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SEPTIC TANK Septic tanks store the accumulated sludge, scum and effluent(clear zone)volumes, which in turn affect treatment of nitrogen within the tanks. In the following calculation,the pump-out interval factor times the QAVE times the peaking factor(PF)correlate the pump-out time interval in years with the recommended tank capacity. The peaking factor value for this project is estimated to be 2.5. Septic Tank Capacity Based on Pump-out Interval of One Year: Recommended tank capacity for a potential pump-out interval of three years after complete build-out: 2.8(pump-out interval factor)(QAVE)x Peaking Factor(PF=2.5)=2.8 (144 gals/day)x 2.5 = 1,008 gals. Total septic tank capacity= 1,200 gallon tank. Detention Time: Detention Time= 1,200 gal total tank capacity x 0.70(30%volume lost to sludge/scum accumulation) 2.5 (Peaking factor)x 144 gals/day(ADF) Detention Time=2.3 days. The minimum acceptable detention time is 1.0 day. PRESSURIZED FILTER BED SIZING CALCULATIONS BASED ON SAN JOAQUIN COUNTY SEWAGE MNDARDS Base Tank Capacity= 1,200 gal. ADF= 144 gpd Leachline Equivalent Requirement= 1,200 gallons BTC+ 144 ADF x 0.20 Sand Soil Factor(SF)at soil- effluent interface=269 lineal feet of leachline(LFLL). 269 x 3 (Silty Sandy Soil-Filter Bed Soil Factor)_ 806 sq.ft.filter bed area required. Due to the extraordinarily high sand content underlying the filter bed areas,engineered fill material will have to be imported into these areas. This will be discussed in the "Conclusions Section"of this report. Proposed: Two Filter Beds with a p"Tex pump system-Alternating between each bed: —--- Sin le Filter Bed Size=40 ft E- Long x l0 feef N-S Width=400 sq. ft.x 2 filter beds 800 sq. ft. Single � Each Filter Bed: 10 Infiltrator Chambers long x 4.0 ft effective length/chamber=40.0 ft E-W 3 Infiltrator Chambers wide x(2.83 ft+0.5 ft spacer)=3.33 ft width/chamber = 10.0 ft N-S. Total Number of Chambers= 10 Chambers long x 3 Chambers width=30 Chamber x 2 Filter Beds=60 Quick 49 Standard Infiltrator Chambers required. 100%Reserve Replacement Area: The reserve area is also divided ' o separ to filter beds. As illustrated on the Site Plan,the area that is proposed for RV par ' g Lremoved, d as 10�o replacement. In the event of system failure,the asphalt in this parking area will have�J and the r placement system installed. The auto parking area will remain as planned. Transp pprim field may be stubbed- out to these two reserve areas. Reserve replacement area dimensio 20 ft=400 s.f.each x 2= 800 s.f.,which will be equivalent to the primary filter bed area of 800 s.f. -- 13 Chesney Consulting