Massive machine will dig Newham’s new super sewer

A 300-foot tunnel boring machine that will be used to dig a new sewer under Newham has been switched on for the first time.

Experts from Thames Water visited the Herrenknecht factory in Germany to inspect the machine before it begins digging the �635 million Lee Tunnel next year.

The new tunnel — 80 metres below ground — will prevent 16 million tonnes of sewage entering the River Lee as a result of Victorian sewers that are not able to cope with heavy rainfall.

Lawrence Gosden, Thames Water’s head of capital delivery, said: “Tunnelling is a risky business, especially on a project of this scale, so it’s essential we use the best available technology and ensure every last detail meets our unique requirements.

“We face the challenge of boring the deepest tunnel in London at some of the highest groundwater pressures that a machine of this type has tunnelled in.

“We will be passing through four miles of the most abrasive ground, without any other shafts along the way.

“The Lee Tunnel is the first of two tunnels, which will collectively capture an average of 39 million tonnes a year of sewage from the 35 most polluting combined sewer overflows.

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“It will tackle discharges from London’s largest overflow at Abbey Mills in Stratford, which accounts for 40 per cent of the total discharge. That’s why we’re dealing with this — the worst one — first.”

From mid-June, the tunnelling machine will be transported to London, where it will be reassembled in sections at Beckton sewage treatment works, before it is lowered into the ground.

The cutting head is so large that lampposts and other obstacles on nearby streets will need to be moved to allow it to get to the site.

Tunnelling work is due to begin in January 2012 and is expected to finish in late 2013. The machine is likely to progress at a rate of 17 metres a day.