Costain is involved in a major project in Liverpool's Docklands as it seeks to ensure that the city's efficient treatment of waste water continues uninterrupted into the future.

As part of a consortium with Galliford Try and Atkins it is now well into a £200 million contract for United Utilities (UU) to upgrade and expand Liverpool Wastewater Treatment Works (WWTW) at Sandon Dock.

The existing WWTW equipment has a limited remaining asset life and is in need of upgrade, says Andy Fielding, Costain's Construction Manager on the project. Costain, with its partners GallifordTry, Atkins and United Utilities, has undertaken refurbishment work to keep the plant performing, but more substantial measures are required.

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These will include replacing many plant items including the current inlet pumps, which lift wastewater from sewer level, with larger, more robust machinery. Other improvement works will extend the existing plant’s usage for a further 15-20 years. The existing site has to remain operational throughout all these works.

In order to ensure process reliability, the WWTW will be extended into the neighbouring Wellington Dock. This dock has been dredged and filled with sand. After sand fill around 1000 concrete piles 20 metres long are being sunk to the bedrock under the dock. The new dock area will be used to build a new SBR (Sequencing Batch Reactor) process tank and will sit as a 'floating' construction, atop the capped piles.

To make maximum use of the available space, the SBR will be double stacked and is fed from a new SBR feed pumping station to high and low level distribution chamber.

(CD)