b'LT ENGINEERINGCATALOGSIZINGShut off Valves, Check Valves, and Piping: In order to size a Lift Station unit, two main factors mustThe submersible lift station has at least one inlet pipebe considered:where wastewater enters the wet well. When the liquid level rises to a predetermined level, the pumps arePump Selection: the operation point of the pump mustactivated. The liquid passes through the pump impellerbe calculated, this variable is directly related to total and is forced through the discharge pipe and into thedynamic head and volume capacity. There are several sewer. A check valve and a gate valve are implementedcharts available to estimate this variable.on each discharge line to prevent backflow, and to allow isolation of each pump for servicing. These valves areWet Well Sizing: Once the proper pump has been usually located in the wet well where the discharge pipingselected we are able to determine what type and sizeis 2 inches or less. When the piping is 3 inches or larger, of wet well is needed. There are two types of wet well an external valve pit assembly may be required. that ParkUSA uses for lift stations, round and rectangular. Round wells have the benefit of reduced material costsOPERATION as well as strength properties. A wet well for a submersible Sanitary wastewater or storm water enters the wet-wellpump is generally located below grade. Buried wet wells basin through the inlet pipe. An electric liquid level controlrequire strength and corrosion resistance making precast system monitors the water level and engages the pump(s)concrete the primary choice. For wet wells above grade, at pre-determined levels. The pumps then transfer thesteel and fiberglass are the recommended material.liquid up and out of the wet-well basin into the sanitary To summarize when determining the size of the wet well,or storm sewer system. we must find the minimum storage volume. Flow rate and retention time are basic variables to do this calculation.DESIGN CONSIDERATIONS MAINTENANCEDepending on the project, the number of submersible pumps, as well as, the valve system are subject to change.To ensure the Lift Station operates properly, routine In smaller stations, there can be one submersible pumpinspections and preventive maintenance should be and the valve assembly is housed within the wet well toperformed to prevent expensive repair problems,save infrastructure cost. In larger stations, which can housespills, etc. The common routine activities are:multiple submersible pumps, it is recommended that the The unit should be inspected weekly, but based on model valve system be housed in a separate valve vault. This makesand location, inspections may be required more often.it easier to conduct maintenance when necessary.Records must be maintained for each routine inspection. Logs and physical records are useful in the long run. Wet well should be pumped out and cleaned at leasttwice a year. Inspections of pumps are required quarterly. Inspection of check valves are required twice a year. Cleaning of floats are necessary four times a year. Inspection of the alarm system is required weekly. Amp and vibration readings should be taken at leastonce a month. Annual inspection of the complete control systemis required.62 INFO@PARKUSA.COM|888-611-7275|WWW.PARKUSA.COM'