Civil Engineering

GRAHAM completes Holywood pumping main replacement

GRAHAM completes Holywood pumping main replacement image
Holywood project

GRAHAM completes Holywood pumping main replacement for Northern Ireland Water using innovative first-time technology

Civil engineering contractor GRAHAM has completed an innovative pumping main replacement scheme at Holywood, using a structural spray lining technology seen for the first time in Northern Ireland.

The project, located at Holywood Bypass in Co. Down, involved the installation of a new foul pumping main transferring effluent from Holywood A Wastewater Pumping Station to Kinnegar Wastewater Treatment Works for treatment.

The works required the installation of 1.455km of pipework and 100m of structural spray lining to rehabilitate the existing pipe sections situated at the hard-shoulder of the busy A2 Holywood Bypass and under the existing Bangor to Belfast railway line while protecting a high pressure gas main into the Wastewater Treatment Works at Kinnegar.

Innovative structural lining technology

The structural spray lining used on the project is a new introduction in technology to Northern Ireland Water and a first to be carried out in Northern Ireland.

GRAHAM and its specialist subcontractor Waterworx Pipeline & Civils Ltd procured the innovative trenchless structural lining, which is used to rehabilitate sewerage pipelines. This proposed methodology was agreed in advance with NI Water as it significantly reduced the disruption of traffic flows on the 4-lane carriageway, the impact on the railway network and the constraints imposed of working near a 75bar high pressure gas main.

The project team was tasked with the works following a survey which revealed that sections of the Holywood A to Kinnegar pumping main had a life expectancy of 0 years, meaning a breach could happen at any time.

Methodologies for works in and around the 75bar high pressure gas main, the railway network and carriageway section were agreed in advance prior to commencement on site, where we worked closely with SGN, Translink and DfI Road Service.

Minimising disruption with stakeholder engagement

During the works, the need for a single lane closure on the existing Belfast to Bangor bound carriageway to facilitate the installation of the new main meant it was important that minimal disruption was caused to traffic flows during peak times. To achieve this, GRAHAM liaised closely with DfI Roads to monitor the impact daily and ensure disruption was minimised.

Throughout the works, GRAHAM also maintained continuous flow management operations of the Pumping Stations at Holywood minimising customer disruption.

The scheme formed part of the Northern Ireland Water IF019 Capital Delivery Framework Lot 3 for Northern Ireland Water, which has seen GRAHAM collaborate on several other schemes, including a £1.9m a new wastewater pumping station and storm screening facilities at Portaferry Road, Newtownards.

PJ Mc Caffrey, Contracts Director for GRAHAM, said:

“We’re delighted to have completed this complex installation, utilising an innovative approach working with NI Water to reduce the impacts of the works on the surrounding area.
Proactive engagement of key stakeholders was key to the scheme’s success, with complex interface management required to mitigate the significant impacts of road and rail closures as well as to protect the high-pressure gas main, an extremely sensitive element of the works.
PJ added: “Our aim is to deliver lasting impact on all of our projects and to transform and improve the built environment for the communities we serve. This scheme is a great example of innovation and our expertise in the water sector and we look forward to continuing our relationship with NI Water on future projects.”