Increasing UV Treatment Capacity and Energy Efficiency at Ringsend WwTW
Uisce Éireann
Upgrade
Dublin, ROI
In April 2024, CAW commenced work on the upgrade of the UV Disinfection Plant at the Ringsend Wastewater Treatment Works (WwTW). This upgrade was necessary to improve the performance efficiency of the disinfection process corresponding to the increase of water being discharged and ultimately to improve the quality of the receiving waters in Dublin Bay.
Completed in May 2025, the project highlights CAW’s end-to-end project delivery capabilities, spanning MEICA design, civil engineering works, supply, installation, and commissioning, all carried out while ensuring that the Ringsend WwTW continued to operate uninterrupted and was able to continue to receive and treat wastewater.
During the bathing season, final effluent from Ringsend WwTW undergoes UV disinfection to enhance the quality of the water being discharged and ensure that the waters in and around Dublin Bay remain safe for public recreation. The process uses ultraviolet light to safely and effectively disinfect the treated water before discharge.
The project supports Uisce Éireann’s broader commitment to modernise Ireland’s water infrastructure, as it continues to invest in the upgrade and expansion of key water and wastewater treatment assets nationwide, including Ringsend WwTW.
Project Highlights
Project Scope
The design, build and commissioning of the UV Disinfection Upgrade was carried out in collaboration with UV specialist, Xylem, incorporating their WEDECO TAK 55 Series - a well-proven UV disinfection system with a large installation base around the globe.
CAW undertook a number of key roles in the delivery of this project, including the roles of Project Supervisor Design Phase (PSDP) and Health and Safety Coordinator.
The main components of the Scope of Works for the project included:
- Supply and installation of all mechanical and electrical equipment, including the UV modules, UV lamps, electrical cabinets, ballast cards, quartz sleeves and cabling.
- Electrical Upgrade to facilitate UV Upgrade project.
- Improvement works to the pneumatically operated wiper system.
- Replacement of monorail and lifting gantry.
- Building and civil engineering works to include the removal of blanking material in selected channels.
- Instrumentation Control and Automation Works, including SCADA Integration & modifications.
- Testing and Commissioning.
Project Delivery
To allow the Mechanical and Electrical teams to progress, a Civil Engineering Demolition crew was tasked with devising the most efficient method for removing the concrete blanking material. Utilising a hydraulic concrete splitter, they successfully fractured the concrete into manageable sections, which were then safely lifted out of the channels by crane, streamlining what could have been a time-consuming process.
The Electrical team was tasked with pulling and terminating cabling for 1,170 new UV lamps. Cable management and routing presented notable challenges during installation, requiring precise planning and execution to maintain system integrity and performance.
Mechanical works took place within the effluent outlet channel during scheduled full plant flow shutdowns. To ensure safe working conditions, over-pumping was employed to lower water levels in the channel. This critical step, combined with close coordination with the Operations team, enabled safe isolation of flows and access for the mechanical installation.
Outcome
This critical project plays a key role in maintaining high water quality standards in Dublin Bay and was delivered on time and within budget, ready for the 2025 bathing season. It also supports Uisce Éireann’s ambitious expansion programme, which aims to increase the capacity of Ringsend WwTW from 1.64 million PE to 2.4 million PE.
As part of the UV Upgrade Project, the CAW team successfully integrated the new UV equipment and upgraded infrastructure without disrupting ongoing operations, thus safeguarding both plant performance and site safety throughout delivery.
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