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+ RECOMMENDED DESIGN CRITERIA FOR SEPTIC TANK EFFLUENT PUMPS <br />► <br /> 038 . (STEP) SEWAGE SYSTEMS <br /> D► A. Septic Tank <br /> 0 1 . Use two-compartment tank, sized and constructed in accordance with <br />► <br /> sewage regulations. <br /> 2. Extend access manhole above sanitary tee to ground surface. <br /> B . Pump Tank <br /> 1 . Tank must be large enough to provide: <br /> - 12 inches of pump submergence, minimum; <br /> • <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 /> This may include septic tank freeboard capacity, if effluent will <br /> remain below ground and below building drain outlet invert. <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 /> 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 /> 5. Tank access riser must extend at least six inches above finished grade. <br /> 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 /> D. Aires 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 /> • <br />