Killarney national park hit by 75 Olympic pools of wastewater in just three months

By Alastair Tibbs, The Kerryman

A recent report on Killarney’s wastewater treatment plant has found that large volumes of storm water were emptied into the national park last year.

A component of the storm water is sewage that has been screened, potentially up to 20pc, due to Killarney’s combined sewage and stormwater network.

An inspection carried out by the EPA highlighted that a volume the equivalent of 75 Olympic swimming pools was discharged into a stream flowing into Lough Léin.

The impact of Killarney’s wastewater treatment plant on Kerry’s national park was officially recognised by the EPA in July when the agency placed the plant on its priority list.

Killarney’s sewerage system has long been a source of concern for local groups and environmentalists, with Lough Léin being designated as having ‘moderate’ ecological status.

An EPA visit to the treatment plant has now found that 187,191 cubic metres of discharge was released from an overflow point over the course of 90 days last year.

This equates to over three-quarters of an Olympic swimming pool a day released into the stream adjacent to the plant, the Follies Stream.

Due to Killarney having a partially combined sewer network - an older style of drainage system which collects both domestic and business wastewater, with surface water run-off – any overflow at the point discharging into the Folly Steam could consist of up to 20pc sewage that has been screened, according Killarney’s Area Drainage Plan Stage 4 Report.

The entire Killarney system has eight storm water overflows (SWOs) spread across the area around the town and the monitoring of these values appears to vary.

Locations of SWOs according to Killarney’s Annual Environmental Report

According to the EPA’s report, volumes of discharge at treatment plant’s overflow point were ‘unknown’ in 2024, despite the existence of a monitor.

Another two points were reported to be monitored but during inspection this year, it was stated that they were not monitored.

The naming of another varied, according to inspectors, and the location of two were ‘to be confirmed’, despite their coordinates appearing in annual environmental reports.

The inspector was told that there were plans to install event monitors on all SWOs.

Uisce Éireann responded that storm water overflows play an important role in protecting homes, businesses and public spaces from wastewater flooding during severe weather events.

They said they recognise the need to continually improve wastewater infrastructure and have commenced Stage 1 of a Strategic Assessment for Killarney Wastewater Treatment Plant, which will examine the area’s long-term wastewater needs, assess potential infrastructure solutions and identify opportunities to enhance environmental performance and compliance with updated legislative requirements.

The Strategic Assessment is expected to continue through 2026 and into 2027, after which the project would progress to Stage 2, the Preliminary Business Case stage, subject to governance approvals and funding.

“Killarney Wastewater Treatment Plant is a complex piece of wastewater infrastructure, and improvement works must be carefully planned to ensure the safe and continuous operation of this critical asset,” said the water utility.

“Uisce Éireann is taking action to address the issues with Killarney Wastewater Treatment Plant and works closely with the relevant regulatory and public health bodies in relation to its operations and any issues that arise. Protecting public health, safety, and the environment remains our priority.”

Kerry County Council previously zoned land in January for an open-air wastewater treatment system located inside Killarney National Park.

The zoning of land for an Integrated Constructed Wetland (ICW) was passed by Killarney’s councillors at the start of this year as part of the revised County Development Plan.

Killarney Wastewater Treatment Plant and the proposed ‘wetland’ on the previously dug circle

An ICW typically consists of series of artificial ponds that are filled with plants and natural organisms that breakdown and remove pollutants.

The ICW land is next to Killarney wastewater treatment plant and in the plan, the council say they support Uisce Éireann in developing solutions to the impacts of wastewater discharges during summer droughts.

Specially, they support ‘controlled and monitored discharge of storm water overflows to the nearby Integrated Constructed Wetland, subject to the outcome of all required environmental assessments and in accordance with any required permits/consents/licences’.

In 2019, such a wetland was installed at Lixnaw and, according to Uisce Éireann is currently experiencing “several challenges that affect performance and impact the local environment”.

These include “odour issues that are a concern for the community as well as water quality and system efficiency during certain weather and tidal conditions”.

This article was updated at 4pm on September 19 to include comment from Uisce Eireann.