Irish Water has submitted planning permission for an €80 million upgrade of the Ringsend wastewater treatment plant as part of an ongoing €400 million investment in the south Dublin plant.
Jean Hobbs, Irish Water project manager for the upgrade, said it had taken "a number of years" to get to this stage.
The plant is “overloaded at the moment,” and is treating around 40 per cent of Ireland’s sewage, mainly from the wider Dublin area.
The plans were submitted to An Bord Pleanála on Wednesday. There will be a seven week public consultation where people can make submissions on the proposal.
The upgrade will increase the capacity of the plant in order to try and keep pace with the growing population of the Dublin region.
The works will allow the plant to meet the capacity of an additional 400,000 people.
Ms Hobbs said the expansion is required to “try and facilitate the future population growth and business growth” in the capital.
“We are quite confident we are putting our best foot forward,” she said.
The utility is to adopt a new treatment known as Aerobic Granular Sludge (AGS) technology, which it has successfully tested and deployed in Co Cork.
A previous plan to build a 9km outfall tunnel to relocate discharge of treated effluent from the Ringsend plant into Dublin Bay will not proceed.
In 2012, An Bord Pleanála granted permission to Dublin City Council to upgrade the plant to increase its capacity based on technologies available at the time and to build the tunnel.
Subject to the new planning application, the upgrade will enable full treatment of wastewater for the equivalent of 2.4 million people and meet foreseeable development needs to at least 2025.
Irish Water hope that after securing planning permission a contractor to carry out the works will be in place next year.
There has been strong local opposition to previous expansion plans at the Ringsend plant and to the neighbouring waste incinerator run by Covanta, which started operating last year.
Damien Cassidy, a local environmentalist living in Ringsend, has long campaigned against the wastewater plant.
“We do not want to be the centre for sewage collection for all of the city and county,” he said.
The result of the plant’s expansion since it opened in 2005 has been to “centralise the collection of Dublin’s sewage into a beautiful scenic area.”
"Generally speaking the stench in the air is a united front that people do not want," he said, adding preserving the natural beauty of the Poolbeg peninsula had become a "lost cause" for the residents of Ringsend and Sandymount.
Ms Hobbs said Irish Water had been in consultation with the public and neighbouring businesses about the planning application. “We held a public consultation in 2016,” and the utility have tried to talk to “as many people as possible” about the proposal, she said.