Tank Cleaning Time Halved with Hire of Rag Tolerant Pump
Project Overview
Tank Cleaning Time Halved with Hire of Rag Tolerant Pump
This sewage treatment works faced recurring challenges cleansing their inlet reception balancing tank, which sit upstream of the site’s primary screens.
The cleaning process involved isolating the balancing tanks and pumping the top water to the screening unit before the actual sludge clearing could begin.
Speeding up the removal of the top layers reduced the time per cycle from 2 hours to 30 minutes.
Challenge
The inlet balancing tank accumulates significant quantities of grit, rags, and sludge, requiring 4-monthly clean-outs. This involved stopping the pumps at the local terminal pumping stations for 2-3 hours a day, requiring 10 consecutive days to remove 80 ton of Rag and Grit.
The time-consuming process was costly because the vac tank had to repeatedly load and unload the upper layers of wastewater before the sludge itself could be accessed.
With a maximum three-hour downtime window per day, operators were under pressure to complete the task in less time and at a lower cost of tanker hire. They trialled submersible pumps, but they kept getting blocked by suspended solids.
As a result, the job typically took 10 days to complete, ballooning the cost of vac-truck hire and pushing the plant to its operational limits.
The peristaltic pump helped us remove the growing volume of top water, creating a greater time frame for the tanker jetter to remove the rag and grit, before we needed to run the pumps at the local terminal pumping stations. Previously, we were wasting up to 2 hours per cycle; this was reduced to 30 minutes. We are now completing the job within 5 working days, instead of 10.
Senior operations techician, English Water Company
Solution
This wastewater company hired an industrial peristaltic pump that is specifically designed to handle primary sewage containing rag and grit, maintaining a reliable flow without clogging.
This LSM pump from Atlantic Pumps was used to transfer top water and entrained debris from the tanks three times faster than the vac truck could, freeing up more of the daily maintenance window for the actual sludge removal.
The LSM itself can pass a high amount of suspended rag and solids, negating the use of high-wearing, energy consuming macerator pumps – or submersible pumps that are prone to time-consuming blockages.
The pump’s flow-rate can be matched to the system and operational needs via model selection or VFD controller.
By emptying the inlet’s balancing tanks in a third of the time, this WwTW has halved the hire time of the tanker vacs, resulting in increased headroom for additional inflow reception from local pumping stations and a reduction in OPEX.
Results
By deploying the rag-tolerant hire pump, this STW:
- Reduced tank cleaning times by 50%
- Reduced overall costs by 25%
- Improved operational efficiency within existing maintenance windows
- Increased resilience, improved process control, and lower risk and pressure on maintenance staff.
- Achieved these benefits and savings with a week’s pump hire cost roughly equal to one day of vac tanker use.
- Reduced CO2 emissions by decreasing diesel truck use with efficient electric pumps.
The revised operational approach adopted at this WwTP has delivered immediate operational savings and established a proven, AMP8-aligned methodology for managing future tank cleans more efficiently and sustainably.
This enhanced process supports proactive maintenance planning, optimises flow capacity, and strengthens long-term asset resilience.
To discuss this case study or a similar application, please contact Mark McCreadie or Martin Gillman, Water Industry lead at Atlantic Pumps.
