Submersible pumps operating in sewage, wastewater or high-solids applications are increasingly facing a common challenge: persistent clogging caused by wipes, sanitary products, fibrous materials and other non-dispersible solids entering the system.
Soft blockages and ragging issues can significantly impact pumping performance, increase maintenance requirements and lead to costly downtime. Industry research suggests that more than 60% of sewage pumping station callouts are directly related to pump blockages. In severe cases, clogging can result in complete pump failure, emergency maintenance and expensive repairs.
Fortunately, many clogging issues can be prevented through proper pump selection, system design and routine maintenance. In applications where solids, fibres and debris are unavoidable, cutter and grinder pumps can provide an effective long-term solution.
Common Challenges in High-Solids Pumping Applications
Submersible pumps can experience clogging for a variety of reasons, including:
- Excessive wipes, rags and fibrous materials entering the system
- Incorrect pipe sizing that restricts solids passage
- Low pipeline velocity allowing solids to settle
- Improper pump selection for the application
- Operating pumps outside their Best Efficiency Point (BEP)
- Inadequate screening or pre-treatment systems
- Lack of regular pump maintenance and inspection
When these factors combine, solids can accumulate around the impeller, suction plate or discharge piping, reducing efficiency and increasing wear on pump components.
Preventing Pump Clogging
While no system is completely immune to blockages, the following measures can significantly reduce the risk:
1. Select the Right Pump
Pump selection is one of the most important factors in preventing clogging. Ensure the pump is capable of handling the expected solids size, concentration and fibre content. For challenging sewage and wastewater applications, cutter or grinder pumps can reduce solids into smaller particles before they enter the discharge pipeline. Learn more about pump selection.
2. Ensure Correct Pipe Sizing
Discharge pipework should be sized appropriately for the solids being pumped. Pipes that are too small can create restrictions, while oversized pipes may allow solids to settle due to reduced flow velocity.
3. Maintain Adequate Flow Velocity
Maintaining sufficient velocity within the pipeline helps keep solids suspended and reduces sediment build-up.
4. Install Effective Screening
Strainers and screening systems can prevent large debris from entering the pump and causing damage or blockages.
5. Schedule Routine Maintenance
Regular inspections of the suction plate, impeller and pump intake help identify build-up before it becomes a major problem. Preventative maintenance is generally far less costly than emergency repairs.
Steps to Unclog a Pump Intake & Recommended Cleaning Methods
When a blockage occurs or as part of routine maintenance, follow the guide below to safely inspect, clear and maintain the pump:
- Disconnect the pump from all power sources.
- Remove accumulated solids from the suction plate and impeller during maintenance.
- Remove the pump casing and inspect pump casing and surrounding components.
- Check discharge lines for restrictions or sediment build-up.
- Flush the discharge line with clean water to remove any trapped solids.
- Reassemble the pump and test the operation.
Routine cleaning not only improves reliability but can also extend pump service life.
Case Study: BN Cutter Pump Reduces Maintenance Requirements
At the wastewater pumping station of East China University of Science and Technology, three 3.7kW BN Series submersible pumps were installed to improve domestic sewage handling and reduce maintenance requirements.
Prior to the upgrade, operators were required to:
- Clean screens daily for one to two hours
- Perform annual sedimentation tank cleaning
Following installation of the BN pumps, the site reported:
- No clogging during the first month of operation
- Elimination of daily screen cleaning
- Improved power efficiency
- Reduced maintenance workload
The project demonstrated how an effective cutter pump solution can simplify wastewater operations while improving overall efficiency.
CZ/BN Series Cutter Pumps
The CZ/BN Series features Tsurumi’s latest crushing technology designed specifically for wastewater containing solids and fibrous materials.
Key features include:
- Two rotating leading blades for improved cutting performance
- Tsurumi’s original heart-shaped stationary suction blade
- Extended rotating guide that prevents waste accumulation at the impeller centre
- Ability to cut and transfer fibrous materials efficiently
- Ductile cast iron impeller and suction cover for enhanced durability
The combination of powerful cutting action and reliable hydraulic performance makes the BN Series ideal for municipal wastewater, sewage pumping stations and industrial applications.
Case Study: C Series Eliminates Persistent Blockages
A municipal wastewater operator in United Kingdom was experiencing frequent pump blockages caused by wipes and fibrous material entering the pumping station.
The maintenance burden had increased significantly, with cleaning required several times per week.
To address the issue, a Tsurumi C Series cutter pump was installed. The pump incorporates a tungsten carbide cutting mechanism, impeller and suction plate, allowing solids and fibrous materials to be effectively cut before entering the discharge line. After several months of operation, the operator reported that blockages and clogging had been eliminated, substantially reducing maintenance requirements and improving pumping station reliability.
C Series Cutter Pumps
The C Series has been a proven solution for challenging wastewater applications for decades. Key features include:
- Tungsten carbide cutting mechanism
- Excellent resistance to wear
- Effective handling of wipes, fibres and ragging materials
- Suitable for municipal and industrial wastewater applications
- Available in multiple sizes and performance ranges
Conclusion
Clogging remains one of the most common and costly issues facing wastewater and sewage pump operators. However, many blockages can be prevented through proper system design, routine maintenance and selecting the right pump technology for the application. Where wipes, fibrous materials and other difficult solids are present, cutter and grinder pumps can provide a highly effective solution. Tsurumi’s BN Series, C Series and MQ Series pumps are specifically designed to reduce clogging, minimize maintenance requirements and improve long-term system reliability.
If you are experiencing recurring blockages or need assistance selecting the right pump for your application, contact Tsurumi Australia for expert advice and support.