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MOUND DESIGN WORK SHEET (For Flows up to 1200 d) <br /> A. Average Design FLOW A-1: Estimated Sewage Flows in Gallons per Day <br /> number o <br /> Estimated 7S0 gpd (see figure A-1) bedrooms Class I Class II Class III Class IV <br /> or measured x 1.5 (safety factor) = gpd 2 300 225 180 60% <br /> 3 450 300 218 of the <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 /> 9-;t-5-0 gallons (seefigure ure C-1) 7 1050 600 378 II, or III <br /> a- <br /> g f g 8 1200 1 675 408 columns. <br /> C. SOILS (refer to site evaluation) C-1: Se tic Tank Capacities(in allons <br /> Number of Minimum Liquid Liquid capacity,with Liquid capacity <br /> Bedrooms Capacity garbage d sptyosal with disposal& <br /> 1. Depth to restricting layer = �o S' feet lift inside <br /> 2. Depth of percolation tests = 1.0 feet 2 or less 750 1125 M <br /> 3. Texture /oAw+ 3 or 4 1000 1500 20005 orb 1500 2250- 3000 <br /> Percolation rate�_mpi 7,8 or 9 2000 3000 <br /> 4. Soil loading rate .fid gpd/sqft(see figure D-33) <br /> 5. Percent land slope S % <br /> D. ROCK LAYER DIMENSIONS <br /> 1. Multiply average design flow (A) by 0.83 to obtain required rock layer area. <br /> 26D gpd x 0.83 sqft/gpd = Gan sgft <br /> 2. Determine rock layer width= 0.83 sqft/gpd x linear Loading Rate (LLR <br /> 0.83 sqft/gpd x /, gpd/sqft= /0 ft Mound LLR <br /> 3. Length of rock layer = area=width = <br /> Lao sgft(D1) _ .v ft (D2) = 6 ft < 120 MPI < 12 <br /> E. ROCK VOLUME > 120 MPI < 6 <br /> — — t <br /> 1. Multiply rock area (D1) by rock depth of 1 ft to get cubic feet of rock i <br /> (,acs sgft x 1 ft = 42o cuft <br /> 2. Divide cuft by 27 cuft/cuyd to get cubic yards <br /> (oa•o cult =27 cuyd/cuft = .23 cuyd <br /> 3. Multiply cubic yards by 1.4 to get weight of rock in tons <br /> aZ cuyd x 1.4 ton/cuyd = 33 tons <br /> D-33: Absorption Width Sizing Table <br /> F. SEWAGE ABSORPTION WIDTH P..«'M nti, Falc• l w 211 Haic <br /> w�1mulc>i•.^ tiva lcttwc Gallon. Abaurjx-t <br /> In.tI flit.lav IK•t Haft. <br /> quaw 1—t <br /> i'a.tcr that <br /> Ah•diurn S.uid <br /> Absorption width equals absorption ratio (Sec Figure D-33) _ `"ant 1 lti°son`' <br /> _ a;l114_ <br /> times rock layer width (D2) <br /> 11 u,a - bit carom 0 50 2 4( <br /> _ _.._ ___511L—_ _-- _-___5--_- <br /> �0 x f t = V f t 4r�to Olt Sarrly Clay iAan 0.45 b' <br /> SlItY Ciao Iwram <br /> _ _�•i:1X1N:ulL_ - --- -- <br /> 61 <br /> Sand.Ch, <br /> (oar <br />