Agenda - 05-22-1989 - Laserfiche WebLink

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