A giant piece of London’s new super sewer was floated into place over the weekend by a specialist team working at Blackfriars Bridge.

The 3,700-tonne section of concrete culvert had to be built in the river 100m away and carefully manoeuvred into place due to space constraints under the bridge where it will be connected to the existing sewer system.

The huge structure will intercept thousands of tonnes of raw sewage from the Fleet combined sewer outflow (CSO) - which currently discharges into the River Thames – and redirect it into the new super sewer.

Peter Rouzel, Tideway’s Project Manager for Blackfriars Bridge Foreshore, said “After more than four years of planning, design and innovative engineering, it’s amazing to see this giant culvert come to life and float along the Thames. Through outstanding collaboration and teamwork, we’ve managed to achieve a unique solution that puts us one step closer to cleaning up the Thames. This feat of engineering will be looked at for years to come in the engineering world.”  

The 100 metre-long, nine-metre-high culvert was constructed within a cofferdam, a dry working area built into the river, which has occupied the north bank of the Thames for the last two years.

Approximately 1,200m3 of concrete was cast over three months to construct the culvert, creating a hollow structure which will now form the working area for the team as they build the rest of the structures required for site.

Viv Jones, Project Director for Tideway Central, a joint venture of Ferrovial Construction and Laing O’Rourke, added: “This is an historic milestone for the future of the River Thames. Our team, applying its ingenuity and a whole host of engineering expertise, has executed a bold and innovative solution to the significant challenges posed by this part of the river and London’s existing infrastructure. What we’ve accomplished here is a fitting addition to the system Bazalgette pioneered over 160 years ago.”

Tideway is the company building London’s super sewer, a 25km sewer tunnel that will prevent tens of millions of tonnes of sewage that currently pollute the tidal section of the River Thames in London every year.

Due for completion in 2025, the tunnel is being constructed from 24 sites across the city, from Acton in the west to Stratford in the east. More than 60 per cent of the tunnel has been built already, and the final section of the tunnel in East London will begin tunnelling later this year.