00 <br /> Sandyy avClay <br /> Cl <br /> Slower than 120• <br /> *System designed for these soils rout be other or perromuaee <br />