Discharge of inadequately treated waste water from Ringsend into the Lower Liffey Estuary

Date released: Feb 26 2019

On 25 February 2019, Irish Water informed the EPA of the release of waste water sludge from Ringsend waste water treatment plant into the Lower Liffey Estuary.  The release commenced on the morning of Saturday 23rd February.

The EPA is investigating this incident and inspectors are carrying out a site inspection to determine the cause of the incident and to monitor the discharge.  Our priority is to ensure that Irish Water completes the corrective actions needed to bring the discharge under control and to protect the Lower Liffey Estuary. 

Update 28 February 2019


Irish Water informed the EPA on Monday 25th February about a breakdown within a section of Ringsend waste water treatment plant which occurred on the morning of Saturday 23rd February. The breakdown resulted in the spillage of waste water from the treatment process into the treated waste water being discharged into the Lower Liffey Estuary at Poolbeg. The section of the plant where the breakdown occurred was shut down by 10 a.m. on Saturday and the spillage ceased. This section is still shut down and repairs are being carried out, which are expected to take approximately one month. The shutdown of this section is causing a 5% to 8% reduction in the treatment capacity of the already overloaded plant.


EPA inspectors conducted a site inspection on Tuesday 26th February and found that inadequately treated waste water is still being discharged into the Estuary due to the fact that the plant is operating above its’ design capacity. The inspectors took samples of the discharge, which are now being analysed in our laboratory, and we expect to have the results available in the coming days.


Our investigation, which is still ongoing, found that there are significant variations over time in the waste water load collected in Dublin’s sewers and entering the plant for treatment. Last weekend the total amount of solid matter within the waste water entering the plant was approximately twice the typical amount. The plant was unable to treat this adequately and it is likely that this was the cause of the visible plume extending from the discharge point.


The EPA has repeatedly highlighted in its annual reports that Ringsend treatment plant is failing to meet national and European Union treatment standards. It is failing to meet these standards, and failing to comply with the requirements of its waste water discharge licence (reference number D0034-01) because the plant is not big enough to adequately treat all of the waste water that it receives. This means that the waste water discharged back into the environment is breaching, and will continue to breach, the quality standards until upgrade works are complete. The plant normally has a capacity to treat waste water from a population equivalent of 1.64 million, but this is now temporarily reduced by 5% to 8% following the breakdown last weekend. The load entering the plant is from a population equivalent of approximately 2.2 million. Additional treatment capacity of 400,000 population equivalent is under construction, with a completion date of 2020, and further improvements to bring the treatment capacity up to 2.4 million will be completed by 2023.


The EPA is continuing its investigation into this matter and will continue sampling and monitoring this week. Our priority is to ensure that Irish Water completes the corrective actions needed to protect the receiving environment and public health.


Additional sampling on bathing water quality in the area is being carried out by DCC. Details of bathing water quality can be found at the following link: http://www.dublincity.ie/bathingwater
You can find details about the Ringsend waste water treatment plant on our website here.