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, ' RRETR�ATMENT WORK SHEET A•1 Estimated Sewage Flows in GPD 1. FLOW Bedrooms Class I Class il Class III Class IV A. Estimated 300 gpd(see figure A-1) 2 300 225 180 60%of � measured x 1.5(safet factor= 0 gpd 3 450 300 218 the B. SEPTIC TANK CAPACITY 2,000 gallons(see figure C-1) 4 600 375 256 values a �5u 4ou �y4 in cne 1 2. SOILS(Site evaluation data) 6 900 525 332 Class I, C. Depth to restrictin la er= 24"-35" feet 7 1050 600 370 II or II D. Texture LoamlCla Loam Percolation rate 28.2 MPI 8 1200 675 408 columns E. SSF 1.67 ftZlgpd(see downsizing or<3ff figure) � F. Land Slope 10 to 12 % C-1 Se tic Tank Ca aci in Gallons Number of Minimum Capacity with Capacity with 3. Pressure Distribution Trench Bottom Area Bedrooms Ca acit Garb.Disp. Disp.and Lift H. For trenches with 6"of rock below the pipe,Area=Flow(1A)divided by SSF(2E)= 2 or less 750 1125 1500 ' 300 gpd x 1.67 ft2lgpd= 501.0 ft2 3 or 4 1000 1500 2000 I. For trenches with 12"of rock below the pipe,Area=Flow(1A)divided by SSF(2E)x 0.8 5 or 6 1500 2250 3000 300 gpd x 1.67 ftZlgpd x 0.8 = 400.8 ft2 7,8 or 9 2000 3000 4000 � 4. ORGANIC LOADING(if pretreatment is being used) J. 1. Organic loading=flow(A)x estimated BOD in mglL leaving the Downsizing Chart with 3 ft of Separation pretreatment unit x 8.35 I 1,000,000 Soil Characterisitcs,SSF 8 Or anic Loadin � 300 gpd x 10 mglL x 8.35 I 1,000,000= 0.02505 Ibs BOD Perc Rate Soil Tecture SSF Organic Ld 2. System loading=organic loadin J1 I area(H or I) mpi s ft/ d Ibslda Ift 0.02505 Ibs BOD I 401.0 ft2 = 6E-05 <0.1 Coarse sand 0.83 0.0020 , 3. Check system loading rate on chart. Should be less than value. 0.1-5 Medium sand 0.83 0.0015 Loam sand 5. ROCK VOLUME 0.1-5 Fine sand 0.83 0.0012 K. Rock depth below distribution pipe plus 0.5 foot times bottom area: 6-15 Sand loam 0.83 0.0011 � _(Rock depth+0.5 foot x Area(H,or I) - 16-30 Loam 0.83 0.0010 (�ft+0.5 ft)x � ftZ 0 ft3 31-45 Silt loam,silt 1.00 0.0007 L. Volume in cubic yards=volume in cubic feet divided by 27 46-60 Clay loam, 1.10 0.0006 K I 27=cubic yards 0 I 27= 0 yd3 sandy clay , M. Weight of rock in tons=cubic yards times 1.4 or silt cla L x 1.4=tons 0 x 1.4= 0 tons 61 -120 Clay,sandy 2.50 0.0005 . or silt cla , 6. SYSTEM LENGTH >120 Cla 3.25 0.0003 N. Select width= �3 ft 0. Divide bottom area b width: H,I)divided by N=lineal feet Sizing Chart with<3 ft of Separation 401.0 ftZ I 3 ft = 134 lineal feet Soil Characterisitcs 8 SSF ' Perc Rate Soil Tecture SSF an oam 7. SYSTEM LlR 16-30 Loam 1.67 P, Draw a line downhill though soil treatment system drawn in layout. 31-45 Silt loam,silt 2.00 � How many trenches does it cross? Add their widths together. 46-60 Clay loam, 2.20 width 1 +width 2+width 3+...... sandy clay �3 ft + �3 ft + 03 ft + ft = 9 ft or silt cla Q. Divide total trench width(P)by SSF(F)=gallons per foot 61-120 Clay,sandy 4.00 � 9 ft I 1.67 ft2lgpd = 5.4 gallft(Should be<12 gallons per loot) or silt cla >120 Cla 5 ' , ' � Page 1 of 1 '