FAQs

Uisce Éireann, in partnership with Cork County Council, is working to end the decades-long practice of discharging raw sewage directly into Cork Lower Harbour with an investment of €144 million in the Cork Lower Harbour Main Drainage Project.
Before the project started the equivalent of 40,000 wheelie bins of raw sewage was discharging untreated into  Cork Lower Harbour through the agglomerations of Ringaskiddy Village; Ringaskiddy - Crosshaven - Carrigaline; Passage Monkstown; Cobh Town.  

We have made substantial progress in the delivery of this essential project

• December 2016 Shanbally Wastewater Treatment Plant was completed 
• October 2018 Network upgrade and successful completion of the connection of Ringaskiddy Village to the Shanbally Wastewater Treatment Plant
• June 2019 Network upgrade and successful completion of the connection of Passage West and Monkstown to the Shanbally Wastewater Treatment Plant. This means that 30,000 of the 40,000 wheelie bins of raw sewage that were discharging daily into Cork Lower Harbour when the project commenced in 2015, are now being treated before safe discharge to the harbour
• May 2019 O'Connor Utilities Limited awarded the contract for the design and construction of the Cobh to Monkstown Estuary Crossing pipelines in
• December 2020 Cobh to Monkstown Estuary Crossing Contract completed
• July 2019 Contract for the design and construction of the Cobh Town networks awarded to a Farrans Construction and Sorensen Civil Engineering Limited Joint Venture.
• Winter 2021 Expected completion date for Cobh Town Networks

The Cobh Networks Contract will collect the wastewater from Cobh Town's homes and businesses by constructing:

• 5 pumping stations
• 3,750m of gravity sewer mains/pipes
• 3,125m of pumped sewer mains/pipes

The wastewater will be transferred for treatment via the Cobh to Monkstown Estuary Crossing to Monkstown pumping station, from where it will be pumped on to Shanbally Wastewater Treatment plant. 

You can view the information sheet on the project which includes a sketch showing pipelines and pumping station works.

Works began in October 2019 and are expected to take approximately 2 years to complete. 

The Cork Lower Harbour Main Drainage Project consists of: 

• A new Wastewater Treatment Plant (WwTP)
• Circa. 15 new pumping stations and the upgrading of 4 existing pumping stations
• Approximately 30km of new sewers
• A drilled crossing under the estuary

The raw sewage* from Cobh, Passage West, Glenbrook, Monkstown, Carrigaline, Ringaskiddy and Shanbally will be collected into new pipes and redirected to a new WwTP plant at Shanbally.

The treated wastewater will then be safely discharged into the estuary via an existing pipeline near Dog Nose Point.

*The amount of raw sewage currently discharged is equivalent to 49,000 people, i.e. 49,000 PE (Population Equivalent).

Please email the project team at corklowerharbour@water.ie to register for update emails on upcoming information events and construction activities.

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• Text COBH to 50015 (Cobh Networks Contract)

Thank you to the local community for your patience and cooperation as we completed this landmark project. To find out more, check out our video.

The estuary crossing phase of the project was completed in December 2020. This epic engineering feat involved drilling two bores at 60m depth under the Lee Estuary using Horizontal Directional Drilling. Then two sewer pipelines were installed in these drilled bores to make this vital connection between Cobh and Monkstown. Once work is complete on the Cobh Networks Contract, wastewater from Cobh will  be pumped, via the estuary crossing, to Monkstown and onto the Shanbally Wastewater Treatment Plant.  Here is will be treated before being discharge safely into the harbour.

You can view the information sheet on the project which includes a sketch showing pipelines and pumping station works.

The Cork Lower Harbour Main Drainage Project consists of: 

• A new Wastewater Treatment Plant (WwTP)
• Circa. 15 new pumping stations and the upgrading of 4 existing pumping stations
• Approximately 30km of new sewers
• A drilled crossing under the estuary

The raw sewage* from Cobh, Passage West, Glenbrook, Monkstown, Carrigaline, Ringaskiddy and Shanbally will be collected into new pipes and redirected to a new WwTP plant at Shanbally.

The treated wastewater will then be safely discharged into the estuary via an existing pipeline near Dog Nose Point.

*The amount of raw sewage currently discharged is equivalent to 49,000 people, i.e. 49,000 PE (Population Equivalent).

The Cork Lower Harbour Main Drainage Project is required to significantly enhance the water quality in Cork Harbour. Currently, wastewater from Cobh, Carrigaline, Passage West/Monkstown and Ringaskiddy is discharged untreated into the Harbour.

The Cork Lower Harbour Main Drainage Project aims to provide enhanced wastewater treatment through the development of a new wastewater treatment plant at Shanbally County Cork. The Project is important in terms of protecting the environment, facilitating economic development and providing for a growing population. The plant will serve the areas of Cobh, Carrigaline, Crosshaven, Passage West/Monkstown (including Glenbrook) and Ringaskiddy (including Shanbally & Coolmore).

In addition to this, the need for a wastewater treatment plant for Cork Lower Harbour is a requirement under both European and National legislation in order to improve health, integrity of the environment and improve water quality in compliance with the European Union's Urban Waste Water Treatment Directive. The Cork Lower Harbour Main Drainage Project will ensure that these water quality standards set down by regulatory bodies will be achieved, which will help Ireland to avoid substantial financial penalties.

The Project will also have a positive impact on the local economy and community as improved water quality will increase the amenity value of the Lower Harbour, and act as a platform for social and economic development.

The Project includes built-in resilience in order for the wastewater infrastructure to be able to accommodate the increase in local population.

We all create wastewater in our everyday lives. At home, we access water with ease; we twist the tap, we flush the toilet, we hit the button on the washing machine and we twist the nozzle on the shower. Industry, hospitals, schools and offices also create wastewater.

Wastewater can contain a wide range of contaminants, some of which can be broken down in the environment easily, while others are not so easily degraded.

Untreated wastewater poses a threat to public health and the environment. Treatment is therefore carried out in order to produce an environmentally safe liquid that is suitable for disposal to our aquatic environment, such as rivers and seas.

Proper wastewater treatment systems are essential for sustaining modern living and contributing to development, as householders, businesses, industries, schools and hospitals all rely on a robust wastewater treatment system to maintain their daily activities.

Untreated raw sewage has been discharging directly in to the lower harbour for decades.  Wastewater is collected from homes and businesses across the lower harbour area and undergoes no treatment before being discharged into the sea. This practices is in breach of national and European legislation and means Ireland is currently in contravention of the European Union Urban Wastewater Directive.

From the 1st of January 2014, Uisce Éireann took over responsibility for water and wastewater services in Ireland in partnership with the Local Authorities.

Uisce Éireann recognises the vital importance of the Cork Lower Harbour Main Drainage Project to Cork and to Ireland. Cork County Council will support Uisce Éireann in the continued development of this Project.

The Environmental Impact Statement (EIS), approved by An Bord Pleanála, concluded that the project will have a positive impact of the environment, marine life, water quality and economy in the Harbour in general by removing the current raw sewage discharges.

Modelling, completed by University College Cork, of the existing untreated discharges and the future treated discharge at 80,000 PE, is included as part of the EIS. The modelling shows a positive impact in reduction of nitrogen levels and faecal coliform pollution. The positive impact extends, not only to the inner Harbour, but also to Lough Mahon, the North Channel of Cobh and the outer Harbour to Roches Point. Specialist Marine Flora and Fauna surveys and analysis also supports this conclusion.

Modern wastewater treatment plants are designed to minimise the risk of odour emissions. There have been extensive engineering advances in the technology employed to run wastewater treatment plants in recent years. Modern plants are covered and have extensive odour, emissions and noise controls in place, and this will be the case with the Shanbally site.

The following measures are being taken:-

• Even though many modern wastewater treatment plants are as little as 50 metres from houses, the perimeter of the Shanbally site is at least 250 metres from the nearest existing house.
• Odour limits at the boundary of the site have been set at 3 odour units on a 98th percentile basis by An Bord Pleanála conditions.

An odour unit is a measurement of the concentration of odour(s) that can be detected. It is measured as 1 ouE, a European Odour Unit. An odour unit of 1 is very weak, and wouldn't be detectable outside the environment in which it was caused. As odour becomes more concentrated, it then gradually becomes more apparent. A good guidance rule of thumb on concentration is (and this is based on laboratory conditions):

• 1 ouE m -3 is the point of detection;
• 5 ouE m-3 is a faint odour; and
• 10 ouE m-3 is a distinct odour

A 98th Percentile is the value 'x' of a year of hourly averaged concentrations means that hourly averaged concentrations will be less than or equal to 'x' (in this case 3 odour units) for 98% of the year.

There are no known health risks to the general population posed by the operation of WwTPs. All gases produced during the treatment processes will be treated on site before venting to the atmosphere.

An appropriately constructed and well operated plant and sewer network should have no adverse impact on the area in which it is located.

The Project Team has liaised with local business groups and restrictions will be placed on Contractors to minimize construction impacts on tourism. In practical terms, no work will be permitted in certain areas during the tourist season. The improvement in the water quality will be a major benefit to all water-contact tourism.

All potential impacts resulting from construction works have been assessed during the preparation of the Environmental Impact Statement (EIS and Natura Impact Statement (NIS)) and suitable management measures will be identified to reduce or eliminate any impacts.

The most noticeable impact during the network contracts will be on traffic as temporary lane closures and road closures will be required in order to safely lay sewers in the road. Uisce Éireann, and its Contractors will liaise with the local area staff of the Cork County Council, the Gardaí, local industry, schools, businesses and local residents to minimize the impacts of the works.

Lands will be reinstated ( i.e. returned to their previous state), and Uisce Éireann will ensure that the Contractors comply with this commitment through liaison with the Local Authority.

Furthermore, Uisce Éireann, and its Contractors, will liaise closely with the community before and during construction to ensure a constant flow of information, and to ensure that local considerations are taken into account, such as in developing the traffic management plan, for example.

If you have any questions or require further information you can contact the project team:

Email: corklowerharbour@water.ie

Cork Lower Harbour Main Drainage Project,
Uisce Éireann,
PO Box 860,
South City Delivery Office,
Cork City.

A new wastewater treatment plant at Shanbally commenced treating wastewater from the Cork Lower Harbour area in December 2016.  Construction of the treatment plant started in August 2015 and in less that 18 months, we went from a greenfield site to an operational wastewater treatment plant, treating the wastewater from over 10,000 homes and businesses across Crosshaven, Carrigaline and Shanbally. 

Since then, we have repaired and extended the sewerage network and connected Ringaskiddy , Passage West and Monkstown to the Shanbally Wastewater Treatment Plant. This means that 30,000 of the 40,000 wheelie bins of raw sewage that were discharging daily into Cork Lower Harbour when the project commenced in 2015, are now being treated before safe discharge to the harbour.

From 2000 to 2009, the Project Team (Mott Mc Donald Pettit), managed by Cork County Council, undertook an Environmental Impact Assessment (EIA) on the Project. The Environmental Impact Assessment looked at any potential environmental impacts of the Project and associated mitigation measures that may be required.

As part of the EIA process an Environmental Impact Statement (EIS) is produced. This stated that the provision for a WwTP at Shanbally will not have significant adverse effects on the environment and would be in accordance with proper planning and development of the area.

The EIS examined nineteen potential sites for wastewater treatment. Nine of these were examined in detail as part of ten options, ranging from one treatment plant (the recommended solution) to four individual treatment plant sites.

In 2009, An Board Pleanála approved the construction of a wastewater treatment plant at Shanbally, Ringaskiddy Co. Cork and the construction of four major pumping stations at West Beach (Cobh), Carrigaloe , Monkstown and Raffeen, together with the modification of Church Road (Carrigaline) pumping station, to result in an overall catchment network of twenty small and five large pumping stations, as well a single outfall off Ringaskiddy which is already in operation.

A site for the new WwTP has been selected at Shanbally (north of West Carrigaline), utilising the existing IDA outfall discharging to the Harbour at Dognose Bank.

The planning application for the WwTP at Shanbally was given permission by An Bord Pleanála in 2009 subject to conditions.

Wastewater treatment plants are described in terms of their designed treatment capacity, which is generally expressed as population equivalent (PE).

This is a measurement of total organic biodegradable load, including industrial, institutional, commercial and domestic organic load, on a wastewater treatment plant, converted to the equivalent number of population equivalent (PE). One person is considered to generate 60g of BOD per day (BOD is the 5 day biochemical oxygen demand); and 1PE is defined as being equivalent to 60g of BOD per day.

In the case of the WwTP at the site in Shanbally, the estimated PE for the plant is 65,000 PE in the first phase. The plant will be a modular design with capability to expand to 80,000PE as population growth demands as per the original Planning Application.