Over 2,800 million litres of waste produced every day
349 sewage treatment works
Over 2,400 sewage pumping stations
Over 67,700 km (42,000 miles) of sewers
Europe’s largest sewage treatment works at Beckton, East London
Hot cooking fat solidifies when poured down the plughole. Each year over 1000 tonnes of fat cause 36,000 sewer and drain blockages. Dispose of the fat by letting it set in an old tin, and put in a bin.
Until around 1800 the river Thames had supported a large fishing industry, which caught and sold a wide range of species, including lobsters and salmon. But by 1805 only 150,000 cesspits had been built to serve London’s one million inhabitants and within a decade many householders had begun to illegally connect their overflowing cesspits to surface water drains which flowed into the river Thames, the main source of drinking water for London. The rising tide of sewage rendered it virtually lifeless – the river began to smell, especially in hot weather.
The state of the river became a well-publicised scandal that resulted in the Public Health Act of 1848. This established the Metropolitan Commission of Sewers. The new Commission quickly ordered a major survey of the London sewers, which were found to be inadequate and in major need of repair.
Outbreaks of cholera had occurred in 1832 but in 1849 a further outbreak, during which the death toll was estimated at 2,000 Londoners per week, prompted Dr John Snow and William Farr to conduct a study of the Broad Street Public Well in Golden Square, Soho. As a result, they realised contaminated water caused cholera and not “foul vapours” in the air as had been widely believed.
In an attempt to curb disease the Government passed the 1852 Metropolis Water Act. This introduced a number of measures including making the slow-sand filtration of water and the covering of service reservoirs mandatory and also ensuring that, in order to avoid proximity to sewage outfalls, the abstraction of water only took place above Teddington Lock on the River Thames.
In around 1854, the cash-strapped Commission of Sewers was replaced by the Metropolitan Board of Works whose Chief Engineer, Joseph Bazalgette, devised a sewage interception scheme designed to solve London’s sewage problem. Bazalgette planned to construct large intercepting sewers to collect flows from the existing river outfalls and convey the waste to East London. Here it could be stored in storage lagoons for up to 9 hours and released into the River on the ebb tide flow to the sea.
Bazalgette’s scheme was initially rejected on the grounds of cost, but in June 1858 the stench from the river Thames became so bad that it became impossible to continue business in the Houses of Parliament and action was demanded. As a result, the Prime Minister Benjamin Disraeli, rushed through an act allowing the Board of Works to raise the money to pay for the works by imposing charges on Londoners. Bazalgette’s plans had been so well honed that he was able to begin at once and by 1874 the system was fully operational.