Mutton Island waste water treatment works - design build operate & maintain contract

Galway City Council

This Scheme involves the upgrade of the existing Mutton Island WWTP from its current design capacity of 91 600 PE to 170 000 PE and the operation and maintenance of the plant for a period of 20 years. The upgrade works will be carried out during the O&M contract period. The upgrade works are expected to be by means of alterations to the existing process as the current site is highly constrained. The operator will also be responsible for management and disposal of the sludge produced at the works.The following information is intended only as a basic outline description of the Project, designed to assist prospective interested parties in deciding whether or not to apply for pre-qualification for the Project. It is emphasised that this document does not purport to contain all the information which such parties may require for that purpose or for the purposes of the tender itself.
General description of Mutton Island WWTW.
Mutton Island WWTW is located on Mutton Island, 1km south of South Park in Galway City. The existing WWTW is designed to serve a population equivalent (pe) of 91 600 and to treat final effluent to a BOD (Biochemical Oxygen Demand) level of 25mg/l and a TSS (Total Suspended Solids) level of 35 mg/l. Treated final treated effluent is pumped into Galway Bay by means of a 900 mm diameter pumping main which discharges to deep water approximately 420metres south of the island. Dilution and dispersion ensure that the water quality complies with the Bathing Water Quality Regulations at all stages of the tide. The WWTW was commissioned in September 2003.
The WWTW currently consists of the following components:
Inlet pumping station;
Treatment works building;
Primary effluent distribution chamber and primary sludge pumping station;
R/c Primary sedimentation tanks;
Intermediate pumping station;
R/c Surplus activated sludge holding tank;
Air blower building & rotary bar screen chamber;
R/c Aeration tank;
Secondary effluent distribution chamber & activated sludge PS.
Activated sludge pumping station;
R/c Concrete secondary sedimentation tanks;
R/c Picket fence thickener;
Reinforced concrete digester feed buffer tank;
R/c Primary digesters.
R/c Secondary digester;
Sludge pasteurisation unit;
Odour extraction bed;
Gas holder;
Outfall Pumping Station.
Administration Building, store etc.
General Description of Works Requirements.
Due to recent increased loading from the domestic and non-domestic sectors within Galway there is now a requirement to upgrade the existing WWTW to treat a peak demand of 170 000 p.e. The contract works include the design, supply, installation and construction of this upgrade. The works include for the operation and maintenance of the WWTW for a period of 20 years. The upgrade works will be undertaken concurrently with the first year of the Operation and Maintenance of the WWTW.
The site is constrained, being on a island, and so the upgrade of the WWTW is expected to be by means of alterations to existing processes with some upgrade to the hydraulic capacity.
The Operation and Maintenance Contract will include for the management and disposal (off site) of sludge generated at the Works.
The Contractor shall note that flows to the plant in the 20 year period may range from zero to the design flow and the plant shall be commissioned on this basis.
The Operation and Maintenance element of the Contract will include a significant monitoring requirement to confirm that the WWTW meets the required standards and also to identify payments due. Detailed requirements for monitoring for compliance, regulatory and payment purposes will be detailed in the Contract Documents.
The monitoring regimes for the waste water treatment plant, receiving water, sludge treatment and sludge reuse/disposal may be more demanding than the statutory requirements.
The appointed Contractor is to act as PSDP and PSCS.
Performance standards.
The design populations and associated hydraulic loadings for the WWTW are as indicated in the he table below;
Design parameter.
Population equivalent.
170 000 p.e.
Dry Weather Flow (DWF).
45 000 m3/day.
Flow to preliminary treatment.
270 000 m3/day.
Flow to Treatment.
135 000 m3/day.
Note: To register your interest in this notice and obtain any additional information please visit the eTenders Web Site at http://www.etenders.gov.ie/Search/Search_Switch.aspx?ID=228932.

Deadline
The time limit for receipt of tenders was 2011-09-27. The procurement was published on 2011-08-17.

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Procurement history
Date Document
2011-08-17 Contract notice
2011-08-31 Additional information
2011-10-10 Additional information