Sir Joseph William Bazalgette CB (; 28 March 1819 – 15 March 1891) was an English civil engineer. As chief engineer of London's Metropolitan Board of Works, his major achievement was the creation (in response to the Great Stink of 1858) of a sewerage system for central London which was instrumental in relieving the city of cholera epidemics, while beginning to clean the River Thames. He was also the designer of Hammersmith Bridge.
Early life
Bazalgette was born in Hill Lodge, Clay Hill, Enfield, London, the son of Joseph William Bazalgette (1783–1849), a retired Royal Navy captain, and Theresa Philo, born Pilton (1796–1850), and was the grandson of a French Protestant immigrant who had become wealthy.
In 1827, when Joseph was eight years old, the family moved into a newly-built house in Hamilton Terrace, St. John's Wood, London. He spent his early career articled to the noted engineer Sir John Macneill, working on railway projects and amassed sufficient experience (partly in China and Ireland) in land drainage and reclamation to enable him to set up his own London consulting practice in 1842.
In 1845, the house in Hamilton Terrace was sold, and Joseph married Maria Kough, from County Kilkenny, in Ireland. At the time, he was working so hard on expanding the railway network that two years later, in 1847, he suffered a nervous breakdown.
In 1847, while he was recovering, London's Metropolitan Commission of Sewers ordered that all cesspits should be closed and that house drains should connect to sewers and empty into the Thames. As a result, a cholera epidemic ensued, killing 14,137 Londoners in 1849.
Bazalgette was appointed assistant surveyor to the Commission in 1849, taking over as Engineer in 1852 after his predecessor died of "harassing fatigues and anxieties." Soon after, another cholera epidemic struck in 1853, killing 10,738. Medical opinion at the time held that cholera was caused by foul air: a so-called miasma. Physician Dr John Snow had earlier advanced a different explanation, which is now known to be correct: cholera was spread by contaminated water, but his view was not then generally accepted.
Championed by fellow engineer Isambard Kingdom Brunel, Bazalgette was appointed chief engineer of the commission's successor, the Metropolitan Board of Works, in 1856 (a post which he retained until the MBW was abolished and replaced by the London County Council in 1889). In 1858, the year of the Great Stink, Parliament passed an enabling act, despite the colossal expense of the project, and Bazalgette's proposals to revolutionise London's sewerage system began to be implemented. The expectation was that enclosed sewers would eliminate the stink ('miasma') that was thought to be the cause of cholera and, as a result, eliminate cholera epidemics.
Sewer works
At that time, the River Thames was little more than an open sewer, empty of any fish or other wildlife, and an apparent public health hazard to Londoners.
Bazalgette's solution (similar to a proposal made by painter John Martin 25 years earlier) was to construct a network of of enclosed underground brick main sewers to intercept sewage outflows, and of street sewers, to divert the raw sewage which flowed freely through the streets and thoroughfares of London to the river.
The plan included major pumping stations at Deptford (1864) and at Crossness (1865) on the Erith marshes, both on the south side of the Thames and at Abbey Mills (in the River Lea valley, 1868) and on the Chelsea Embankment (close to Grosvenor Bridge; 1875), north of the river. The outflows were diverted downstream, where they were collected in two large sewage outfall systems on the north and south sides of the Thames, called the Northern and Southern Outfall Sewers. The sewage from the Outfall Sewers was originally collected in balancing tanks in Beckton and Crossness, then dumped, untreated, into the Thames at high tide.
The system was opened by Edward, Prince of Wales in 1865, although the whole project was not completed for another ten years.
Partly as a result of the Princess Alice disaster, extensive sewage treatment facilities were built to replace the balancing tanks in Beckton and Crossness in 1900.
The basic premise of this expensive project, that miasma spread cholera infection, was wrong. However, the new sewer system's unintended consequence was removing the causal bacterium from the water supply, thereby eliminating cholera in areas served by the sewers. Instead of the incorrect premise causing the project to fail, the new sewers mostly eliminated cholera, and also decreased the incidence of typhus and typhoid epidemics.