Thousands of seabirds, including puffins, nest each year on Ireland’s Eye, a small uninhabited island off the coast of north County Dublin.

The island, about a kilometre north of Howth, is designated a conservation area in three different ways, according to a Fingal County Council report. “This means that it is of European Importance for nature conservation,” it says.

In November 2019, Irish Water got planning permission to build a new wastewater-treatment plant not far away, at Clonshaugh, near Dublin Airport. If built, it would discharge treated water into the Irish Sea about one kilometre northeast of Ireland’s Eye.

Opponents of the plan decided to fight it. Among their concerns is that treated water would still contain microplastics, which could also absorb other harmful pollutants and potentially damage the abundant marine life in the area, they say.

A spokesperson for Irish Water says that the plan isn’t risky for the fish and shellfish in the sea, or for the protected birds that nest and gather on Ireland’s Eye.

Following a judicial review, the planning permission was quashed in the high court last November. But the issue is due back in court next month when the judge will decide what happens next.

What Is the Plan?

At the moment, a plant in Ringsend treats about 40 percent of the country’s wastewater, says a spokesperson for Irish Water.

It is designed to treat water from 1.64 million people, but is serving 1.94 million. So Irish Water plans to spend €500 million to upgrade Ringsend and increase its capacity so it can treat water from 2.4 million people.

But that won’t be enough capacity for the Dublin region going forward.

The Greater Dublin Drainage Project – as the Clonshaugh plant is officially called – “represents the next major step in the development of the wastewater treatment infrastructure in greater Dublin, recognising its continued growth”, says an Irish Water spokesperson.

The plan is to carry out water treatment for another 500,000 people, including both domestic and non-domestic customers, at the Clonshaugh plant, he says.

“Having adequate wastewater treatment capacity is vital to protect public health, safeguard the environment and facilitate sustainable social and economic growth,” says the spokesperson.

The project is essential for residential and commercial development across north Dublin and south Fingal, he says.

How Clean Is the Water?

Opponents of the plant have a number of serious environmental concerns, says Sabrina Joyce-Kemper, who lives in Portmarnock, near where the pipe would discharge treated water into the sea, and took the court case against the plan.

One is around microplastics. Wastewater treatment would remove some microplastics but not all, and other pollutants can be absorbed into these microplastics.

Joyce-Kemper says that she recognises the need for wastewater treatment, but considers the Irish Water plan to be the cheapest option – not the best one.

The area where the wastewater would be discharged into the sea has been specifically protected forharbour porpoises and seabirds, she says.

The outflow pipe would discharge near the Malahide razor-clam fishery too.

“That whole area is one big shellfish area and a spawning ground for fish,” she says.

By pumping in microplastics, “you are setting up the whole food system for marine mammals and for protected seabirds, to be contaminated from ground zero and to be passed up the food chain”, she says.

She raised concerns about microplastics in her written submission and at the oral hearing for the planning application for the plant. But she says An Bord Pleanála “did not assess microplastics at all”.

(A search of the inspector’s report brings up the word microplastics once and doesn’t address them as a concern.)

The spokesperson for Irish Water says the company is collaborating in research projects on the issue, and that tackling microplastics is best done at source.

“Waste water is not a source of microplastics,” he says. “Rather, the waste water treatment infrastructure … is a pathway for microplastics to the aquatic environment.”

The treatment process removes 80–95 percent of microplastics, he says.

The wastewater will be treated to ensure the EU water-quality standards – as laid down by the EU Water Framework Directive – are preserved, he said. “This will safeguard the quality of the marine environment, beaches and bathing water.”

For another project, Irish Water plans to spend €1.3 billion piping water into the Dublin region from the Shannon basin in Tipperary.

It plans to do this because of a shortage of water in the Dublin region, so why not recycle the wastewater instead? That procedure is common in some other EU countries, including Germany.

That would involve treating the wastewater to a higher spec before it could be used for agriculture, industry or released back into rivers, says the Irish Water spokesperson.

The idea was considered for the Greater Dublin Drainage project, he says.

But “a robust process over a number of years” identified the current plan for a wastewater-treatment plant at Clonshaugh discharging into the Irish Sea “as the optimum solution”, he says.

Washed out to Sea?

The An Bord Pleanála inspector’s report considered the potential for “significant adverse marine water quality impacts” once the plant is up and running, but the inspector concluded that there is no likelihood of that.

The treated water discharge has the potential to affect water quality and shellfish, says the report. But it will not do so because “the diffuser is located in an area where there is high levels of dispersal in the near field … and is designed to enhance dilution.”

The inspector considered a number of potential risks to marine life once the plant is operational, but in each case she said: “these impacts can be discounted from further consideration in terms of marine biodiversity for the purposes of EIA.”

At a regional level, the project will lead to an improvement in marine water quality, because it will relieve the Ringsend plant, says the report.

What will happen once the water is discharged relies on modelling done for the environmental impact assessment, says Joyce-Kemper.

She says that themodelling indicatesthat** **the pipeline discharge is in an area where the tide circulates so the discharged water won’t move out to sea, but will wash up and down the coastline, she says.

“In this particular part of Dublin Bay, the water washes up the coast towards Malahide and Donabate and washes back down around Howth and Ringsend,” she says. “It doesn’t go east to west, it goes north to south.”

She says the EPA should carry out a new, totally independent environmental impact assessment and do its own modelling.

“The essential idea of the EIA [environmental impact assessment] directive is that a development consent cannot be granted until they are absolutely sure that it won’t have an environmental or public health impact,” she says.

A spokesperson for the EPA says that it will carry out an assessment of the plan if and when Irish Water applies for a waste-discharge licence.

Irish Water was granted planning permission in November 2019, and according to the Irish Water website, its next step is to apply for a licence before starting construction of the plant.

But it hasn’t done so yet, says a spokesperson for the EPA.

“The authorisation process provides for the agency to place stringent conditions on the operation of such discharges,” says a spokesperson for the EPA.

A spokesperson for Irish Water didn’t respond before publication to a query as to why it hasn’t applied for the license yet.

Laoise Neylon is a reporter for Dublin Inquirer. You can reach her at

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