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Sewage Disposal

Sewage collection and disposal systems transport sewage through cities and other inhabited areas to sewage treatment plants to protect public health and prevent disease. Sewage is treated to control water pollution before discharge to surface waters.[1][2]

Contents

History

The historical focus of sewage treatment was on the conveyance of raw sewage to a natural body of water, e.g. a river or ocean, where it would be satisfactorily diluted and dissipated. Early human habitations were often built next to water sources. Rivers would often double as a crude form of natural sewage disposal.

Premodern systems[]

The first sanitation systems were built in the prehistoric Middle East, in the south-east of the modern country of Iran near Zabol. An inverted siphon system, along with glass covered clay pipes, was used for the first time in the palaces of Crete, Greece. It is still in working condition, after about 3000 years.

Higher population densities required more complex sewer collection and conveyance systems to maintain (somewhat) sanitary conditions in crowded cities. The ancient cities ofHarappa and Mohenjo-daro of the Indus Valley civilization constructed complex networks of brick-lined sewage drains from around 2600 BC and also had outdoor flush toiletsconnected to this network.

A large well and bathing platforms atHarappa, remains of the city's final phase of occupation from 2200 to 1900 BC.

The urban areas of the Indus Valley civilization provided public and private baths, sewage was disposed through underground drains built with precisely laid bricks, and a sophisticated water management system with numerous reservoirs was established. In the drainage systems, drains from houses were connected to wider public drains.[3]

Ancient Minoan civilization had stone sewers that were periodically flushed with clean water.

Roman towns and garrisons in the United Kingdom between 46 BC and 400 AD had complex sewer networks sometimes constructed out of hollowed-out elm logs, which were shaped so that they butted together with the down-stream pipe providing a socket for the upstream pipe.

A significant development was the construction of a network of sewers to collect waste water. In some cities, including Rome, Istanbul(Constantinople) and Fustat, networked ancient sewer systems continue to function today as collection systems for those cities' modernized sewer systems. Instead of flowing to a river or the sea, the pipes have been re-routed to modern sewer treatment facilities.

This basic system remained in place with little positive change, until the 16th century, when Sir John Harington invented the first flush toilet as a device for Queen Elizabeth I (his godmother) that released wastes into cesspools.

Despite this innovation, most cities did not have a functioning sewer system before the Industrial era, relying instead on nearby rivers or occasional rain showers to wash away the sewage from the streets. In some places, waste water simply ran down the streets, which had stepping stones to keep pedestrians out of the muck, and eventually drained as runoff into the local watershed.

Industrial Revolution era

The prevailing system was sufficient for the needs of early cities with few occupants, but the tremendous growth of cities during the Industrial Revolution quickly led to terriblyoverpolluted streets, which acted as a constant source for the outbreak of disease. As recently as the late 19th century sewerage systems in some parts of the highly industrialised United Kingdom were so inadequate that water-borne diseases such as cholera and typhoid remained a risk. In Merthyr Tydfil, a large town in South Wales, most houses discharged their sewage to individual cess-pits which persistently overflowed causing the pavements to be awash with foul sewage.[4]

As cities grew in the 19th century, increasing concerns were raised about public health.[5]:33–62 As part of a trend of municipal sanitation programs in the late 19th and 20th centuries, many cities constructed extensive sewer systems to help control outbreaks of disease such as typhoid and cholera.[2]:29–34

As Britain was the first country to industrialize, it was also the first to experience the disastrous consequences of major urbanisation and was the first to construct a modern sewerage system to mitigate the resultant unsanitary conditions.[citation needed] During the early 19th century, the River Thames was effectively an open sewer, leading to frequent outbreaks of cholera epidemics. Proposals to modernise the sewerage system had been made during 1856, but were neglected due to lack of funds. However, after the Great Stink of 1858, Parliament realised the urgency of the problem and resolved to create a modern sewerage system.

The civil engineer Joseph Bazalgette, constructed a modern sewerage system for London in the mid-19th century.

Joseph Bazalgette, a civil engineer and Chief Engineer of the Metropolitan Board of Works, was given responsibility for the work. He designed an extensive underground sewerage system that diverted waste to the Thames Estuary, downstream of the main centre of population. Six main interceptor sewers, totalling almost 100 miles (160 km) in length, were constructed, some incorporating stretches of London's 'lost' rivers. Three of these sewers were north of the river, the southernmost, low-level one being incorporated in the Thames Embankment. The Embankment also allowed new roads, new public gardens, and the Circle Line of the London Underground.

Wikipedia

Multimedia:

How We Got To Now with Steven Johnson is a six part PBS documentary series that reveals the story behind the remarkable ideas that made modern life possible; the unsung heroes that brought them into the world – and the unexpected and bizarre consequences each of these innovations has triggered.  He explains the series' debt to James Burke's Connections series.

 The Clean episode explains after English physician John Snow made the ground-breaking discovery in 1854 that Cholera wasn’t spread through the air but through water, the authorities finally learned one of the most important principles of public health: access to clean drinking water is crucial for preventing disease.  He also shows  nineteenth-century Chicago engineer named Ellis Chesbroughwho managed to come up with one of the most bizarre ideas in the history of civic engineering: lift the city to install a sewer).More extensive talk on series.

How we got to now : six innovations that made the modern world (PBS video six part series) by Steven Johnson (excerpt/ overview). UCSC library copy: S&E Stacks T14.5 .J64 2014. Colbert Report. audio interview. TEDx talk. BookTV/C-span talk. ebook download (use at own risk).