Tideway, the firm responsible for delivering London’s “super sewer”, the Thames Tideway Tunnel, announced its successful activation, on 14 February.
After ten years of construction the last of 21 connections has been made between the original Victorian sewers and the new 25km tunnel, bringing online a system which it is hoped will protect the tidal Thames from sewage pollution.
As with many urban locations worldwide, London’s sewer network has struggled to cope with the challenges of population growth and climate change, with rainfall regularly overwhelming the system and causing it to discharge into the Thames.
The new tunnel is intended to divert most of the existing sewage overflows away from the Thames, and drains 34 major sewer overflows in the city.
Tideway said activation of the fully-connected super sewer means 95 per cent of those spills are now being stopped.
The group also published its latest data on sewage prevented from entering the river since it first started connecting the super sewer: 5,500,000m³ has been captured to date. Data updates will be published regularly via a new tracker at www.tideway.london
Tideway CEO Andy Mitchell said: “This is another significant step forward – with this final connection complete, the super sewer is fully up and running and protecting the Thames. Our next step is to test it in storm conditions – which is why we are keeping a close eye on the weather – and we will do this over the coming months.
“We are at the start of a new chapter for London and its river. Our mission has always been about creating not just a tunnel, but a healthier, thriving environment for the river and its inhabitants. We look forward to seeing a real impact in the years to come and sharing everything we learn about the positive changes.”
The 25km-long super sewer connects to the 6.9km-long Lee Tunnel, a Thames Water asset – forming the ‘London Tideway Tunnel’ (LTT) system, running from Acton in West London to Abbey Mills in East London.
It starts at Acton Storm Tanks (West London), and follows the path of the Thames, passing through Hammersmith, Battersea, Southwark, Tower Bridge, and Limehouse, before heading towards Stratford. The tunnel then continues eastward past Tower Bridge, Limehouse, and towards Stratford, eventually terminating at the Abbey Mills Pumping Station in Stratford, where sewage is transferred to the Lee Tunnel and then on to the Beckton Sewage Treatment Works.
The work of bringing the full system online began in the autumn of 2024, when Tideway announced that the first four connections had led to 589,000 tonnes of storm sewage being captured by the LTT in a single, rainy 24-hour period.
Later, in December, Tideway said that 848,365 tonnes had been captured during heavy rainfall in another 24-hour period (November 27th).
