Change of Pump Delivers Success on Digester Tank Clearance
Project Overview
Change of Pump Delivers Success on Digester Tank Clearance
The Cleaning Team at this wastewater treatment company improved digester clearance operations by switching pump technology. This resulted in minimal blockages, less ragging, and an 80% reduction in maintenance and wear-part replacement.
Challenge
The cleaning team leader at this wastewater company wanted to improve performance in their digester clearance duties. A well-known brand of progressive cavity pump had been chosen but was struggling with rag and abrasive solids that collected at the bottom of the tanks.
The problems identified:
- Pumping heavy grit and solids causes high wear on the stator and rotor, reducing pump efficiency.
- Large amounts of rag are entrained, causing downtime for pump unblocking.
- Operation often requires the pump to run dry, causing mechanical seal failure.
- Rapidly rotating parts in the pump are becoming entangled with rags, causing the pump to fail frequently.
The high wear rate, pump tripping (due to blockages and high rag content), and frequent downtime for stator and rotor replacement or de-ragging were putting the staff and TOTEX budget under pressure.
Solution
An LSM peristaltic pump from Atlantic Pumps was trialled and proved successful in removing the limitations of the incumbent pump.
The new pump comfortably handled the sludges at 12% dry solids, including rag and grit. The model used has a 150mm clearance, reducing shear, wear, and risk of blockage. Should an inlet blockage occur, the pump can be reversed to push back into the tank.
Running at 20rpm vs 250rpm of a progressive cavity pump, the new pump has an increased wear life of around 10x.
It features strong suction, large-diameter rollers, no rotating parts in the sludge stream, and is inherrently dry-run safe. The dry-run capability is particularly advantageous for clearing tanks of heavy sludge that doesn’t seep or flow easily.
Results
💦 80% reduction in spares usage 💦 Minimal downtime for pump repairs 💦 Minimal pipe unblocking
The new pump more than meets current needs – at full speed, it exceeds the capacity of most screening units in use today. As a result, these pumps can be set at the best flow rate to match the screener’s requirements. This future-proofs the pump asset, while delivering immediate energy and maintenance savings.
“The main benefit of the new pump type is reduced blockages, no stator wear and good self-priming ability” – Cleaning Team Lead, Northern England Water Company.
- Strong suction – self-priming even with low-seepage/high viscosity sludge.
- Can safely run dry – the pump hose and rollers are contained in a lubricant for maximum protection and efficiency.
- Maximum solids passage is only limited by the internal pipe diameter, 150mm in this case.
- Self-sealing against backflow, and reversible.
- Wide rollers and slow rotation mean very low wear and higher efficiency.
- No rotating parts in the sludge, avoiding rag weaving in the pump.
Following this successful trial, the water company have ordered multiple units of different sizes for use in similar duties across their network.
“The main benefits of this pump are reduced blockages, no stator to wear, and it’s self-priming capabilities”
Cleaning Team Leader, Water company
Looking to improve pump reliability and reduce TOTEX at your sludge treatment facility?
To discuss sludge pumping solutions for your application, speak to Mark McCreadie, Atlantic Pumps.
