Limerick Wastewater Treatment Plant Upgrade and Regional Bioresource Centre
Uisce Éireann is progressing plans to upgrade the Limerick Wastewater Treatment Plant
Uisce Éireann is progressing plans to upgrade the Limerick Wastewater Treatment Plant
Project Background
Limerick Wastewater Treatment Plant has been providing service to the area since the early 2000s. Biosolids are the bioresource output from the process. Biosolids are the bioresource output from the process. Biogas is the other output. Information is in latest slides attached. The existing plant was last upgraded in 2017 and currently already treats sludge produced at the plant itself and imports from smaller plants in Limerick, Clare and Tipperary.
Uisce Éireann has identified that the Limerick Wastewater Treatment Plant is currently reaching capacity and an upgrade is required to ensure continued environmental compliance, and to support both the existing and future growth and development of Limerick City into the future.
The continuation of appropriate wastewater treatment will be vital to protect both human health and the local environment, as population grows and industry continues to expand in Limerick City.
Limerick Wastewater Treatment Plant has also been selected as the preferred location in the Southern Region for the development of a Regional Bioresource Centre, accepting sludge imports from smaller plants in Counties Limerick, Clare and Tipperary. This forms part of the National Wastewater Sludge Management Plan which aims to deliver a sustainable and standardised approach for wastewater sludge management.
About the project
Limerick Wastewater Treatment Plant upgrade project and Regional Bioresource Centre is cited as a Strategic Infrastructure Development under the Planning and Development Act (2000). A Strategic Infrastructure Development can generally be described as a development which is of strategic economic or social importance to the state or a region. Strategic Infrastructure Development applications are applications for planning permission directly to An Coimisiún Pleanála (previously known as An Bord Pleánala).
The Strategic Infrastructure Development application will be accompanied by an Environmental Impact Assessment Report. The application will be submitted with the relevant application documents.
Why is the project needed?
The wastewater treatment plant has a current capacity to serve approximately 130,000 population equivalent (PE) in Limerick City and surrounding areas. PE is the amount of biodegradable organic matter in wastewater that is equivalent to what one person would produce in a day. In order to support projected growth in the region and meet future demands of Limerick City and surrounding areas, the treatment capacity of the plant needs to be significantly increased to serve a future projected population equivalent (PE) of 285,000 over 10 years with provision for expansion to 325,000 PE. This essential project will also ensure compliance with environmental regulations and protect the Shannon, a designated Special Area of Conservation.
The Environmental Protection Agency defines PE as a measure of the organic biodegradable load, which is calculated based on the maximum average weekly load entering the treatment plant during a year (excluding unusual situations such as those due to heavy rain).
Figure 1-2: Limerick wastewater treatment plant
Proposed upgrades to the wastewater treatment plant include the following:
The Wastewater Treatment Plant capacity upgrade will caterfor 10-year growth projections, extending the existing wastewater treatment plant from 130,000PE to 285,000 PE. Key elements of this upgrade include:
- Construction of a new 157,000 PE inlet works and Aerobic granular sludge (AGS) process stream.
- Upgrade to the existing foul water pumps at Corcanree Main Lift Pumping Station to increase pumping capacity to the wastewater treatment plant.
- Diversion of a rising main from Corcanree Main Lift Pumping Station to the new process stream.
- Retaining existing Mungret pumping arrangement; and
- Retaining existing 1.1km outfall pipe to the Shannon Estuary
The proposed Regional Bioresource Centre will be designed to treat sludge including sludges from other, smaller wastewater treatment plants in County Limerick to the required Code of Good Practice standard for reuse of Biosolids in Agriculture, in alignment with the National WastewaterSludge Management Plan (NWSMP). Works requirements include:
- New dewatered sludge cake reception facility.
- New mechanical thickening system.
- New Thermal Hydrolysis Process (THP) with capacity of50 TDS/day.
- Refurbishment of existing digester feed tanks as pre-THPdewatering feed tanks.
- Upgrade mixing system and transfer pumps
- New odour control system.
- New dewatering and storage installations
- New/additional AD tank (optional).
- Biogas storage bell (optional).
- New/ additional Combined Heat and Power Engine(CHP).
- New digested sludge tank and dewatering system.
- New Class A biosolid storage silo
- New centrate return pumping station.
- Upgraded wash water system with added UV treatment.
The proposed stormwater storage tank is a large piece of infrastructure that must cater for the long-term 25-year expansion. Total storage volume for the long term projected 325,000 PE is calculated to be c. 20,000m3 in accordance with Urban Wastewater Treatment Directive (UWWTD) stormwater storage requirements. Works requirements include:
- Development of a hydraulic model to determine spill rates and final tank sizing.
- Acquisition of lands adjacent to Corcanree Main Lift Pumping Station
- Construction of a new 12,500m3 stormwater storage tank and associated pipework.
What are the benefits of this project?
- Modernise and enhance the Limerick Wastewater Treatment Plant to meet current and future needs.
- Safeguard public health and protect the integrity of the local environment.
- Protect and improve water quality and support the unique conservation habitats of the Shannon Estuary.
- Maintain compliance with all national and EU environmental standards into the future.
- Improve efficiency and reduce operating costs for sludge treatment.
- Transform wastewater sludge into a valuable, reusable bioresource.
- Generate renewable energy on-site to help power the facility and reduce its carbon footprint.
What's happening now
Uisce Éireann engaged with the local community and stakeholders regarding the proposed project through a non-statutory consultation process before the formal planning application was submitted to An Coimisiún Pleanála (previously known as An Bord Pleánala).
This consultation has now closed. All feedback received in response to this consultation has been recorded and has been considered by the project team. A summary of feedback received during this consultation process has been included in the Environmental Impact Assessment Report which was submitted with the planning application to An Coimisiún Pleanála.
Further details on the project are available here.