When it comes to municipal water and wastewater systems, pump selection isn’t just an engineering decision—it’s a long-term infrastructure strategy. These systems must deliver continuous performance under demanding conditions, often for decades. Choosing between a vertical turbine pump (VTP) and a submersible turbine pump (STP) is a critical step that affects not only performance, but also maintenance, cost, and efficiency.
While both pump types are widely used in municipal settings, their suitability depends on several variables: depth, flow rate, access, noise tolerance, and maintenance capability. This blog explores the advantages and disadvantages of each type, and provides a side-by-side comparison to help utilities, engineers, and system planners make informed decisions.
Overview of Each Pump Type
Vertical Turbine Pumps (VTPs)
Vertical turbine pumps are engineered for deep well applications and high-capacity water movement. Typically, the motor is located above ground, coupled via a long shaft to an impeller assembly which is submerged in the fluid. The design includes bearing spiders with line shaft bearings that help stabilize the shaft inside the column assembly, ensuring alignment over long vertical distances. VTPs are often used for raw water intake from lakes, rivers, or deep wells, as well as for clean water supply in treatment plants.
Submersible Turbine Pumps (STPs)
Submersible turbine pumps feature a rotating assembly of impellers and a shaft housed within a bowl assembly, similar to vertical turbine pumps. The key distinction lies in the motor configuration: in a submersible turbine pump, a sealed submersible motor is attached to the bottom of the pump via a motor bracket, allowing the entire assembly to be submerged in the fluid. These pumps are commonly installed in wet wells or deep sumps and are frequently used in lift stations, stormwater systems, and municipal wastewater facilities. Their submerged design reduces noise and saves space, making them particularly suitable for urban or confined environments.
VTPs vs STP Comparison: Key Advantages and Disadvantages
VTP Advantages:
VTP Disadvantages:
STP Advantages:
STP Disadvantages:
Specific Applications for VTPs vs STPs
Selecting the best pump hinges on specific operating conditions, infrastructure layout, and future scalability needs. Below are guidelines based on common municipal scenarios.
Additionally, hybrid systems may also be considered. For example, municipal systems may use vertical turbine pumps for deep well extraction, while deploying submersible turbine pumps in downstream stations such as wet wells or auxiliary lift points to meet spatial or operational needs.
Other Special Considerations for Municipal Systems
Municipal water and wastewater systems vary significantly depending on population density, geography, environmental requirements, and infrastructure age. Here are some context-driven tips:
Clean water supply applications often favor vertical turbine pumps due to their higher efficiency and reduced risk of motor contamination.
Vertical turbines offer easier motor access and above ground maintenance, making them suitable for staffed facilities. Submersible turbines, while harder to access—can’t be accessed without pulling the full assembly—, reduce noise and protect the motor from environmental exposure.
Submersible turbines can be advantageous in remote or space-constrained sites where a quiet, low-profile pump is needed. However, for high-capacity or easily accessible locations, vertical turbines may offer better efficiency and serviceability.
Consider lifecycle energy use. Vertical turbines tend to offer better efficiency at higher flows, while submersible turbines may cost less to operate at lower duty points.
Corrosive water may necessitate special coatings or materials for both types. Submersible turbines often have limited resistance to high-chloride or chemical-laden water unless specified.
Both pump types require careful planning for submergence depth and inlet conditions. STPs in particular must maintain minimum submergence to prevent cavitation—a destructive condition where vapor bubbles collapse and damage impellers and internal components. Proper well design and feed pressure help mitigate this.
Working With Experts: Evaluating Strategies For System Selection & Public Infrastructure
There is no one-size-fits-all solution in municipal water and wastewater systems. The decision between a vertical turbine and a submersible turbine pump must be driven by site-specific needs, infrastructure layout, environmental factors, and long-term planning priorities.
Vertical turbine pumps excel in deep-well, high-flow systems with dedicated above-ground infrastructure. Submersible turbine pumps offer flexibility, compactness, and easier installation in confined spaces. Ultimately, your choice should be grounded in a clear understanding of your application and lifecycle goals.
Not sure which pump type fits your municipal system best?
Contact Kinetiflo today for a personalized consultation and pump system design evaluation. Our experts can help you make the right decision for performance, reliability, and budget.
