Arklow Wastewater Treatment Plant

Uisce Éireann has successfully completed the construction of the €139 million, Arklow Wastewater Treatment plant and has eliminated the discharge of Raw Sewage into the Avoca River.

Arklow was identified by the Environmental Protection Agency (EPA), as an area where wastewater was discharged into the Avoca River without any treatment. This practice of discharging untreated wastewater to the river is no longer acceptable. The European Commission took Ireland to the Court of Justice of the EU for its failure to ensure that urban wastewater in 38 agglomerations across the country is adequately collected and treated to prevent serious risks to human health and the environment.

There were multiple planning delays due to site selection, however, planning was submitted in September 2018 for the construction of the Arklow WwTp with construction commencing in 2021.

Ward and Burke Construction Ltd. completed these works on behalf of Uisce Éireann, 6 months ahead of schedule and on budget.

The Arklow Wastewater Treatment Plant project included the following:

• Demolition and site clearance of the Old Wallboard Factory.
• Architectural Design to produce an art piece along the coast of Arklow.
• Construction of a new wastewater treatment plant (WwTP) to treat 24,000 population equivalents (with the option to expand to 36,000 PE) at the Old Wallboard Factory site located at Ferrybank, Arklow. On the site of the WwTP there are:
  - An Inlet Works Building including a storm water tank.
  - A Sludge Tank Enclosure. An Odour Control Unit (OCU) will be located within the Sludge Tank Enclosure.
  - An Administration Building. 
  - A process building including six secondary treatment tanks.
• Upgrade to the Rock Revetment along the coast.
• Construction of two interceptor sewer pipelines (along North and South Quay) to bring untreated wastewater to the proposed WwTP. Tunnelling works took place using a specialised Tunnel Boring Machine (TBM) to make way for the new sewer pipelines along the North and South Quays, and under the River Avoca.
• Construction of a marine sea outfall pipe to safely discharge the treated wastewater effluent to the Irish Sea. This new pipe was brought by boat from Norway and was installed along the seabed over Summer 2022 using specialised equipment and marine vessels. The long sea outfall pipe comprises of a HDPE pipe with an internal diameter of approximately 630 mm. Six vertical diffusers will emit the effluent approximately 900 metres out to sea at a depth of approximately 10 metres below sea level. Flow through the long sea outfall pipe will be via gravity.
• Storm overflow and storm water storage site at the Alps.
• Underpinning of the 19 Arches bridge and Quay Wall works to accommodate installation of new interceptor sewer.
• Landscaping and associated ancillary works.

• The new wastewater treatment plant (WwTP) will end the practice of discharging untreated wastewater into the Avoca River.
• Cleaner water will enhance Arklow’s amenity value and act as a platform for social and economic development.
• The project includes the capacity for future growth in the area, new connections for housing and development can now be accepted.
• The wastewater treatment plant will bring benefits in terms of health and integrity of the environment.
• Improve the water quality for recreational swimming, surfers, fishing, boating and sightseeing. 
   

Who can I contact if I want to find out more about this project?

Members of the public are welcome to contact the Project Team if they have any questions on the Arklow Wastewater Treatment Plant Project and can do so in the following ways:

Email: Arklowtp@water.ie  

Web: www.water.ie/arklow

Uisce Éireann would like to thank the local community for their patience and cooperation whilst we delivered this essential project.

The Arklow Wastewater Treatment Plant has been fully operational and treating all incoming flows since Q4 of 2024. It has also garnered huge interest at home and abroad due to its visually appealing buildings, recently winning the prestigious Downes Medal, The Architectural Association of Ireland’s highest honour. This award is not awarded every year which is a testament to the structure itself. Clancy Moore Architects on behalf of Uisce Eireann.

Tunnelling works took place using a specialised Tunnel Boring Machine (TBM) to make way for the new sewer pipelines along the North and South Quays, and under the River Avoca. This construction method minimised the impact on the local community.

Check out some images of the Tunnel Boring Machine as it was launched into the newly constructed shaft at the Ferrybank Roundabout:

Long Sea Outfall:

The long sea outfall pipe safely discharges the treated wastewater to the Irish Sea now that the new wastewater treatment plant is operational. This new pipe was brought by boat from Norway and was installed along the seabed over Summer 2022 using specialised equipment and marine vessels.

The long sea outfall pipe comprises of a HDPE pipe with an internal diameter of approximately 630 mm. Six vertical diffusers emit the effluent approximately 900 metres out to sea at a depth of approximately 10 metres below sea level. Flow through the long sea outfall pipe is via gravity.

Check out some images of the arrival of the outfall pipe from Norway along with the specialise dredger which helped install the outfall pipe at sea: