Clonakilty Wastewater Treatment Plant Upgrade




€7 million


Ryan Hanley was appointed Client’s Representative for the Carbery Muskerry Waste Water Treatment Plants Design, Build, Operate & Maintain (DBO&M) project in 2008. The project incorporated the upgrade of Clonakilty waste water treatment plant as well as the DBO&M phases of thirteen wastewater treatment plants located in County Cork. Clonakilty waste water treatment plant was the first in Ireland to use Nereda technology. The Nereda technology is a new treatment process, which reduces the footprint and operation costs of waste water treatment. The successful implementation of the project has provided a modern waste water treatment facility for the Town of Clonakilty in order to meet the needs of the town and its environs to 2030.

The project won the ‘Local Authority Engineering Initiative Award’ at the 2015 Engineers Ireland Excellence Awards.



Clonakilty is the largest town in West Cork, and identified as an Urban Development Node in the North and West Cork Strategic Plan. The plan intends a doubling of Clonakilty’s population by 2021. In addition to the resident population, there is substantial continued pressure for holiday homes, especially in the coastal areas near the town such as Inchydoney (some of which are served by the same wastewater and water network as the town). Substantial areas of land are zoned for residential development in the County Development Plan and in the Clonakilty Town Plan. The town is heavily reliant on tourism, a sector identified in the Strategic and Development Plans as in need of strengthening.

The existing wastewater treatment plant serving the town and its environs was at capacity and considerable constraints and impediments were placed on any proposed developments. The original design population equivalent for the plant was 5,333. The upgrade of the Wastewater Treatment Plant has reduced the potential for pollution, to the benefit of the local environment, and has facilitated planned growth, including the release of zoned land, with a design population equivalent of 20,500.


Project Details

Client: Cork County Council/Irish Water

Location: Cork

Value: €7 million

The Clonakilty plant is Irish Water’s first Waste Water Treatment Plant to use the new Nereda waste water treatment technology. The new technology:

  • Provides a significantly reduced footprint thereby allowing space for future expansion, as well as long term operational benefits. The new plant, which has four times the treatment capacity of the old plant, fits into the existing site.
  • Allows biological removal of biodegradable organic compounds and nutrients in a single reactor, on a reduced footprint and at reduced costs compared with established wastewater technologies.
  • Reduces the volume of sludge produced, and chemicals consumed.
  • Eliminates the excessive unpleasant odours that were emanating from the old plant.
  • Allows effluent discharges from the treatment facility to meet the EPA license requirements, thus improving the quality of the receiving waters for the key summer period.
  • Uses significantly less than any type of similar-sized conventional treatment plant. (Energy savings of between 25-35% have been realised in Nereda plants already operating in mainland Europe and South Africa.)


In addition, during the project:

  • The existing mechanical plant was refurbished.
  • Inlet works were upgraded.
  • The Long Quay Pumping Station was upgraded and additional capacity for storm water storage was provided, which has significantly reduced the frequency of overflow to Clonakilty Bay.