Northern Ireland: Aldergrove Trunk Main

NI Water Networks Project by DAWSON-WAM Ltd.

The project consisted of the upgrade of an existing gravity fed foul sewerage network which transfers flows from the Aldergrove catchment area to a new pumping station located within the grounds of the Antrim Forum. This had the added environmental advantage of removing outdated pipework from service that could potentially rupture and pollute nearby water courses and neighbouring organic farmland.

The main elements of the project were the construction of all civil works associated with laying 3.7km of 600mm diameter foul sewer and some 80nr manholes primarily along the residential area of the Dublin, Antrim and Lough Roads. The Dublin Road forms the main emergency services route to Belfast International Airport and as a result extensive traffic management was utilised in order to ensure the road was kept operational at all times throughout the course of the works. In addition 400m of 600mm diameter sewer was micro-tunnelled through Massereene Golf Course with depths varying from 7-11m. The micro-tunnelling element of the project had to be fast tracked to ensure completion in time for an all Ireland golf tournament being hosted at the club in early May. Through using trenchless technology reinstatement work within the golf course was kept to a minimum and ensured the course was in pristine condition in time for the prestigious event.

To enable the micro-tunnelling installation, 5nr 3.6m diameter and 4nr 2.4m diameter launch and reception shafts were installed by top-down construction. The shafts varied in depth from 7-11m and as they were installed from the top down there was no requirement for temporary works.

In addition 30 linear metres of sewer were laid under an operational railway line. Extensive consultation was held with NIR in order to obtain a possession period in which the lines were lifted and replaced upon completion of the sewer installation.

On completion reinstatement works included the re-surfacing and kerbing of roads, topsoiling/grass seeding of fields, re-erection of various forms of fencing and planting.