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Proposed Solution

In April 2019, An Bord Pleanála granted permission for the works required to facilitate the use of Aerobic Granular Sludge (AGS) technology, to omit the previously permitted long sea outfall tunnel and to upgrade the sludge treatment facilities at Ringsend, Dublin 4, and to provide for a Regional Biosolids Storage Facility in Newtown, Dublin 11. This further upgrade of the Ringsend Wastewater Treatment Plant will enable future population growth and ensure the plant operates to the highest possible environmental standards.  For further details on this planning application please visit our Environment and Planning section.

We are proposing an alternative approach to this project which involves the use of the Aerobic Granular Sludge (AGS) technology treatment process and the exclusion of the originally planned 9km undersea tunnel.

AGS technology is an advanced nutrient removal technology that is a further development of the activated sludge process. This treatment process will consistently produce high-quality treated wastewater which can be safely discharged into Dublin Bay. We have conducted detailed testing and trials of the technology since April 2015 to treat the wastewater being received at the Ringsend plant. These trials have proved successful; confirming that wastewater treated by AGS technology can be safely discharged to the Lower Liffey Estuary and Dublin Bay.


The proposed Ringsend WwTP Upgrade Project includes as follows

  • Additional secondary treatment capacity as approved by An Bord Pleanála in 2012.
  • Proposed works to facilitate the use of AGS technology in the existing secondary treatment tanks, increasing the capacity to 2.4 million Population Equivalent (PE).
  • Proposed exclusion of the previously permitted 9km long undersea outfall tunnel.
  • Proposed expansion of the plant's sludge treatment facilities to match the overall increase in wastewater treatment capacity.
  • Proposed provision of a new phosphorous recovery process.
  • Proposed provision of additional odour control facilities.
  • Proposed increase in the flow through the plant by approx. 20% thereby increasing the amount of wastewater that can be treated and reducing the level of storm overflows which occur during heavy rainfall events.

In particular, it should be noted that:

  • No increase in capacity over that approved in 2012 is being proposed.
  • The revised project will meet the same stringent odour control standards as set out by An Bord Pleanála in 2012.
  • From an operational and visual perspective, the revised project is not expected to result in any significant change on the site of the plant from the project approved in 2012. The main change will occur outside the site due to the proposed exclusion of the 9km long undersea tunnel.

By the end of 2018, Uisce Éireann had invested over €100 million in upgrading the Ringsend Wastewater Treatment Plant. This includes surveys, design and initial works on the new 400,000 population equivalent upgrade as well as advance work to prepare the site for the upgrade, upgrades to the odour treatment facilities and trialling and proving of AGS technology.   

In December 2017, Uisce Éireann 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. 

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