Jennings O’Donovan, in partnership with AECOM, was commissioned by Uisce Éireann to undertake a comprehensive upgrade of the Lettermacaward Water Treatment Plant (WTP) in County Donegal. The project was designed to increase the facility’s capacity to 2,800m³/d and ensure the removal of the supply from the EPA’s Remedial Action List (RAL). This critical infrastructure project provides a sustainable and secure source of high-quality drinking water for the local community by modernizing every stage of the treatment process.
The development featured significant civil engineering works, including the construction of a new concrete gravity dam at Derkmore Lough. This structure raised the lough’s top water level by 1.5 meters, significantly increasing raw water storage. The project also saw the construction of a new treatment building equipped with advanced Dissolved Air Flotation (DAF) and Rapid Gravity Filtration (RGF) units, alongside modern chemical storage and dosing systems.
Further enhancements to the site included the installation of a new sludge treatment process and dedicated storage tanks to improve environmental compliance. The original water treatment building was not abandoned but strategically refurbished and repurposed to house new welfare facilities, while old process equipment was decommissioned. To support the wider distribution network, two new outlying pumping stations were constructed to boost supply to local storage reservoirs.
The project reached a major milestone in September 2024 when the raised water levels successfully overtopped the new concrete dam. With commissioning and process proving in its final stages, the upgraded Lettermacaward WTP is scheduled to fully enter the supply network by the end of March 2025.
