Irish Water has been granted planning permission for the Ringsend Wastewater Treatment Plant upgrade project - the plant treats approximately 40% of Ireland’s public wastewater.
The plant is currently operating over capacity and is not in compliance with the EU’s Urban Wastewater Treatment Directive. Although it was designed to cater for an equivalent of 1.64 million people, it currently treats wastewater for the equivalent of 1.9 million people serving Greater Dublin and surrounding areas.
The planned upgrade will ensure that wastewater water arriving at the plant is treated to the required standard and will improve the water quality in the Lower Liffey Estuary, a key priority for Irish Water since it took responsibility for water and wastewater services in 2014.
Jean Hobbs, Project Manager with Irish Water, said:
“Having adequate wastewater treatment infrastructure is essential to safeguard the environment and to facilitate housing and commercial development. These works will allow the wastewater generated every day in our homes, schools and workplaces to be treated in compliance with the EU and national wastewater treatment regulations and returned safely to Dublin Bay.”
The upgrade works will facilitate the use of an innovative technology, Aerobic Granular Sludge (AGS), which allows for a greater amount of wastewater to be treated to a higher standard within the current plant.
Innovative technology will remove need for new 9km outfall tunnel
Jean Hobbs continued:
“The upgrade project uses innovative technology to deliver a more sustainable, safe, and environmentally sensitive solution for the Ringsend Wastewater Treatment Plant. Irish Water’s experts identified the new AGS technology as the best solution for the Ringsend Wastewater Treatment Plant and we began detailed testing and trials in April 2015. These trials proved hugely successful and confirmed that wastewater treated by AGS technology can be safely discharged at the current outfall location while protecting the nutrient sensitive Lower Liffey Estuary and Dublin Bay.”
Built in 2005, the existing plant is the largest in Ireland. In 2012 planning permission was granted for a substantial upgrade based on technologies available at the time, which included a 9km long sea outfall tunnel.
The higher quality treated wastewater resulting from the upgrade will be suitable for discharge at the current outfall location, in compliance with the Urban Wastewater Treatment Directive, removing the need for the 9km outfall tunnel originally included in the 2012 proposal.
€70 million invested in Ringsend upgrade to date
To date, Irish Water has invested €70 million in upgrading the Ringsend Wastewater Treatment Plant. This includes advance work to prepare the site for the upgrade, upgrades to the odour treatment facilities, trialling and proving of AGS technology and investigative works to inform the project.
In December 2017, Irish Water appointed a contractor to construct a new 400,000 population equivalent extension at the plant (as laid out in the 2012 planning approval). Works on this capacity upgrade are progressing to schedule and it is anticipated that these will be completed in 2020.
With the UK government demanding a 50% reduction in storm overflow spills by 2029, the era of reactive management is over. Speaking in the House of Commons on 21 July 2025, then environment secretary Steve Reed said, “This Government will cut water companies’ sewage pollution in half by the end of the decade.”
ERG, the leading supplier of odour control systems and industrial gas cleaning & thermal systems, has been awarded the coveted King’s Award for Enterprise.
Welsh Water’s new artificial intelligence-driven tool, ORAI, has been shortlisted for three categories at the prestigious British Data Awards 2026 – underscoring the company’s commitment to using cutting-edge technology to deliver better outcome for customers.
Barhale has completed work on two separate Rapid Action Taskforce Spills projects it is carrying out for Severn Trent.
Hear how Scottish Water has completed its £235 million Ayrshire Glasgow Resilience Project - customers across Greater Glasgow, Ayrshire and East Renfrewshire will now benefit from a more secure and resilient water supply.
Hear how United Utilities is accelerating its investment to reduce spills from storm overflows across the Northwest.
Find out more about the remarkable career opportunities on offer at WSP - scroll down to watch the inspirational video.