An EPA inspection of the Ennistymon Water Treatment Plant identified poor management and an absence of operational control of the sludge treatment process.
The audit took place just one week after a reports of a major fish kill and discolouration downstream at the Ballymacraven river.
The Environmental Protection Agency is the supervisory authority over Uisce Éireann and its role in the provision of public drinking water supplies.
The EPA was initially contacted by Inland Fisheries Ireland on May 3rd following reports of a discolouration and subsequent fish kill in the Ballymacraven River downstream from the Ennistymon Water Treatment Plant.
The announced inspection took place just one week later on May 10th and focused on the treatment and management of the sludge being generated on site and the subsequent supernatant discharge to the river.
The supernatant is the liquid by-product of the residual waste which emerges following the treatment process.
The sludge treatment process on site at the Ennistymon plant consists of two picket fence thickeners and dewatering units.
On the day of the audit, it was noted that neither of the PFTs were in operation due to mechanical failures.
The sludge is subsequently directed to a holding tank, however Clare County Council advised that the agitator within the tank was not working.
Neither Uisce Eireann or Clare County Council could confirm the duration of this malfunction.
The audit found that there was poor management and control of the sludge treatment process at the site, citing the lack of alarms to alert plant operators of any malfunction during the treatment stage.
The report also found the frequency of removal of sludge from the site to be insufficient.
Clare County Council subsequently provided records to show the collection of sludge from the plant has since increased to 145 tonnes four times per week .
Inspectors further noted that the measures in place to prevent inadequately treated water entering the distribution network were unsuitable.
The gravity filters and chlorination system were also inspected, and it was found the filters were found not designed or managed in line with EPA guidance.
The Ennistymon Water Treatment Plant has been on the EPA’s remedial action list since 2015, and the latest report found the facility to be operating well above design capacity , producing 320 cubic metres of water per hour, 60% above the intended limit.
The EPA outlined ten key recommendations to be implemented by Uisce Eireann without delay to ensure a clean and wholesome supply of drinking water.
Uisce Eireann has advised the EPA subsequent to the audit that sludge treatment works will be completed by the second quarter of 2025 and will include the installation of a new sludge balancing tank , PFTs , sludge holding tanks along with electrical and instrumentation works.
Uisce Eireann stated that as part of ongoing works to upgrade the Ennistymon Plant, the current sludge treatment facility will be demolished in the next 12 months.
In a statement to Clare FM, Uisce Eireann says its undertaken changes to the management of Ennistymon Wastewater Treatment Plant as a precautionary measure.
