WDR & RT Taggart
DAWSON-WAM were engaged by NI Water to complete the construction of a new final effluent pump-away for Dungannon WwTW. The work involved the laying of 8500m of 630mm HPPE pipe and associated pumping station, outfall works and flow monitoring plant, to convey treated effluent to the River Blackwater. The scheme also included the laying of 3750m of 125mm HPPE pipe for a smaller sewerage pump-away laid along with the final effluent pipe over part of its route.
DAWSON-WAM completed the work generally by use of open cut trenching techniques, 95% of the pipe was laid in roads ranging from dual carriageway hard shoulders to rural roads. The other 5% was laid in fields adjacent to the treatment works. Any section of the 125mm sewerage main not laid in the combined trench with the 630mm pipe where laid using directional drilling. This minimised the effect on the public of pipeline construction and the significantly reduced the amount of traffic management and reinstatement required.
Two pumping stations were required to accommodate submersible pumps, measuring 3.6m dia x 5.5m deep and 3.0m x 6.5m deep. These were both constructed using a 'top down' construction technique. The shaft was setup and sunk by excavating inside to lower the precast rings to the required level, once achieved the base slab was cast and the ring back grouted to seal any ingress of water. This work was performed by Dawson WAM using our own specialist equipment and experienced workforce.
The Mechanical and Electrical design and installation was performed by Shaw Automation Ltd who were subcontracted by us to fulfil this role on the project. Shaw Automation are a local M & E contractor who we have used successfully on several other contracts for NIW.
Generally not subcontracting civil construction activities delivered NIW better quality product/service. DAWSON-WAM in-house resources delivered successful project management, site supervision, resource allocation of plant, equipment, labour and efficient programme control.
We had extensive input to design process as construction representatives on Framework delivery team. We carried out all functions from contractor site screening reports, needs assessments, SI works/assessments, rehabilitation technique decision matrix compilation, Client proposal presentations to testing/commissioning. Design input includes buildability, constructability, SI assessments, optioneering, construction method assessment and determination. We proposed, presented and finalised solutions for NIW with our design consultants WDR & RT Taggart.