Northern Ireland: Dunmurry WWTW Dewatering Industrial Unit

DAWSON-WAM Ltd were the principle contractor for an extension to Dunmurry Waste Water Treatment Works, Belfast for Northern Ireland Water. The scheme incorporated the design and construction of a new industrial unit to cover sludge import facilities, sludge storage, sludge dewatering and cake loading.

Constructed on a compact brown field site the client’s land constraints resulted in the new industrial unit being built in challenging and varying ground conditions where one half of the new de-watering building required 3m deep RC columns constructed off the base of disused settlement tanks, while the other half used traditional slab construction techniques.

The building utilised galvanised structural steelwork to extend the design life of the building within a highly corrosive atmosphere. The roof pitched to 9m to provide sufficient room for mechanical plant which was served by the installation of a 3T overhead gantry crane.

Composite metal cladding to the building was chosen to match the existing buildings on site with skylights provided to minimise lighting costs to the client.

Full height partition walls divided the building into compartments to house three weigh-bridges and associated weigh-bridge pits, various pieces of mechanical de-watering equipment, electrical equipment and a fully enclosed motor control centre for plant operation.

Connecting pipework and ducting networks were designed and constructed below finished floor level to provide a safe and clutter free working environment for the end user.

Extensive liaison with the client was necessary on this congested site to maintain programme while avoiding any impact on the client’s operating requirements. Possible programme delays were mitigated by forward planning and early identification of potential problems such as the advance removal of asbestos from the site ahead of construction commencement.

Successful contract completion was achieved through careful planning with the client to manage the interface with the existing plant throughout construction and during the final commissioning of the equipment within the new industrial unit.