2023-07-16 03:30:27
The tunnel, with a diameter of 7.2 meters, winds from west to east following the curves of the Thames. This “super-sewer”, as it is called in the UK, is to be tested in 2024 and fully operational by 2025.
It’s the biggest modernization of London’s sewer system since the second half of the 19th century, at the time designed by engineer Joseph Bazalgette following the infamous ‘Great Stink’ of 1858.
In July and August of that year, the combination of high temperatures and sewage flowing directly into the Thames plunged the city into a cloud of putrid air.
But in recent decades, sewage has once once more flowed into the river, due to lack of sewer capacity in the face of the British capital’s growing population.
Joseph Bazalgette’s sewerage system, a masterpiece of 19th century engineering, carried both sewage and rainwater, so the former often flowed into the Thames.
“No treatment”
“Every time it rains, even a light drizzle, the drains fill up and flow straight into the river,” says Taylor Geall of construction company Tideway, which is behind the project. “In an average year, 40 million tonnes of sewage flow into the Thames without any treatment.”
The old brick sewers are still in perfect condition, but they are not big enough.
The network was built when London had a population of four million, compared to nine million today.
The modernization, the cost of which amounts to 4.3 billion pounds sterling (5.02 billion euros), had become necessary.
The new tunnel will carry sewage only when the existing sewers are filled. Overflow points will allow waste water, which under the current system would have flowed into the Thames, to be diverted to the new tunnel.
“We will intercept and eliminate 95% of spills,” says Taylor Geall. “Once we’re done, the river won’t look much different, but it will provide a much healthier environment for the fish, marine mammals and birds that live there.”
Closed beaches
The last stages of the construction of this megaproject are taking place in the midst of controversy for the water sector, privatized in 1989, and accused of chronic under-investment in its networks.
According to the government environment agency, sewage spilled an average of 825 times a day last year into rivers and coastal areas across the UK.
Several beaches on the Isle of Wight, on the south coast of England, had to close during last summer’s heatwave due to high levels of bacteria in the water.
Surfers Against Sewage recently released a list of 83 beaches to avoid across the country due to sewage spills.
The government announced this week that water companies, along with other energy and waste operators, will face unlimited fines for polluting activities.
Thames Water, the London-area water management company that serves 15 million customers, was fined £3.3 million in early July for polluting waterways.
It is indebted to the tune of nearly 14 billion pounds sterling (16.3 billion euros). It is its customers who finance the “super-sewer” by deduction from their bills.
According to the PA news agency, Thames Water has already paid £32.4million in fines for pollution incidents in the Thames Valley and south-west London in other regulators’ lawsuits between 2017 and 2021.
For Mathew Frith, of the conservation organization London Wildlife Trust, the new sewer will make a “major contribution” to the restoration of the Thames. But, he says, it won’t solve the problem elsewhere in the country.
1689485052
#supersewer #London #pollution #Thames