Ringsend Wastewater Treatment Plant Upgrade Project

Uisce Éireann has completed a €550 million upgrade of the Ringsend Wastewater Treatment Plant (WWTP), the largest wastewater treatment project ever undertaken in Ireland in a major milestone for the Greater Dublin Area.

This essential investment ensures the plant can meet the needs of a growing population, comply with EU environmental standards, and safeguard the water quality of the Lower Liffey Estuary and Dublin Bay for decades to come.

About the Ringsend Wastewater Treatment Plant

The Ringsend Wastewater Treatment Plant has been treating Dublin’s wastewater since 1906 and today is the largest WWTP in Ireland, treater approximately 40% of all public wastewater, serving the four Dublin City, Fingal, Dún Laoghaire–Rathdown, South Dublin and parts of Kildare and Meath.

Before this project, Ringsend WWPT was overloaded and not compliant with the Urban Wastewater Treatment Directive (UWWTD) or its EPA Wastewater Discharge Licence, particularly regarding nitrogen and phosphorus removal to protect a nutrientsensitive waterbody.

In 2019, the European Court of Justice ruled that Ireland had failed to meet its obligations under the Directive, increasing the urgency to deliver a long-term solution.

This upgrade directly addresses these challenges by:

• Increasing overall treatment capacity
• Delivering advanced nutrient removal
• Protecting the Lower Liffey Estuary and Dublin Bay
• Supporting sustainable housing and economic development

Construction began in 2018 and was delivered across multiple phases to maintain full treatment operations throughout, despite the plant operating over capacity.  The completed upgrade now provides treatment capacity for 2.4 million PE, enabling Dublin’s wastewater to be treated to the required environmental standards.

Key elements include:

1. Provision of additional secondary treatment capacity with advanced nutrient reduction; (400,000 population equivalent)

    

2. Advanced Nutrient Removal (AGS Technology)

   Installation and retrofit of Aerobic Granular Sludge (AGS) technology across new and existing tanks allows for high performance treatment in a compact footprint.

    

3. Phosphorus Recovery Facility

   A new facility recovers phosphorus, producing struvite, a valuable EU recognised fertiliser. This supports circular economy objectives and is a key step in enabling Ringsend Wastewater Treatment Plant to achieve compliance with the Urban Wastewater Treatment Directive.

    

4. Expanded Sludge Treatment Facilities

   Upgraded infrastructure increases energy generation on site, with 40–50% of the plant’s energy now produced internally.

The Ringsend Upgrade is a central component of the wastewater strategy for the Greater Dublin Area. As the region continues to expand, the Greater Dublin Drainage (GDD) project will provide additional treatment capacity and network resilience.

Together, these investments support:

• Continued housing delivery
• Economic development
• Environmental protection
• A resilient wastewater network for decades to come

• Protects the ecological health of the Lower Liffey Estuary
• Supports climate and circulareconomy objectives
• Enables sustainable growth across the Greater Dublin Area
• Provides long-term resilience in combination with GDD
• Ensures compliance with EU wastewater regulations

With the Ringsend WWTP upgrade now complete, Uisce Éireann will continue to advance the Greater Dublin Drainage project, the next strategic investment required to meet long-term population and economic growth across Ireland’s capital region.