The project was to carry storm water flows from Abbey Mills to Beckton Sewage Treatment Works in London.
The tanks were required to give critical storage of large volumes of Bentonite slurry which was used to lubricate the head of the 120-metre long ‘slurry closed face’ tunnel boring machine during its 7km journey underneath the city.
Each tank was specified to hold 1,300 tonnes of the slurry mixture, which has a density of 1,400kg/m3, and one of the critical performance criteria for the tanks was the ability to be dismantled and rebuilt at a different location in a very short period of time in order to move the slurry capacity along the route of the tunnel as the process progressed.
The Permastore tank system was seen as an ideal solution for the Lee Tunnel project, combining the benefits of a modular steel tank, high-quality, factory-applied coating and the flexibility of a site-bolted solution that could easily be relocated within a number of days.
Initially, just five tanks were constructed at the Beckton Site with the remaining nine constructed a few months into the project. The first five were than relocated to the Abbey Mill site. Once the tunnelling process was complete the tanks were dismantled and removed from site completely by Kirk’s in-house site teams.
Early involvement in the project meant Kirk was able to work closely with the client, reviewing the project requirements and providing recommendations on the most suitable combination of products, materials and configuration, thus maximising operational performance of the project while keeping down capital costs.
The entire project was delivered under a very tight timescale and was managed by the in–house engineering, project management and construction resources at Kirk Environmental in partnership with the team at MVB-JV and Thames Water.