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. . _ i1,5 <br /> 131 <br /> 4 RECOMMENDED DESIGN CRITERIA FOR SEPTIC TANK EFFLUENT PUMPS <br /> . (STEP) SEWAGE SYSTEMS <br /> 0 <br /> 0 A. Septic Tank CI PA <br /> 1 . Use two-compartment tank, sized and constructed in accordance with <br /> sewage regulations. <br /> 0 <br /> 2. Extend access manhole above sanitary tee to ground surface. <br /> i B. Pump Tank <br /> 1 . Tank must be large enough to provide: <br /> ♦ - 12 inches of pump submergence, minimum; <br /> - 3-minute minimum pump run time (15 gallon per minute minimum pump flow <br /> - rate) ; <br /> - full day of emergency storage capacity above high-water alarm on level . <br /> 0 This may include septic tank freeboard capacity, if effluent will <br /> remain below ground and below building drain outlet invert. <br /> 4 <br /> 2. Tank must be sealed, watertight tank (fiber glass or one-piece, precast- <br /> septic tank or special provisions for assuring watertight tank indicated) . <br /> 4 3. Anti-buoyancy provisions must be adequate. <br /> 4. ; All pipe and wire conduits into tank must be through hubs or fittings <br /> made during the construction of the tank and installed in a watertight <br /> and gastight fashion. <br /> 4 5. Tank access riser must extend at least six inches above finished grade. <br /> 4 C. Pump <br /> 1 . Must be an effluent pump capable of delivering at least 15 gallons per <br /> minute at the expected total dynamic head at each station. <br /> 2. All pumps in a single STEP system-must be the same model and size. <br /> 3. Pumps must be activated by mercury level control switch(es) . <br /> 4. Pump discharge pipe must be of Schedule 40 PVC, or stronger material , <br /> and include a check valve, disconnect union, and gate valve within the <br /> pump tank. Pump must be readily removable from the ground surface. <br /> y D. Wires must be conveyed to a watertight (NEMA 4X) , outside, vandal-resistant <br /> junction box through waterproof and gasproof conduits, with no splices <br /> made inside the lift station. Junction box may be mounted on the outside <br /> of the lift station riser above the ground surface. <br /> 0 <br /> 9 <br /> 4 <br /> 4 <br />