By Luke Carothers
For as long as humans have congregated into communities, there have been attempts to manipulate nature’s forces in a way that benefits the health and quality of life of the members in that group. For the ancient civilizations of the Indus Valley, this meant controlling water resources through public works projects such as wells, storage tanks, public baths, and early sewage removal systems. Later civilizations, such as the Greeks and Romans, designed and constructed aqueducts to ensure the flow of water into agricultural works and public spaces even when a drought was present.
However, environmental engineering considerations remained largely unchanged from the time of Rome’s fall to the Industrial Revolution. As human populations became more and more dense, engineers were struggling to design systems capable of providing a clean living environment, particularly to those living in working class communities.
This situation came to a head in London in the mid-1800s. Starting in the late 1700s, London’s population exploded as more and more people flocked to the cities for work in the burgeoning factories. With the population nearly tripling from 1 million residents to 3 million and the invention of flushing toilets, city engineers were facing a waste problem bigger than they had ever anticipated. To accommodate this population influx, engineers built hundreds of brick sewers that were designed to dump the waste on the shores of the River Thames. In many places, these brick “sewers” were nothing more than covered portions of the Fleet and Walbrook rivers. By the middle of the 18th century, these tributaries of the Thames were entirely bricked over for use as sewers, flowing directly into the Thames. Furthermore, the city was filled with some 200,000 cesspits where residents dumped their waste.
The result of such poor planning was an immense loss of human life. London experienced three separate Cholera outbreaks from 1831-1854 that claimed the lives of over 31,000 Londoners. Additionally, because the prevailing theory of disease was based on the presence of noxious odors, city officials dumped dangerous chemicals into the cesspits to control odor. The resulting gases led to fires and poisoning deaths.
To begin fighting back against these deaths, the city of London established the Metropolitan Commission of Sewers (MCS). This was significant because it consolidated commissions that had been operating since the time of King Henry VIII; it also paved the way for the passage of a law that required new buildings to be connected to the sewer system.
The most significant member of the MCS began as an assistant surveyor, but eventually came to lead the organization. Joseph Bazalgette was no stranger to London’s growing sewage problem. By 1856 Bazalgette completed plans for a new vision of London’s sewage system; his plan was hinged upon splitting the city into two zones on either side of the Thames. It also specified that small, local pipes that were roughly 3 feet wide would feed into larger, central pipes as large as 11 feet wide. The plan also included a series of pumping stations throughout the city.
Once Bazalgette’s plans were revised and made official, the need was dire. In the Summer of 1858, London experienced some of its hottest weather on record coupled with a prolonged drought. The resulting drop in the water level turned the river into what famous novelist Charles Dickens described as “a deadly sewer”. In fact, the smell coming from the Thames was so bad that the window curtains in the Parliament Building had to be soaked in chemicals to lessen the smell.
The onslaught of noxious fumes eventually wore the legislators down, and they quickly passed legislation to begin work on Bazalgette’s plan. Workers and draftsmen soon began work on the over 1,100 miles of additional sewers that spanned 82 miles. By the time London experienced its next Cholera outbreak, much of the city was connected to the new waste system. The outbreak occurred in one of the only remaining sections of the city that had not been connected to the new system, and the spread was largely confined to that disconnected area.
In fact, Bazalgette’s completed system is still used by the population of London today after two subsequent expansions in the 20th century. Although it is now struggling to contain the waste of London’s, Bazalgette’s system is a milestone in the history of environmental engineering, standing out as a pivotal moment where engineering rose to the challenges of rapid urbanization.
Luke Carothers is the Editor for Civil + Structural Engineer Media. If you want us to cover your project or want to feature your own article, he can be reached at firstname.lastname@example.org.