Installation of 6th Screw Pump as part of capacity upgrade at Ringsend WwTW
Uisce Éireann
Upgrade
Dublin, ROI
In 2016, Uisce Éireann commenced a significant upgrade to the existing Wastewater Treatment Works (WwTW) at Ringsend, the largest wastewater treatment works in Ireland. The overall scope of the Ringsend Upgrade Project is to increase the treatment capacity at the plant to 2.4m PE.
In January 2024, CAW was awarded the contract to install a 6th screw pump to enable the flow to the site to increase by 20%, increasing the Full Flow to Treatment (FFT) for the Works from its original design of 11.1m³ /sec to 13.8m³/sec. The number of screws in operation at any time varies depending on the influent flow rate to the works.
Project Highlights
The installation and commissioning of the sixth screw pump, which will increase the Work’s capacity to treat flows of up to 13.8m³ /sec with five pumps in operation and one on standby, was completed in February 2025, delivered on time and within budget.
As the Operations and Maintenance (O&M) Contractor at Ringsend WwTW, CAW will continue to manage the performance and maintenance of this latest asset at the Ringsend WwTW as part of its overall responsibilities as the O&M Contractor.
Project Scope
The scale and complexity of this supply and installation Project required meticulous management and planning to ensure that the installation was delivered safely on time and with minimum disruption to the ongoing Operations at the Ringsend Works.
The Scope of the Project included:
- Provision and installation of a sixth Archimedes screw pump (Ø2700 mm, Q = 2,775 m³/hr) complete with high-efficiency motor and gearbox, matching the existing 5 duty units;
- Further enhancements including water-in-oil sensor, upper and lower maintenance-free bearings, and elimination of lubrication pump;
- Advanced works including isolation of Bay F, removal of existing access covers and walkway, and pressure washing of the trough;
- Civil works comprising the installation of concrete plinths and upstands using a custom-mould system, and provision of support bracing to suit design specifications;
- Mechanical works including installation and alignment of the screw, motor, gearbox, ECO bearings, and coupling all delivered by the deployment of a 200T mobile crane;
- Electrical upgrade of MCC1 Cubicle 30A, including new VSD (160 kW), backplate, fan/filter arrangement, and full cable containment and terminations for power and control;
- Instrumentation, Control and Automation works including PLC and SCADA updates to enable operation of 6 screw pumps (5 duty + 1 standby), with full status, alarm, and control integration;
- Testing and commissioning of mechanical and electrical systems, including alignment checks, drive programming, and load testing.
Ahead of the installation of the 6th Screw Pump, CAW carried out preparatory works on parts of the inlet screw pump structures to remediate sections of concrete which had been significantly degraded due to the presence of H₂S. These remediation works involved removing the existing degraded concrete and replacing it with new concrete that incorporated steel reinforcement and additional H₂S protection.
A unique system called hydro demolition was deployed using high-pressure water to jet H₂S-infected concrete material off the structures. The process and its results can be seen below:
Following preparation, the concrete walls were treated with Cemprotect to prevent future H₂S infection and concrete degradation. The new Screw pump assembly was procured from Landustrie Water Treatment Solutions and delivered to the Ringsend WwTW ahead of the final concrete screeding of the 6th Screw Pump trough.
The 9-tonne screw (Screw F) was lifted into place within a curved mould, positioned in the Screw Pump trough ahead of pouring the concrete screed into the trough. The screw was installed and supported using temporary cross beams and props, allowing the surrounding concrete to be poured in three separate lifts to prevent uplift.
Once the concrete screed had set, the screw and mould were removed, ensuring a high-quality finish to the surrounding structure. The screw was then reinstalled and fitted with splash guards, followed by final alignment, and installation of the gearbox and motor.
With the gearbox-to-motor alignment completed, the new Screw F was mounted onto its concrete plinth and commissioned, now operating alongside the existing Screw A.
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