Once the enabling act was passed, the Metropolitan Board of Works could begin the task under the direction of its Chief Engineer, Joseph Bazalgette (1819-91).
Most schemes for removing London's sewage had planned to carry it inland so it could still be used as fertilizer, but Bazalgette realised this was impractical. Instead, he planned to build main sewers to collect the contents of the existing sewers and take their contents east to be discharged into the Thames.
Bazalgette's scheme consisted of three major elements:
- the intercepting sewers
- the pumping stations and the outfall sewers
- the pumping stations at Beckton and Crossness.
Each of these involved major feats of engineering.
From the intercepting sewers to the pumping stations
|Deptford Pumping Station. © NMM|
On either side of the Thames, three main intercepting sewers captured the sewage from all existing sewers and carried them by gravity eastwards to the pumping stations at Abbey Mills (for the north bank) and Deptford (for the south).
To the Thames via the outfall sewers
The pumping stations raised the sewage so it could be carried by gravity to the Thames. It flowed to the river in the massive pipes of the outfall sewers.
|The pipes of the Northern Outfall Sewer. © NMM|
|Building the Northern Outfall Sewer. © NMM|
The outfall sewers were a massive feat of engineering. The Northern Outfall Sewer was more than 6.5 km (4 miles) long, and crossed the marshes east of the River Lea.
|The Northern Outfall Sewer in Plaistow. © NMM|
For most of its length, the Northern Outfall Sewer was concealed within a massive embankment. Several bridges carried it across the River Lea and its branches. The scale of the work is still impressive today.
|The Pumping Station at Crossness. © NMM|
The Southern Outfall Sewer ran underground for much of its length from Deptford to Crossness. At Beckton and Crossness, the sewage was stored in huge reservoirs, from which it was released into the Thames at high tide.
The Thames Embankments
|Commencing work on the Thames Embankment. © NMM|
The Embankments on either side of the Thames were another benefit of Bazalgette's scheme. The idea of building embankments to reclaim marshy land along the riverbank had been debated for centuries, but little was done before Bazalgette.
His embankments concealed sections of his intercepting sewers, and avoided the huge cost and inconvenience of digging up central London streets. They reclaimed nearly 10 hectares (22 acres) of mud, and also concealed a section of the Metropolitan Railway, the world's first underground railway line.
|Landing materials to build the Embankment. © NMM|
The whole scheme took seven years to complete. Bazlgette's achievement was amazing even by modern standards. When completed in 1865, London had 2100 km (1300 miles) of sewers, including 130 km (82 miles) of the main intercepting sewers. Almost a century and a half later, London still relies on Bazalgette's sewers.
|The Northern Outfall Sewer east of Stratford. © NMM|