Surviving pressure island
Adam Bateman of Earth Tech takes us through the tough challenges of updating the Isle of Man's water treatment works.
THE OFFICIAL opening of the Isle of Man’s Douglas Water Treatment Works took place earlier this year. It marked the culmination of six years of work on Isle of Man Water Authority’s (IoMWA) Crystal Project, and the earlier Sulby Water Treatment Works, by Earth Tech Engineering.
The updated works are integral to improving the island’s water supply and bringing the system into the 21st Century.
The work undertaken by the Crystal Project was to build a new treatment works at
Douglas, a new raw-water-supply pipeline. There was also an upgrade to the existing outfall pipeline, and various improvements to the water supply infrastructure. Earth Tech updated the systems, except for the raw-water pipeline.
The project was not without its challenges. The proposed single contract for the design and build of Sulby and Douglas was delayed by a lengthy planning and appeal process. This was a mixed blessing in that, although it held up work on Douglas, it did give the project team an opportunity to start work on the smaller Sulby works first.
Some key partnerships developed at Sulby, in particular the relationship with Lagan Construction, the main civil and structural engineering subcontractor. The intention at Douglas was to provide a similar installation to Sulby, generally working with the same mechanical and electrical equipment suppliers to provide operator confidence and maintenance commonality.
Sulby was awarded as an I Chem E Red Book (fixed price) contract. But towards the later stages of the project, IoMWA identified there would be more flexibility in awarding Douglas as an NEC ECC option C (target cost) contract.
The project at Douglas was to be the first to use a partnering approach to contracting work on the island. It also provided IoMWA with a vehicle for working more closely with Earth Tech on the detailed design phase.
This was seen as paramount given that Douglas was going to supply about 70% of the island’s population with water – the other 30% coming from Sulby.
The project team comprised members from IoMWA, Earth Tech and Lagan with assistance from Atkins, its design consultant. Another part of the team was made up of representatives from EC Harris and Holmes Grace, who provided the commercial auditing and planning supervisor roles for the authority.
The first few months of the scheme were interesting as the preliminary design and initial site works at Douglas coincided with the conclusion of the mechanical and electrical installation and commissioning at Sulby.
This period gave the authority’s representatives a more detailed hands-on understanding of what a modern water treatment works would look like.
The project ran relatively smoothly due to the combination of having a realistic budget of £22.5M, a reasonable programme of 33 months, and a solid team. But there were several interesting issues, some related to the geographical position of the Isle of Man.
The island is part of the British Isles, but it is not part of the UK or the EC. This means that, despite dealing in UK currency – although the island has its own monetary system – some economic and political factors must be considered.
For example, all the subcontractors employed by the project had to be registered as approved contractors with the Department of Trade and Industry. Also, anyone who worked on the island for more than a three-night stay in a year was required to get a work permit.
Getting the right paperwork in place involved much organisation by the site and office team to ensure it was done before various elements of work started on site. One of the biggest logistical exercises was getting plant, materials and equipment on site as the majority needed to be brought in by ferry. The island had sufficient earth-moving, aggregate and concrete batching facilities, but Lagan Construction had to bring its own heavy plant and cranes across from Northern Ireland. This was together with all the structural steel and cladding.
The majority of the mechanical and electrical equipment came from various parts of the UK. But some items, such as Earth Tech/Nordic Water’s patented lamella thickeners, were shipped in from Sweden.
Several local subcontractors were employed to provide building services installation. Some of the offshore subcontractors beefed up their workforce with personnel from the island.
The main drive was to ensure that subcontractors came across, brought the right equipment with them, and completed their workload in one visit.
The TT and the Manx Motorcycle grands prix in June and August also disturbed the work programme. The water treatment works is situated a few hundred metres from the start/finish line – while the roads were shut for racing, the site was landlocked.
The blocked roads meant that deliveries of larger mechanical and electrical items had to be planned carefully.
Completion of the project has provided clean drinking water, not only for the island’s population but also for the tens of thousands of tourists. Last year, for example, the island’s population swelled from about 80,000 to 130,000 during the centenary TT fortnight.
The IoMWA and its customers now have two reliable treatment facilities that will serve them for the next 15 to 20 years.
Adam Bateman is project manager for Earth Tech on the Douglas project.
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