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Grange Wastewater Treatment Plant Upgrade

Wastewater Project

This upgrade forms part of a €16 million investment into four wastewater treatment plants in Sligo, delivering significant improvements to the wastewater infrastructure, serving a future population of 8,300 people.

The upgrade works will increase the treatment capacity of the plant allowing for future economic development and improved water quality in the town and surrounding areas. The works will also ensure that wastewater is treated and discharged in compliance with the Urban Wastewater Treatment Regulations and with the conditions of the Wastewater Discharge Licence (WWDL) issued by the Environmental Protection Agency (EPA).

€16 million


  • Increased treatment capacity of the plant to meet current needs of the town and allow for future growth
  • Improved water quality of nearby coastal areas, protecting bathing areas and the environment from pollution
  • Ensure wastewater is treated and discharged in compliance with EU regulations

What was involved?

  • Increased capacity of the existing wastewater treatment plant from 280 population equivalent (PE) to 900 PE.

  • Constructed new inlet works, a storm water holding tank, a new secondary biological treatment process, final settlement tanks, a new control building and a new sludge thickening facility.

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