County Dublin residents have begun a legal challenge against permission for a €500m wastewater treatment plant at Clonshaugh.
The High Court application is being made in the name of Sabrina Kemper Joyce one of the Portmarnock objectors who labelled the development a "monster sewage plant".
Local residents said after the grant of permission that An Bord Pleanála had failed to take proper account of the EU's Birds and Habitats Directives.
The planned outfall is at sea around one kilometre from Ireland's Eye which is a Special Area of Protection (SPA) - one of nine SPAs on the Dublin coast.
Irish Water had sought the development to cater for future population growth and because the existing Ringsend plant is operating at over-capacity which has led to discharges of partially treated sewage into Dublin Bay.
The plan involves 13km of underground orbital sewer from Blanchardstown to the Clonshaugh plant and then a 12km outfall pipeline to bring the treated wastewater to Baldoyle and out to sea.
However there were 13,000 objections largely due to concerns over the effects on Dublin Bay.
Papers have been lodged to the High Court and an application for Judicial Review of An Bord Pleanála's decision is listed for next Thursday.