SLIGO MAIN DRAINAGE WASTEWATER TREATMENT PLANT
Official opening 25th May 2009
Design Build Operate Contract (DBO)
Protecting Our Natural Habitats
Sligeach - The Place of the Shells
Benefits of Sligo Wastewater Treatment Facility
Programme of Events
Introduction by Pat Doyle, Project Engineer
Address by Cathaoirleach Councillor Jude Devins
Address by Mayor Councillor Veronica Cawley
Address by Mark Driver Project Director Anglian Water International
Address by County Manager Hubert Kearns
Address and Official opening by Minister Michael Finneran T.D.
Introductions and Forewords
This state of the art facility will be of enormous benefit to Sligo and its environs and will serve the residential and commercial needs of a wide catchment area, including Cummeen, Carraroe, Ballincar, Teesan/ Lisnalurg and Rosses Point.
The wider significance of this facility is in the context of Sligo’s status as the key centre of economic growth in the northwest. Sligo Borough Council and Sligo County Council have invested extensively in providing wastewater infrastructure to meet existing and future demands, and the delivery of this plant is a landmark achievement which reflects great credit on the project team. The new treatment works has a capacity to treat waste water for a combined domestic and commercial population equivalent of 50,000, with a capacity for future expansion to 80,000.
This brochure sets out the technical detail of the new plant, and places this project in the wider context of our ongoing commitment to our environment.
Councillor Veronica Cawley
Mayor
The planning and delivery of Sligo Waste Water Treatment Plant is one of the most significant projects undertaken by Sligo Local Authorities in recent years. A facility of this importance required a huge commitment from many people, and the Elected Members and Staff of Sligo Borough Council and Sligo County Council, together with the Project Team, can take great pride in seeing this project come to fruition.
The opening of the new treatment plant will enable Sligo Local Authorities to fulfil its obligations under EU Directives, and will have tangible benefits in terms of local business and tourism. In the last ten years Sligo County Council has constructed 25 new treatment plants and laid over 180KM of pipelines. Value for Money is a key factor in rolling out our Waste Water Capital Programme, and elements of the scheme were delivered in ‘bundles’ to ensure the benefits of economies of scale.
Visitors to the site cannot fail to be impressed with the scale and quality of the Plant, a testament to the professionalism of the Project Team.
Councillor Jude Devins
Cathaoirleach
The opening of Sligo Wastewater Treatment Plant is a major development in terms of our wastewater infrastructure. Over the last five years Sligo County Council has overseen the investment of €110 million in our Wastewater Capital Programme.
The new facility will enhance our environment, safeguard Sligo Bay for swimming, fishing and other recreational activities, as well as protecting local wildlife and their habitats. Our ability to promote this region for future development is also significantly improved with the delivery of this facility.
In recent years Sligo County Council has also improved the supply of high quality drinking water to consumers in Sligo and its environs, and we hope to complete our current programme next year with the construction of a new treatment system at Kilsellagh.
I wish to acknowledge the support of the Minister and his Staff at the Department for their continued support during this project and other elements of our capital programme. I also want to commend the members of the Project Team who have been involved in the design and construction of this facility, they can be proud of their achievement.
Hubert Kearns
County Manager
Local Authorities are facing enormous challenges in delivering and maintaining water and wastewater infrastructure and services. Sligo County Council worked very hard with the various members of the project team to ensure this landmark project was delivered on time and within budget.
The scheme will be of major benefit to this Authority in terms of helping us meet our objective of managing and maintaining the other wastewater treatment facilities in the county. The new plant is designed and constructed to the highest international standards, and is a fine example of what can be achieved by Local Authorities in the planning and provision of major infrastructural projects.
I feel the general public have a genuine interest in the operation and maintenance of schemes of this nature. From an educational perspective, I welcome the opportunity to invite schools or community groups to visit the plant, as I believe it represents an excellent model of project management and is a credit to the elected members, staff and project team.
Tom Kilfeather
Director of Services
Overview
Sligo County Council’s new wastewater Treatment facility will mean the elimination of untreated discharges into Sligo Bay and will enable Sligo Local Authorities to fulfil its obligations under EU Directives. The Project is being funded under the National Development Plan through the office of the Minister for Environment, Heritage and Local Government.
The provision of the plant will accommodate demand from tourism, housing, commercial, industrial and recreational developments in the capital City of the North West Region, together with the provision of sludge reception facility for the treatment of all sewage sludge within the county.
Quality Environment
The scheme will ensure the protection of a quality environment in Sligo Bay and will clear the way for the integration of sewerage facilities from the surrounding areas of Cummeen, Carraroe, Ballincar, Teesan/ Lisnalurg, Rosses Point, Hazelwood, Ballinode and all areas designated for development in the Sligo & Environs Development Plan.
The new plant will provide treatment to the highest standard including full secondary treatment supplemented by phosphorous removal and by disinfection using ultra-violet lamps. Sligo has been designated as a sludge hub centre and will therefore include a sludge acceptance facility and sludge treatment centre for sludges generated in County Sligo.
The treatment works will have a capacity to treat wastewater for a combined domestic and commercial population equivalent of 50,000 and it has to be capable of being expanded to 80,000 at a future date.
Story of the Scheme
The plant is constructed in a bunded area of Sligo estuary, which was developed during dredging works in Sligo harbour in the 1980’s. Over the past 25 years, work has been progressing on upgrading and refurbishing the old drainage system and providing new trunk sewers to open up additional land for development.
Jennings O’Donovan & Partners were appointed as designers for all works associated with the development of the sewerage infrastructure in Sligo.
An Environmental Impact Statement was prepared for the treatment plant as is required under Irish Law for all treatment facilities greater than 10,000 population equivalent. Network modelling and a Hydroworks model of the sewer systems has been carried out, and a water services pricing policy report was prepared in order to establish the likely percentage demand from the non-domestic sector. A foreshore lease was obtained from the Department of Marine. Maritime archaeological assessment and a monitoring programme of the Garavogue River and Estuary were prepared in accordance with a requirement of the E.I.S. Certification.
The main contract involved the provision of a main pumping station, waste water treatment works, outfall, sludge treatment centre and the provision of sludge management facilities for al towns and villages in the county. The contract was a ‘Design Build and Operate’ form of contract with an operation and maintenance period of 20 years. Jennings O’Donovan & Partners with JB Barry & Partners Ltd are the clients representative and are responsible for the successful implementation of the project.
Construction on the plant commenced in November 2006.
Design Build Operate Contract (DBO)
Sligo County Council entered into a contract with Anglian Water International (AWI) Ltd on behalf of Anglian Water, Huntingdon, Cambridgeshire, England for the design, build and operation of this new treatment facility with a construction period of 2 years and an operational phase of 20 years.
To support the project development and operation, Anglian Water Group deployed two main sub-contracts; one was to a consortium comprising Coffey Construction Ltd, Galway as the Civil Contractor for the design and construction of all the civil and building works, and Enpure Ltd, Kettleswood Drive, Birmingham, England as Mechanical and Electrical Contractor for the process design and supply of all the mechanical and electrical equipment and commissioning.
The second sub-contract was awarded to Celtic Anglian Water Ltd, City West, Dublin, for the operation of the works on behalf of the client for a 20 year period.
Regional context
Sligo has been designated as a sludge hub centre and will therefore include a sludge acceptance facility and sludge treatment centre for sludge’s generated in County Sligo and it is expected to be able to receive biosolids for treatment from outside the county boundary.
Plant Operation
The sludge produced from the site and imported sludge must receive the appropriate treatment to reach the standards necessary to be classified as Class A biosolids and for reuse by spreading on agricultural land. This is achieved by pasteurisation and sludge digestion.
The treatment works will provide treatment to the highest standard including full secondary treatment supplemented by phosphorous removal and by disinfection using ultra-violet light.
Design Basis
Population Equivalent - 50,000
Dry Weather Flow - 145 1/s
Flow for Full Treatment - 434 1/s
Maximum Flow for Storm Treatment - 6569 1/s
Maximum Flow to Works 4.86 DWF - 703 1/s
Biological Oxygen Demand (BOD) - 3000 kg/d
Suspended Solids - 3000 kg/d
Orthophosphorous - 148 kg/d
Treatment Required
| Parameter Reduction | Concentration 95%ile |
Minimum % of Reduction Maximum |
|---|---|---|
| Biological Oxygen Demand (mg/1) | 25 | 50 |
| Suspended Solids (mg/1) | 35 | 60 |
| Chemical Oxygen Demand (mg/1) | 125 | 12 |
Phosphorus - TP (mg/1) 2 mg/1 annual average
Faecal Coliforms 250 MPN/100ml (spot Sample)
UV (Ultra Violet) treatment for bacterial reduction is provided to protect Mari culture activities in Sligo Bay area
Protecting Our Natural Habitats
First Winter Iceland Gull pictured this year at Deepwater Quay Sligo - these birds are seen annually in Sligo Harbour, but are rare in more southerly parts of Ireland and Europe Seeing these arctic wanderers at close quarters in Sligo Harbour is often the highlight of a trip to the north-west for visiting bird-watchers.
Photo: Birdwatch Sligo
Preserving Our Environment
Quality of Life in County Sligo
One of Sligo Local Authorities’ core objectives is to ensure a better quality of life for its citizens, and to achieve this we work with the local communities to maintain a high quality environment. County Sligo has one of the highest proportions of unpolluted river channel in the country. This high quality environment makes Sligo a more attractive place to live, and can also be a key determinant of economic prosperity in the entire county and region.
Water Quality
The introduction of the EU Water Framework Directive has placed a major focus on water quality. Under this directive, draft River Basin Management Plans have been prepared for all River Basin districts. These plans when finalised will govern how all waters, including rivers, lakes, groundwaters, estuaries and coastal waters are managed, so that at least good status is achieved in all water bodies by 2015. The plans are due to be adopted in December 2009. An extensive water quality monitoring programme is being carried out in County Sligo under the Water Framework Directive. This includes monitoring of 33 rivers and 6 lakes. The biological monitoring indicates that in the monitoring period 2004-2006, 85% of the river stations monitored in Sligo are classified as having satisfactory (i.e. Q4-5 or Q5) water quality.
A Groundwater Protection Scheme is currently being prepared for County Sligo by the Geological Survey of Ireland. The overall aim of this scheme will be to preserve the quality of groundwater in County Sligo, particularly for drinking water purposes, for the benefit of present and future generations.
Monitoring
Monitoring of all public water supplies in the county is ongoing in accordance with EC drinking water legislation. Minimum monitoring frequencies for drinking water depend on the size of the supply, i.e. the volume of water distributed per day. Sligo County Council works closely with the Health Service Executive and the Environmental Protection Agency to ensure the quality of water is maintained throughout the county.
The Greening of Sligo
Sligo Borough Council's Recreation and Amenity Programme
Sligo Borough Council is delivering a major programme of investment in the city’s recreational facilities to cater for a growing urban population. A range of new amenity projects is underway which will contribute enormously to the quality of life for our communities, and the greening of Sligo and its environs makes our city a desirable place to work and live. The provision of the new wastewater treatment facility is a prerequisite to the successful delivery of these amenities.
The Council’s Parks Department manages a rapidly increasing portfolio of amenity areas and other land:- 8 playing pitches, 6 playgrounds, a range of landscaped inner city areas, 33 acres of partially landscaped open space and 290 acres of undeveloped space incorporating woodland, pathways and agricultural pastureland.
The latest amenities to be completed are Seaview Park, Doorly Park and Forthill Park. These include modern natural grass/sand carpet playing pitches, new recreation areas and cycle ways. When the final phases of the parks and amenities developments are completed, Sligo City will boast quality recreational park areas with extensive quality parkland, a network of interconnecting pedestrian pathways and cycle ways and other amenities.
- Hillside Adventure Park Forthill, Sligo
Our Heritage
Sligo’s strategic setting in the landscape has been maintained through time, and its growth as a city will be shaped, by the availability of clean
water and the maintenance of a quality environment.
It is no accident that Sligo’s wetlands, coastal estuaries, rivers and lakes have been the focus of human civilisation for over 7,000 years. Wetland systems continue to be critical to the development and survival of human communities. This simply reflects the key role that water and wetlands have played throughout human life. The reality is that we still depend on our natural ecosystems to sustain us. The completion of the Sligo Main Drainage Scheme, has brought forward a mechanism where modern demands for growth can be met while minimizing the potential effect of that growth on the key natural resources that sustain our environment and communities.
Sustainability in Action
The real environmental benefit that accrues from this project relates to improved water quality in Sligo Harbour and the wider Sligo Bay complex that includes Drumcliff Bay and Ballisodare Bay. These estuaries provide essential ecosystem services which include; sediment and nutrient retention and export, climate change mitigation, water purification, reservoirs for biodiversity, wetland products such as shell fish as well as recreation, tourism and cultural values.
All these benefits are reliant on clean water and the contribution of the Sligo Main Drainage Scheme in this regard is significant. This is sustainability in action, and the scheme will improve water quality and the coastal environment of Sligo Bay for the benefit of the habitats and species that live there, and will make a huge contribution towards improving the quality of life of the people of Sligo City and County.
Sligeach - The Place of the Shels
The site of the Sligo’s new wastewater plant has a special significance in terms of local history, as the following extracts from local histories explain;
Wood Martin’s ‘History of Sligo’ states ‘the appellation of Sligo is apparently derived from sligeach, signifying Shelly River, from Slig, a shell.’ Wood Martin is of the opinion that large mounds of the shells of these creatures would have been discarded next to the local dwellings, and that these heaps of bright shells, glittering from a distance, were distinctive enough to give a name to the area around the crossing point on the river.
In her recent publication ‘The Streets of Sligo’ local historian Fiona Gallagher says ‘Sligo gets its name from the Sligachan shell, which was at one time very plentiful in the vicinity of the present town. The Four Masters refer to the nascent town as such in the 10th century, and shellfish middens are a common archaeological feature in the area around Sligo Bay. Being a large, shallow inlet, the area is particularly attractive to their growth, and as such this plentiful and nutritious food source was exploited by early settlers to the region. Certainly large deposits of shells were found in the 19th century when foundations were being dug for new buildings, and when the water mains from Kilsellagh were being laid in the 1980’s’.
Wood Martin ‘History of Sligo’1882
Fiona Gallagher ‘The Streets of Sligo’ 2008
Benefits of Sligo Wastewater Treatment Facility
- Compliance with the E.U. Directive 91/271/EEC – SI No 254 of 2001 (Urban Waste Water Treatment Regulations, 2001).
- Reduced threat of pollution of Sligo Bay.
- Elimination of unsightly discharge of untreated wastewater at the current outfall.
- Protection of existing mariculture in Sligo Bay.
- Protection of Blue Flag Status at Rosses Point.
- Enable Sligo to develop in a planned orderly manner for residential, commercial and industrial activities.
- Facilitate the development of a large area adjacent to the town centre for urban enhancement, recreation and industrial development.
Project Team
Client:
- Sligo County Council
Employers Representative:
- Jennings O’Donovan and Partners with JB Barry and Partners Ltd.
Main Contractor:
- Anglian Water International
Design and Build:
- Enpure Ltd, Kettleswood Drive, Birmingham, England
- Coffey Construction Ltd, Athenry, Co.Galway
- EPS Pumping and Treatment Systems Ltd, Mallow Co. Cork
Operation and Maintenance:
- Celtic Anglian Water Ltd
Anglian Water
Anglian Water International Ltd., a wholly owned subsidiary of the AWG Group of companies, was established to deliver wastewater services and high quality drinking water, in compliance with Domestic and EU regulation, and with a total commitment to sustainable development. As part of its international portfolio, Anglian Water International Ltd entered the Irish DBO market in 1998, and in 2004, successfully bid for the Sligo Main Drainage contract, delivering wastewater services to Sligo town and its environs.
Project Schedule
Contract Signing - 18th September 2006
Start Date - 30th October 2006
Completion Date - 29th January 2009
Operation and Maintenance Period - January 2009-January 2029
Funding of the Scheme
Cohesion Fund –Advance Contrat and Planning Phase
National Development Plan - Construction Stage of D.B.O.
Sligo County Council- Advance Works and D.B.O. Phase
Costs
Overall Design and Construction Costs - €40 Million
County Hall, Riverside,
Sligo,
Co. Sligo.
GPS : Irish Grid 169896, 335864
Tel:071 9111111
Fax:071 9141119 Email:info@sligococo.ie
