New Ross Main Drainage Scheme

T J O’Connor & Associates were engaged by Wexford County Council in connection with a project to provide for the interception of raw sewage from 14 existing outfalls to the River Barrow and to convey this sewage onward to a new Wastewater Water treatment works in New Ross.

A new 600m long interceptor sewer was designed and constructed across the full length of the Quays at New Ross. This included a 300m long tunnelled section of 1,200mm diameter interceptor sewer. Pipe sizes range between 450mm and 1,200mm diameter.

The works were undertaken as part of two separate construction contracts comprising (mainly) a gravity pipelines contract covering most of the interceptor sewer and a contract to construct the Wastewater treatment plant.

The interceptor sewer contract included certain works to assist in the improvement of flood protection measures by providing for the collection and overflow of surface water from the lower parts of the town to the (pumped) interceptor in times of high tides. The works had to overcome difficult ground conditions associated with deep alluvial deposits.

For the pipeline and pumping station works, sheet piled trench support systems had to be used to provide safe working conditions. These supports extended through existing made ground on the quays into native to cut-off tidal ingress to the trenches/ tunnel shafts and pumping station wet wells.

Start/End Date:

Aug 2007 – Dec 2009

Contract Value:

€16M

Role:

Full Engineering Services as Client’s Representative

Key Features:

• Construction of 600m of interceptor sewer across the quays at New Ross and associated connections
• Construction of a 300m long tunnelled section of interceptor sewer at2m diameter
• New pumping station to transfer all of the flow up to 6 DWF to the Wastewater Treatment Plant via a 0km length of 600mm diameter rising main
• Preparation of an Environment Impact Statement
• Commissioning of site investigation works
• Mathematical Modelling (HydroWorks) of the sewerage system including flow and rainfall survey and model verification
• Preparation of Tender Documents using FIDIC Orange Book for the WwTW and IEI 3^rd Edition (CONDOC) for the pipelines contract
• Preparation of foreshore licence applications
• Part VIII planning Documentation
• Detailed design of sewerage works including works to upgrade existing Combined Sewer Overflows (CSOs)
• Project Supervisor Design Process duties under the Health and Safety Regulations
• Tender evaluation and report and recommendation on tenders received
• Construction Management and Supervision

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