SU0011318 SSNL - Laserfiche WebLink

Home Browse Search

B. SEPTIC TANKS Septic tanks store accumulated sludge, scum and effluent(clear zone)volumes, which in turn affect treatment of nitrogen within the tanks. Detention time will be individually calculated for the two new tanks to be installed, and demonstrates that when the Max ADF is applied to each tank,there remains sufficient detention time: Detention Time Calculation for the two new septic tanks: Detention Time=22,000 gai tank capacity x 0.70 (30%volume lost to sludge/scum accumulation) 2.5 (Peaking factor)x 512 MAX gals/day(ADF) Detention Time= 1,200 gal tank capacity x 0.95 (5%volume lost to sludge/scum accumulation) 2.5 (Peaking factor)x 512 MAX gals/day(ADF) Detention Time= 1.0 days for the 2,000 gal tank and 0.9 days for the 1,200 gal tanks to be installed. The minimum acceptable detention time is 1.0 day. Although the 1,200 gallon tank has a slightly lower acceptable detention time,this is acceptable. C. PRESSURIZED FILTER BED SIZING CALCULATIONS Base Tank Capacity(BTC)= 1,200 gal. Leachline Equivalent Requirement= 1,200 gallons BTC +512 ADF x 0.250 clay Soil Factor(SF) =428 lineal feet of leachline (LFLL) required. 428 x 4 (Clay Soil - Filter Bed Soil Factor) = 1,712 ftZ filter bed area required. The Acceptance Rate was determined to be 0.190 gallons/ftZ/day. Taking a max ADF of 512 gals/day_ 0.190 gals/ft2/day=2,695 ftZ filter bed area required. The primary filter bed design area is 39 ft N-S and 57 ft E-W= 2,223 ftZ. The total (both primary and replacement) disposal area is constrained by a fence to the south, a concrete walkway to the east, an asphalt driveway to the west and a concrete foundation to the north. D. DESIGN AND OPERATIONAL SPECIFICATIONS OF THE PRESSURIZED DISPOSAL SYSTEM Pump Chamber to Filter Beds: The second compartment of the 1,200 gallon tank will be the pump, or dosing chamber for the filter bed. Orenco BioTube®ProPackage Filter Pump Vault PN: PVU57-1819 with Duplex Effluent Pump System: PN: PF5005, '/2 HP, 50 gpm, 115 Volt contained within BioTube Pump Vault. Total effluent volume can be calculated by checking pump cycle times on the panel and also to ensure both pumps are distributing effluent equally. Pressurized effluent to travel in Sch. 80 PVC 2.0" dia. Laterals for the Filter Bed: Sch. 40 PVC 2.0" dia., 1/8" orifice directed at 12 o'clock with orifice shields, 5.0 ft spacing and 39 ft long. Install clean-outs at the end of each lateral and at the end of manifold, and to be contained within Christy boxes. Page -9- Chesney Consulting