WASTEWATER
The Greater Dublin Drainage( GDD)
Project is one of the largest and most critical wastewater infrastructure projects in Ireland’ s history. It will protect public health, safeguard the environment, and support sustainable growth to 2050 and beyond.
By Joanne McIntyre, Valve World
Greater Dublin Drainage Project
This essential national infrastructure project includes the development of a new regional wastewater treatment facility to serve north Dublin and parts of the surrounding counties of Kildare and Meath. The GDD Project was granted planning permission by An Coimisiún Pleanála( Ireland’ s independent, national planning body that decides on planning appeals and major infrastructure projects) in July 2025.
Essential infrastructure
The Greater Dublin Drainage( GDD) project is identified under Project Ireland 2040 and the National Development Plan as essential national infrastructure to support sustainable growth and housing delivery in the Greater Dublin Area. Main construction works is scheduled to begin in late 2026, with construction on track for completion in 2031. Once operational, GDD will provide wastewater treatment capacity for the equivalent of 500,000 people, supporting housing delivery for up to 185,000 homes, while reducing pressure on existing treatment plants and protecting coastal waters in line with national and EU environmental standards. The GDD project solution consists of:
• A regional wastewater treatment facility and sludge hub centre
• An underground orbital sewer and pumping station
• A sewer to divert part of an existing sewer to the new facility
• An outfall pipe to discharge treated water into the Irish Sea
• A regional biosolids storage facility
Operational challenges
Wastewater treatment presents a raft of operational challenges for valves and actuators, including:
• Clogging: Fibrous materials and suspended solids wrap around internal valve parts( e. g.
Visual of regional wastewater treatment facility at Clonshaugh, courtesy of Greater Dublin Drainage.
swing check clappers or stems), preventing proper closure and causing blockages.
• Abrasive wear and erosion: High-velocity grit, sand, and sludge act like sandpaper on internal components, reducing metal thickness and destroying flow control accuracy.
• Chemical and biological corrosion: Aggressive
wastewater components, hydrogen sulphide gas, and treatment chemicals corrode standard metal bodies, seats, and seals.
• Low-pressure leakage in air valves: Sewage air release valves may fail to seal properly at low line pressures after pump shutoffs, resulting in foul odours, environmental spills, and hazardous leaks.
• Cavitation and scaling: Rapid pressure drops create collapsing vapour bubbles that pit valve surfaces, while mineral scaling restricts moving parts and degrades performance.
18 Valve World November 2026 www. valve-world. net