Project – Portswood

Value – £35 million

Brief – Portswood water treatment centre is situated in a residential suburb of Southampton. The plant was constructed in the mid 50’s to service the newly expanded suburb of Portswood. As the years went by, the suburb expanded, and the plant struggled to cope with the increase in volumes.

As the volumes increase, and the plant began to struggle, the odour became an issue. As such the plant was unable to maintain its permitted discharge quality.

Galliford Try were awarded the £35 million contract to increase the plant’s capacity and reduce the odour.

Caledonia were presented with several problems when engaged as the incumbent consultant for the project.

As the tanks were reaching the end of life, they were schedule for de-construction within 5 years of this project. We were challenged to find a solution that was both cost effective and environmentally efficient.

With the plant already operating well over capacity, another project brief was to ensure the operations of the plant were uninterrupted during construction. We recognised that the installation of the roofs would be a challenge.

The location of the site restricted any large vehicle movements through the access routes. Due to this, the traditional methods of “capping” the sludge tanks with GRP roofs were not possible, as these are fabricated in sections too large to transport.

Caledonia’s innovative approach was to design an aluminium geodesic dome which was fabricated off site in skeletal section which were transportable in standard lorries. The panel sections were also fabricated off site and were again transportable in normal loads. The selection of this material was both cost effective and fully recyclable.

In addition, the material is substantially lighter than other materials used in this specific application, enabling the contractor to construct the roofs adjacent to the tanks and simply lift them into position. This in turn reduced the need to work over the live sludge tanks.

Client – Galliford Try (AMP 5 framework – Southern Water)

Services – Project Management. Project Controls. Temporary Works. Contract administration, HAZOP & ALM assessments.