Galway caught well short on sewage plant
Mutton Island wastewater treatment plant will have to be expanded – or a new treatment plant will need to be built – to take the expected increase in sewage generated in Galway in the next decade, city councillors have been told.
Chief Executive of Galway City Council, Brendan McGrath said that Mutton Island had sufficient capacity at the moment to cater for the sewage treatment needs of the city in the short-to-medium term.
However, he said that with the city projected to grow, “there will be a requirement to increase the treatment plant capacity in the medium to long term” of 10-12 years.
Mutton Island treatment plant serves the city and surrounding county areas of Bearna, Parkmore and Oranmore and operates under an Environmental Protection Agency discharge licence.
The current load of wastewater for the plant was circa 103,000-person equivalent for 2020. It can cater for a daily loading of 170,000-person equivalent at peak demand.
The Regional Spatial & Economic Strategy has projected the population growth in Galway including Ardaun to increase by 42,000 by 2041.
Mr McGrath said that based on these figures and allowing for non-domestic growth it is predicted that the future additional potential load to the Mutton Island wastewater treatment plant will be about 50,000-person equivalent by 2041.
“From this we can conclude that in the short to medium term – five to 10 years – Mutton Island can cater for the city’s growth and demand but in the medium to long term – 10 to 20 years – the available treatment capacity of the plant will be significantly reduced,” he said.
Mr McGrath said an assessment to review options for providing more treatment plant capacity was needed. Irish Water has already commenced an investment plan, which “will assess wastewater treatment needs against growth, development, and environmental pressures,” he said.
That study will assess whether to upgrade the existing Mutton Island plant or build a new treatment plant to service the city and surrounding areas of Bearna, Oranmore and Ardaun.
He confirmed Irish Water had allocated funding for the project, and the study will commence in Summer 2022.
It will include an environmental assessment and public consultation, he said.
“In tandem with this, Irish Water and Galway City Council are investigating short term solutions to ensure adequate capacity is available at Mutton Island. These are being pursued through the Galway Drainage Area Plan and other Irish Water Programmes that are currently ongoing,” Mr McGrath said.
Mr McGrath outlined that the City Development Plan anticipates the delivery of 1,000 housing units in the new town of Ardaun on the city’s east side. The future wastewater load from phase one of Ardaun is estimated to be 5,386-person equivalent, increasing to 12,621 for the entire project.
The initial phase “can be accommodated at Mutton Island”, he said, but “considerable wastewater infrastructure will be need to be provided by Irish Water, Galway City Council and the developer in order to service” Ardaun.
This will involve the construction of a new balancing wastewater tank adjacent to the existing Merlin Park pump station and other measures. It will cost €2.2m in total to complete and is currently at feasibility study stage.