Map shows where London’s 16 mile £5,000,000,000 super sewer runs through

A map shows the route of London’s new super sewer, with just months to go until effluent will float through the mega structure for the first time.

Known as Thames Tideway Tunnel, the new sewer is almost ready to be launched after eight years of construction.

The 16 mile super sewer is designed to reduce raw sewage that flows into the Thames in bid to cut pollution in the river.

It’s designed to future-proof the capital’s aging sewage network dating back to the mid-19th century.

With the London population expected to hit 16million by 2160, the new tunnel is set to better protect River Thames from pollution, Tideway said.

Following tests this summer, the sewer will then be handed to Thames Water to run – despite the company leading the tables for raw sewage discharge in the UK.

Thames Water, which was feared to be on the brink of collapse last summer, is reportedly £14billion in debt.

The company argued it is ‘absolutely fair’ for them to take over the super sewer despite the ‘challenges’, Tessa Fayers, Thames Water’s operations director for Thames Valley and Home Counties told BBC News.

Why is the new sewer built?

Tens of millions of tonnes of untreated sewage is discharged into the Thames year after year.

In dry weather, sewage flows from millions of London toilets to the sewage treatment plants.

But when it rains, the system fills to the brim and overflow streams into River Thames, eventually finding its way into nature.

The new sewer will capture the most polluting overflows and take it to the Beckton sewage treatment plant.

Super sewer’s capacity will be 600 Olympic swimming pools of liquid.

Inside the tunnel

The super sewer is 24 feet wide – large enough for four cars side by side.

It starts from Acton in West London at the depth of 98 feet and flows downhill deep underground through central London boroughs.

The tunnel passes through several pumping stations and overground tunnel shafts on its way to Abbey Mills pumping station in East London, where the sewage passes through at 230 feet underground.

Instead of ending up in the Thames, the new main tunnel will transport and store sewage from 34 most polluting sewage outflows.

The main tunnel had to be dug deep to avoid existing London tunnels for roads and the Tube.

Some of the overground shaft sites have been turned into communal areas with art to make the ‘above-ground legacy’ of the super sewer visible, Tideway said.

Eventually, the sewage ends up at Beckton sewage treatment plant in East London, Europe’s biggest sewage site.

After treatment at Beckton, sewage will then be released into the Thames Estuary.

Super sewer construction

Construction started eight years ago after the sewer tunnel was given a go-ahead.

However, the Covid pandemic caused some delays – and racked up extra costs of £233million on top of the £4.9billion estimated costs.

Giant TBMs, tunnel boring machines, finished excavation in April 2022.

Super sewer is now complete after the 1,200 tonne concrete lid was lifted on top of a deep shaft at Abbey Mills in Stratford today, which took five hours of careful maneuvering.

The commissioning stage will begin in the summer, meaning the River Thames should see a reduction in storm sewage overflow within months.

Tideway’s CEO Andy Mitchell said: ‘This is the moment we’ve all been waiting for. The underground civil engineering on the Tideway project is now complete following eight years of dedicated hard work from all our teams working in the capital.  

‘There is still work to do – we need to finish some above-ground structures and, crucially, test the system – but this nonetheless marks an absolutely critical milestone for the Tideway project and for London.’

What the critics say

With more extreme weather like heavy rain and drought predicted to hit the UK due to climate change, even the super sewer could fill up.

Some critics have called the project overpriced.

Thames Water customers will end up footing the bill over the coming decades.

Their bills are set to increase by around £25 a year, BBC reports.

The super sewer is a ‘massive expensive pipe’, Theo Thomas from campaign group London Waterkeeper told the outlet.

He said the ‘Victorians would be a bit embarrassed that we haven’t come up with a more modern solution that that’.

Thomas argued the money should have been spent on ways to stop rain water flowing into the drains in the first place to stop it from mixing with raw sewage and filling up the system.

Rowers taking part in the Boat Race between Oxford and Cambridge were told to not enter River Thames after ‘alarmingly high levels’ of bacteria found in poo from Thames Water discharge.

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