Clonshaugh has been chosen as the site for a large sewage treatment plant in north Dublin.
The outflow is planned for Portmarnock, near Ireland's Eye.
Three sites had been considered for the 50-acre facility; Annsbrook and Newtowncorduff near Lusk, and Clonshaugh near Dublin Airport.
The issue provoked 10,000 objections from local interests, including the horticultural industry.
Those opposed to the €500m development claim that a number of smaller sites would be preferable.
But Fingal County Council says that one large plant discharging into the Irish Sea is the most sustainable option.
The 23 hectare site is currently farmland and will require 32km of underground piping to transfer treated waste to sea.
The local authority said Clonshaugh was €18m cheaper than alternative sites, and required the shortest amount of underground piping.
Waste will be dispersed 6km off the Portmarnock coastline.