An Bord Pleanála has granted planning permission for an upgrade of Ringsend wastewater treatment plant adjoining Dublin Bay at a cost of more than €400 million.
The plant treats approximately 40 per cent of Ireland’s public wastewater but has been operating at over capacity and not in compliance with national and EU environmental regulations for many years.
The upgrade will ensure wastewater is treated to the required standard and improve water quality in the Lower Liffey Estuary, a key priority for Irish Water since it took responsibility for water and wastewater services in 2014, the utility said in a statement on Friday.
Treated sewage effluent is currently discharged into the bay at an outfall in Poolbeg, 1 km away from the plant. Earlier this year, Irish Water was criticised for failing to notify bay users after a large discharge occurred there due to a storage tank failure.
The upgrade works will deploy innovative technology to remove pollutants using aerobic granular sludge (AGS), which also allows for a greater amount of wastewater to be treated to a higher standard within the current plant.
Irish Water began testing the AGS option in April 2015. "These trials proved hugely successful and confirmed that wastewater treated by AGS technology can be safely discharged at the current outfall location while protecting the nutrient-sensitive Lower Liffey Estuary and Dublin Bay," said Irish Water project manager Jean Hobbs.
Built in 2005, the current plant is the largest in Ireland. Although it was designed to cater for a population equivalent of 1.64 million people, it currently treats wastewater for the equivalent of 1.9 million people serving Greater Dublin and surrounding areas. The upgrade will increase the population equivalent by 400,000.
In 2012, planning permission was granted for a substantial upgrade based on technologies available at the time, which included a 9km-long sea outfall tunnel. But the AGS option means the tunnel is no longer necessary.
To date Irish Water has invested some €100 million in the project, which includes advance work to prepare the site for the upgrade; improvements to the odour treatment facilities, and trialling the AGS technology. The works are expected to be completed in 2020.
