Taming the Thames: How London's Sewage System Changed the City's Fate

Get ready to dive into the depths of the grody yet fascinating world of sewage! From foul to fabulous, London's sewage system is a marvel of engineering that has kept the city running smoothly for over a century. Sure, it may not be the most glamorous topic, but don't let that deter you. Join us this week as we peel back the lid and explore the hidden underworld that lurks beneath the streets of London. It's time to flush away the misconceptions and dive into the quirky, humorous, and intriguing world of sewage. And for those of you who are Ted Lasso fans, this famous underground system was recently featured in their newest episode (quite funny seeing a team of footballers down in the sewers of London with their American football coach).

The construction of the London sewer system was prompted by a number of factors, including public health concerns, rapid population growth, and the increasing pollution of the River Thames.

During the 19th century, London's population was rapidly expanding due to urbanization and industrialization. The city was overcrowded and inadequate sanitation practices led to widespread water pollution and contamination.

The invention of the water closet had roughly 2 gallons of water being flushed into tributaries overwhelming cesspits which caused the Thames to overflow with waste. It essentially became an open sewer. This, in turn, caused outbreaks of waterborne diseases such as cholera and typhoid, resulting in high mortality rates and public health crises.

In 1854, a severe cholera outbreak known as the "Great Stink" occurred in London, which further highlighted the urgent need for improved sanitation measures. The smell from the polluted River Thames was so unbearable that it disrupted the functioning of the Houses of Parliament, located along the river, and forced them to temporarily close. This event pushed the government and public opinion to take action to address the city's sanitation problems.

As a result, the Metropolitan Board of Works (MBW) was established in 1855, and Sir Joseph Bazalgette, a renowned British civil engineer, was appointed as its Chief Engineer in 1856. Bazalgette was tasked with designing and constructing a modern sewerage system for London to improve sanitation, public health, and the quality of the River Thames. Bazalgette designed and oversaw the construction of a comprehensive sewerage system for London, which involved building an extensive network of underground tunnels, pipes, and chambers to collect and transport wastewater, stormwater, and sewage away from the city and into the River Thames for treatment or discharge.

His design included large brick-lined sewers, intercepting sewers, and pumping stations, which were considered innovative engineering solutions at the time. The construction of the London sewer system, which lasted from 1859 to 1875, was a significant undertaking and is often considered one of the greatest civil engineering achievements of the 19th century. It transformed London's sanitation and helped to mitigate the spread of waterborne diseases, greatly improving public health and living conditions in the city.

Integral to Bazalgette’s plans was constructing four major pumping stations to lift sewage from low lying sewers for discharge eastwards. Believe it or not these pumping stations contain some of the most beautiful architecture in London. The Crossness pumping station and its Romanesque architecture, designed by James Watt & Co, contained four enormous powerful beam engines that raised the effluent from south of the river up 12 metres into a reservoir. The Abbey Mills pumping station, another masterfully crafted building with elaborate Italianate Gothic style architecture, pumped effluent from north of the river beyond city limits.

When completed in the mid-1870s, the new sewage network’s enclosed design, which captured both sewage and rainwater, virtually eliminated cholera. It is considered one of the most significant milestones in the history of public health and urban planning.

While this is an amazing success story for the 19th century, the sewage system, which has been in operation for 150 years, is facing significant challenges in the present due to the city's ever-growing population, now nearly 9 million strong. Despite efforts to manage the increasing volume of waste, millions of tons of raw sewage continue to overflow untreated into the Thames each year, particularly during extreme weather events. To address this issue, Tideway, a company responsible for managing London's sewer system, is constructing a "super sewer" called the Thames Tideway Tunnel. This ambitious project involves the construction of a 25-kilometer tunnel, stretching from Acton in the west to Beckton in the east, at depths ranging from 30 to 60 meters below ground level. The tunnel will utilize gravity to transfer the waste eastward for treatment, and it is expected to be completed in 2024. As part of the project, a new barrier is also planned for the river near Blackfriars Bridge, which will be named Bazalgette Embankment in honor of Sir Joseph Bazalgette, the visionary engineer who designed London's original sewer system over a century ago.

This new undertaking marks a significant step forward in the ongoing efforts to modernize and upgrade London's sewage infrastructure to meet the demands of its growing population and environmental challenges.

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