b'STORMWATERCATALOG SIZINGand extends up to the access cover. The pumps can beIn order to size a Lift Station unit, two main factors must be lifted by a portable or permanent hoist for non-confinedconsidered:space removal and replacement.Pump Selection: the operation point of the pump must be Control Panels with Level Control Equipment: calculated, this variable is directly related to total dynamic The PumpTrooper relies on an electrical control system tohead and volume capacity. There are several charts monitor the liquid level to operate the pumps. The controlsavailable to estimate this variable.PUPMU PMPU PMPLIFLTI FSTLT IASFTTIA OSTTNIOASTNISONSinclude a control panel mounted above ground plus multiple float switches located in the wet well. The controlWet Well Sizing: Once the proper pump has been panel should be weatherproof for outdoor usage. Theselected, we are able to determine what type and size of panel contains pump disconnects, starters with overloadwet well is needed. There are two types of wet wells that protection, hands-off automatic selectors, and alarmParkUSA uses for lift stations, round and rectangular. systems to indicate high liquid level conditions. Round wells have the benefit of reduced material costs as well as strength properties. A wet well for a submersible Shut off Valves, Check Valves, and Piping: pump is generally located below grade. Buried wet wells The submersible lift station has at least one inlet piperequire strength and corrosion resistance making precast where wastewater enters the wet well. When the liquidconcrete the primary choice. level rises to a predetermined level, the pumps are activated. The liquid passes through the pump impellerFor wet wells above grade, steel and fiberglass are the and is forced through the discharge pipe and into therecommended material. To summarize when determining sewer. A check valve and a gate valve are implementedthe size of the wet well, we must find the minimum on each discharge line to prevent backflow, and to allowstorage volume. Flow rate and retention time are basic isolation of each pump for servicing. These valves arevariables to do this calculation.usually located in the wet well where the discharge piping is two inches or less. When the piping is three inches orMAINTENANCElarger, an external valve pit assembly may be required.To ensure the Lift Station operates properly, routine OPERATION inspections and preventive maintenance should be performed to prevent expensive repair problems, spills, etc. Sanitary wastewater or storm water enters the wet-wellThe common routine activities to follow are:basin through the inlet pipe. An electric liquid level control system monitors the water level and engages the pump(s) The unit should be inspected weekly, but based on model at pre-determined levels. The pumps then transfer theand location, inspections may be required more often.liquid up and out of the wet-well basin into the sanitary or Records must be maintained for each of the routine storm sewer system.inspections. Logs and physical records are useful inthe long run.DESIGN CONSIDERATIONSWet well should be pumped out and cleaned at leastDepending on the project, the number of submersibletwice a year.pumps, as well as the valve system, are subject to change. Inspections of pumps are required quarterly.In smaller stations, there can be one submersible pump Inspection of check valves are required twice a year.and the valve assembly is housed within the wet well to save infrastructure cost. In larger stations, which can house Cleaning of floats are necessary four times a year.multiple submersible pumps, it is recommended that Inspection of the alarm system is required weekly.the valve system be housed in a separate valve vault. This Amp and vibration readings should be taken at least makes it easier to conduct maintenance when necessary. once a month. Annual inspection of the complete control systemis required.INFO@PARKUSA.COM|888-611-7275|WWW.PARKUSA.COM 21'