Update regarding Blackrock Wastewater treatment plant and network

Uisce Éireann are aware of multiple recent media reports and social media posts / queries to Louth County Council in respect to the presence of decaying seaweed along the beach at Blackrock.

Uisce Éireann have consulted with Louth County Council (LCC) Environment Section, and they have advised that complaints have been received on an intermittent basis from early June 2025 at Blackrock and other coastal areas. Investigations subsequently carried out by LCC did not find any evidence of pollution. It was noted during these site visits that seaweed and algae were being washed up on the shore and in some instances the material was decomposing. This is a natural process and Louth County Council cannot remove material from these locations as they are protected areas. Uisce Éireann can therefore confirm that the material observed on the beach is not sewage.

The table below is taken from the 2024 Annual Environmental report for Blackrock wastewater treatment plant and provides details of ambient monitoring locations and details of any designations as sensitive areas.
 

In 2024 and 2025 year to date, the WWTP discharge was and is fully compliant with the ELVs (Emission Licence Values) set in the wastewater discharge licence that is issued by the Environmental Protection Agency (EPA).

The ambient monitoring results do not meet the required EQS (Environmental Quality Standards) at the river monitoring location upstream of the WWTP.

The coastal/transitional ambient monitoring results downstream of the WWTP meet the required EQS. The EQS relate to the Oxygenation and Nutrient Conditions set out in the Surface Water Regulations 2009. This indicates that the discharge from the WWTP does not have an observable negative impact on the Water Framework Directive status.

Uisce Éireann is committed to delivering public drinking water and wastewater services for the people of Blackrock Co. Louth, continuously upgrading and developing critical infrastructure to support sustainable growth and development while enhancing the environment. 

The following works have been completed to improve wastewater infrastructure at Blackrock WWTP and agglomeration:

Q3 2020 - Upgrading of the existing aeration system was undertaken in 2020. The works consisted of the installation of a new Fine Bubble Diffused Aeration System (FBDA) to replace the less efficient surface aeration system.

Q1 2024 - Under the Infiltration programme, network jetting and surveying of Pipelines in the Blackrock network in close proximity of water courses was completed.

Q4 2024 - Upgrades to Cocklehill pumping station were fully completed, the scope of works to Cocklehill PS included:

• Replacement of the existing foul pumps
• Replacement of the existing storm pumps
• Installation of a new motor control centre (MCC) panel
• Installation of new variable speed drives (VSDs) in the MCC panel for the new pumps
• Installation of intelligent pumps controls
• Installation of telemetry
• Installation of high and low-level float switches to provide backup pump control and raise alarms;
• Provision of a new generator connection such that emergency power can be provided.
• Cleaning and jetting of the wet well before it is re-commissioned
• Rectify any defects associated with the existing dry well pipework and fittings;
• Decommissioning of existing temporary pump arrangement
• Site security improvements
• Installation of new WWPS inlet screens
• New pipework and chamber structure to facilitate screen installations
• Screened material handling and provision of washdown facilities
• Removal of screen from Blackrock WWTP

The following environmental mitigation measures were also undertaken:

• Only well-maintained plant and equipment used on site
• Fuel tanks bunded
• Double skin bowsers used
• Tanks and plant positioned on an impermeable base while refuelling
• Emergency procedure established
• Drip trays used when refuelling

Cocklehill pumping station, stormwater overflow (SWO) is not compliant with regulatory storage capacity requirements and options for further improvements to Cocklehill pumping station SWO activations will be considered under next phase of capital improvements as detailed below.

In relation to future development of Blackrock wastewater network, Uisce Éireann have completed the first phase of the Dundalk-Blackrock Drainage Area Plan (DAP). The DAP will be utilised in the development of plans and programmes for SWO improvement works where deemed necessary (subject to funding and national prioritisation).  The next phase of the DAP is to develop a feasibility study report (FSR) regarding the options for the containment of storm water flows in the vicinity of the Cocklehill PS. This will consider storm water storage at Cocklehill and/or storage at other pumping stations and/or within the network.  The FSR will develop the preferred solution based on the most cost-effective option.  Once this preferred option is selected, detailed design and planning will be required before construction could proceed. The preferred option will also have to tie in with other planned network upgrades and therefore at this stage it is very difficult to provide a timeframe other than it would not be any sooner than 2029.

In addition, a project to connect an element of the Blackrock wastewater network to the Dundalk network feeding the Dundalk WWTP (Blackrock Local Network Reinforcement/Load Transfer project) is under assessment and subject to budget approval. Subject to that, it has been scheduled for completion by 2029. The Dundalk WWTP will be upgraded and detailed design is commencing, and this upgrade is being designed with sufficient treatment capacity to accept the full Blackrock load and to facilitate ultimately the de-commissioning of the Blackrock WWTP. Currently the programme for the Dundalk upgrade is 2033 and the full transfer of all the Blackrock load would then be dependent on a number of other network projects being completed. WWTP upgrade projects have typically 5-7 year delivery programmes (once detailed design has commenced) because of the need for modelling studies of the receiving waters, preparation of an EIAR (Environmental Impact Assessment Report), obtaining of planning permission, obtaining of an EPA license all of which has to be completed before construction can begin.