WASTEWATER
SELECTION CONSIDERATIONS
FOR WASTEWATER PUMPS
By Annabelle Powell, Journalist, Pump Industry Magazine
Pump systems are critical to keeping our world in motion. When selecting a wastewater pump, there are key factors to consider to ensure maximum efficiency and longevity, and to reduce long-term costs.
W
astewater pumps are used in the collection of sewage, effluent, drainage and seepage water. When selecting a wastewater pump, whether for a new system or replacing an old one, there are selection criteria to consider that can make big differences in performance, reliability and cost-saving energy efficiencies. This checklist includes liquid, flow rate, temperature, altitude and lifecycle costs. Industrial applications come with many demands, such as resisting corrosive chemicals and handling high temperatures. Considering such demands as well as the application environment is crucial when selecting the most suitable pump for your application. Determining these factors and selecting the right wastewater pump result in less maintenance, higher efficiency and long-term cost savings.
Different types of pumps
There are two main types pumps used for wastewater: • Conventional wastewater pumps: These are also known as non-clog, solids handling or dry-well pumps. Their main purpose is to pump liquids that contain soft solids and other stringy material. They don’t require frequent servicing and cleaning, and operate without plugging. They can either be installed with horizontal or vertical mounting.
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• Submersible pumps: These are non-clog pumps that are immersed in the wastewater for operation. They come equipped with powerful motors and are installed directly in the wet well. This means wastewater pumping stations that use submersible pumps don’t require a dry well. The pumping system construction above the ground is minimal, and all that’s visible above the surface is a concrete slab and a small housing construction for the control centre.
Pump capacity
A good first step when selecting a wastewater pump is to examine the application’s hydraulic characteristics. In choosing the right pump it’s key to accurately estimate the capacity that is required. Reviewing the required flow rate and pipe size determination will make it a simple matter to estimate and graphically display these characteristics with a system curve specific for the application. In order to create the system curve, two basic elements are required: static head and friction loss. Once the system curve is known, it is easier to determine the best pump for that application.
Fluid characteristics
The type of material in the fluid is a key consideration when selecting a wastewater pump. Fluid streams in wastewater
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