Portrane earmarked for €140m sewerage scheme

A new regional sewage plant in north Co Dublin, with the capacity to serve almost one million people, has been recommended by a major drainage study.

Almost one-third of the initial funding will be spent on the extension of the controversial Ringsend wastewater treatment works. The €300 million state-of-the-art plant opened in July 2003 and has caused persistent odour problems in the southeast of the city since.

The new plant, which would be almost the same size as the current Ringsend works, is likely to be located on the site of an existing sewage works in Portrane, presently serving a local community of a little more than 10,000.

The plant will cost an estimated €140 million to build, and must be constructed in conjunction with a new "orbital" sewer costing €218 million and serving west Dublin and east Meath, if it is to address the capacity problems at Ringsend.

The proposals are part of a new €2.6 billion programme recommended by the Greater Dublin Strategic Drainage Study to meet the sewerage and drainage needs of the greater Dublin area until 2031.

A critical element of the programme is the "immediate extension" of the Ringsend plant at an estimated cost of €50 million and an upgrade of the sewerage systems in Dublin city and the greater region at a cost of over €700 million.

The drainage study, which cost €10 million and involved intensive analysis over five years, covers the needs of Dublin city, Fingal, south Co Dublin and Dún Laoghaire-Rathdown, along with parts of Meath, Kildare and Wicklow.

It recommends an "up-front expenditure" of €1.56 billion to deal with critical capacity problems in the drainage system, and to overhaul decaying sewers within the next six to eight years.

The study states that a number of sewage systems, some dating back more than a century, are "completely overwhelmed" by the population growth, cause "frequent and widespread flooding", result in overflowing sewers and need to be completely overhauled.

Dublin City Council admitted earlier this year that the Ringsend plant had capacity problems and it begins a new programme of work to eliminate the smell this autumn.

The drainage study found that the plant "is at capacity" and would be unlikely to meet the statutory environmental standards for nitrogen discharges into Dublin Bay, unless expanded as soon as the planning process allows. However, it said the expansion would only meet short-term needs and, because of the lack of development land at Ringsend, a new plant outside the city would ultimately have to be built.

The study recommends the development of a new capacity treatment plant at Portrane. The present sewage facility serves the communities of Donabate and Portrane.

The redeveloped plant could process waste equivalent to a population of 850,000-880,000 and would serve the areas of Blanchardstown, Mulhuddart, Lucan and Clondalkin in west Dublin; east Meath; and, eventually, Leixlip in Kildare, through a new 22km orbital sewer.

The plant will also take some waste currently processed at Swords/Malahide as well as Ringsend to reduce "overloading" at those facilities.

The study earmarks Portrane as the preferred site for the new plant, which must first go through the Fingal County Council planning process. The report predicts a seven-13-year timetable for the major infrastructural project.