Southern Outfall Works x Crossness Pumping Station

In the early nineteenth century, London's water supply and the River Thames were heavily polluted with sewage. This resulted in several cholera outbreaks during which up to 20,000 people died annually. In 1858, Parliament instructed the newly formed Metropolitan Board of Works to remedy this situation.

Joseph Bazalgette, the Engineer of the Metropolitan Board of Works, was charged with finding a solution to these problems. His answer consisted of the construction of intercepting sewers north and south of the Thames, and immediately adjacent to the river. These were to receive the sewage from the sewers and drains which up to now had connected directly into the Thames. Until this time, Thames-side in central London was not protected by an embankment, and consisted of mud, shingle and sewage, onto which these various drains, outlets and ditches had discharged. Between 1856 and 1859, 82 miles of brick intercepting sewers were built below London's streets, all flowing eastwards. These were connected to over 450 miles of main sewers, themselves receiving the contents of 13,000 miles of small local sewers, dealing daily with half a million gallons of waste.

The major pumping stations were located at Abbey Mills near West Ham, and at Crossness itself on the south bank. The southern system contained three levels of intercepting sewers. The Low Level Sewer from Putney to Deptford picked up the Bermondsey branch and was joined by the High Level Sewer from Balham and the higher Effra Branch from Crystal Palace and Norwood; these combined at Deptford, and there lifted some twenty feet to discharge directly into the Thames at Deptford Creek. By 1860, work was proceeding on the Southern Outfall Sewer, and this, when complete, took the effluent from Deptford via Plumstead, and thence to Crossness. Here the sewage was pumped up into a reservoir 6.5 acres in extent by 17 feet deep, holding 27 million gallons, and was released at high tide to flow out on the ebb, towards the sea.

There was no attempt to treat the raw sewage: Bazalgette's concern was to get rid of it. Since the success of the enterprise rested on the use of the tides - two in each 24 hours - it follows that the reservoir had to be emptied in six hours, in order to utilise all of the ebb tide. In fact, to give some margin of safety, emptying had to take place in less time than this. And as soon as the ebb tide began to turn, the outlet culverts from the reservoir were closed by penstocks, and pumping continued, raising the incoming sewage from the deep-level culverts into the reservoir. Just before high tide in the river, the sluices connecting the reservoir and the river would be opened.

The Southern Outfall Works, as the complex at Crossness was originally called, was officially opened on April 4th 1865, by HRH The Prince of Wales (later Edward VII). Following an address by Joseph Bazalgette, the Royal party toured the works and reservoirs, and the Prince then turned the wheel which started the engines. Following that, in the true Victorian spirit, the "Prince and five hundred guests sat down to an excellent dejeuner, in one of the ancillary sheds, beside the Engine House".

Source: http://www.crossness.org.uk/