SU0011022 SSNL - Laserfiche WebLink

Home Browse Search

IV. SEPTIC SYSTEM OPERATIONAL PARAMETERS AND COMPONENTS A. PROPQSED SEPTIC SYSTEM SSS§ 3.77.. The design of the pressurized filter bed disposal system is based upon the factors for efficient operation, disposal field longevity, and environmental protection. An overview of the system operation to serve the existing building is as follows: The existing septic stank has been directly observed to be structurally sound. An influent line from the restroom connects to this plastic tank. Effluent from the two-compartment tank will gravity to a pump basin that will house a duplex high head pump system. The pump system will pressurize the effluent for both transport and disposal in the filter bed. Pumping will be on-demand and not timed- dose. The filter bed will be constructed directly to the north of the existing Building. Effluent will be pressurized through three laterals for equal distribution oriented within the filter bed disposal arrangement. The 100%reserve replacement area is denoted on the Site Plans and is directly west of the primary filter bed. B. SEPTIC TANK Septic tanks store accumulated sludge, scum and effluent(clear zone) volumes, which in turn affect treatment of nitrogen within the tanks. Detention time calculations demonstrate that when the Max ADF is applied to the existing tank,there remains sufficient detention time: Detention Time Calculation: Detention Time=750 gal tank capacity x 0.70(30%volume lost to sludge/scum accumulation) 1.5 (Peaking factor)x 64 MAX gals/day(ADF) Detention Time=5.5 days. The minimum acceptable detention time is 1.0 day. C. PRESSURIZED FILTER BED SIZING CALCULATIONS Base Tank Capacity(BTC) = 1,200 gal. Leachline Equivalent Requirement= 1,200 gallons BTC +64 Max ADF x 0.225 clay loam Soil Factor (SF) =284 lineal feet of leachline (LFLL) required. 284 x 3.5 (Clay loam Soil - Filter Bed Soil Factor)= 995 ftZ filter bed area required. The primary filter bed is proposed to be 10 ft wide N-S and 80 ft long E-W. Page -8-