Belle Greve Outfall – Guernsey, UK

Water and Sewage Facilities – Van Oord

Guernsey Water needed to replace two outdated wastewater outfalls that discharged wastewater from the Belle Greve Wastewater Centre into the sea. The project involved connecting 500-meter-long polyethylene pipe sections offshore and carefully placing concrete collars around the pipes for protection and to provide the necessary weight for submersion.

Van Oord was awarded the contract to install the two parallel outfall pipes and enlisted TWD to design the installation aids. In close collaborating with Van Oord, TWD designed a custom working platform compromising eight 6.1-meter pontoons connected by two truss frames. This platform facilitated the connection of the pipe sections and the installation of the concrete collars.

The project had a very tight schedule, giving TWD just two weeks to design the working platform and prepare it for fabrication, with construction needing to be completed four weeks later. TWD is proud to have ensured that the installation process offshore Guernsey started on time.

Project highlights

• Method engineering in collaboration with our client to find the most efficient working method
• Tools flexible enough to accommodate various pipe diameters and different types of ballast elements
• Designed to fit on modular pontoons for easy mobilization and transport
• Design of collar installation tools, pipe pulling connections, bend restrictors and other miscellaneous equipment to facilitate the handling of pipes and collars