Facts & Figures

 ClientIrish Water
 LocationDublin - Ringsend, Ireland
 Operation Start2017
 Project TypeRetrofit
 Process ConfigurationPre-treatment + Primary settler + Nereda
 Nereda Design Capacity:
  • Dry Weather Flow600 MLD
  • Peak Flow50,000 m3/h
  • PE2,400,000 PE (PE = 60 gBOD/d)


Ringsend is an inner suburb of the city of Dublin, Ireland. It is located on the south bank of the River Liffey and east of the River Dodder, about two kilometers east of the city center.


The existing Ringsend WWTP was commissioned in 2003 and had a design capacity of 1.64 million population equivalent, capable of handling a flow of 11.3 m³/second. But prior to its upgrade it was operating over that capacity, at 1.9 million p.e. The principal effluent requirements were based on only Carbon (BOD and SS) removal. The existing WWTP consisted of 24 SBR tanks, stacked in a two-layer deck of 12 SBR tanks per deck. Each tank had a volume of 13,500 m³.


To address the overloading of the facility and related bottlenecks in the operation – and to introduce nutrient removal to meet the level of treatment required by the European-based Urban Wastewater Treatment Directive – a major upgrade of the plant at the existing site was proposed. Irish Water selected Nereda technology for extending and upgrading the existing infrastructure and bringing the Ringsend WWTP capacity up to 2.4 million p.e. (144,000 kg BOD/d) and 600,000 m³/d, with a peak flow rate of 13.8 m³/sec.

The major works of the project includes retrofitting existing SBR-cells to Nereda process and constructing additional new Nereda reactors on a remaining undeveloped plot on the existing site.


Image: Operacional Nereda Reactor


One of the characteristics of the project is its scale, with 40% of all Irish wastewater treated in this facility. The project is a complex one, as the treatment plant must remain operational throughout the retrofit, and there is only a small footprint available for extension. In addition, the current sludge handling and treatment facilities need to be adjusted to accommodate the increased sludge production.

The retrofit and plant extension will stepwise increase the treatment capacity and treated effluent quality without compromising the existing treatment performance. In 2017, the first SBR-cell was retrofit to become a Nereda reactor, and this has demonstrated good performance. Construction of the 400,000 p.e. new Nereda reactors started in early 2018 and once in operation, will enable an increased speed of retrofitting the remaining SBR-cells. Overall completion of the project is estimated to be in 2027.

Royal HaskoningDHV is working on the project with its Irish partners, TJ O’Connor & Associates and J. B. Barry and Partners. Celtic Anglian Water is the operating and maintaining the Ringsend WWTP.


View more information on the Dublin, Ringsend WWTP Process Proving Step 1 and 2 here.

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The local benefits of the project

Nereda logo small Greater treatment capacity
Nereda logo small Future proof compliance
Nereda logo small Retrofit solution
Nereda logo small Green and sustainable
Nereda logo small  Small physical footprint