Bitumen spillage forced Cork City water treatment plant to close for 12 hours during summer

An audit by the Environmental Protection Agency revealed that Uisce Éireann became aware that a bitumen-type liquid had entered the raw water sumps at the Cork Harbour and City Water Treatment Plant at Inniscarra, Co Cork on August 28. File picture: Maurice O'Mahony

The treatment plant supplying drinking water to Cork, including parts of Cork City, was shut down for over 12 hours this summer after an accidental spillage of bitumen into tanks containing untreated water, according to a report by the State’s environmental watchdog.

An audit by the Environmental Protection Agency revealed that Uisce Éireann became aware that a bitumen-type liquid had entered the raw water sumps at the Cork Harbour and City Water Treatment Plant at Inniscarra, Co Cork on August 28.

The facility provides drinking water to a population of almost 144,000 in Cork City and the wider Cork Harbour area. Raw water is extracted from the River Lee at Inniscarra Lake and treated at the nearby plant to provide an average daily output of over 64,000 cubic metres.

An investigation established that contractors working on a roof at the facility had spilled a bituminous product which entered the raw water sumps via a roof gully. The EPA said the exact volume of the spilled material is unknown but was less than 20 litres.

However, the roofing contractors did not report the incident to Uisce Éireann. The spillage was only discovered by a separate team of contractors who were working inside the raw water sumps and observed a slick in the water.

The plant was shut down at 8.15pm on August 28. Water treatment operations were only resumed at 10.45am the following day after the raw water sumps were emptied and risk assessments and monitoring of the water quality were conducted.

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The incident resulted in customers in Ballincollig, Dripsey, Coachford and surrounding areas experiencing low pressure or outages due to what Uisce Éireann described at the time as “technical issues".

The EPA said an analysis of samples of both the raw and treated water from the plant over the following five days were all clear.

The audit report called on Uisce Éireann to ensure that all contractors working at the water treatment plant report any incidents promptly. The EPA instructed Uisce Éireann to submit a report detailing all the actions taken and planned with related timescales.

Uisce Éireann said the Lee Road water treatment plant, which provides drinking water supplies to most parts of Cork City, was unaffected by the incident.

A spokesperson for Uisce Éireann said it prioritises public health and once the issue was identified it acted swiftly to investigate the incident and take all necessary steps.

“All tests on the water quality leaving the plant showed the water remained compliant and was safe to drink,” the spokesperson added.