Highlights in Wastewater History, 1800s-1940s

Highlights in Wastewater History, 1800s-1940s

In the wastewater treatment universe, the time before the discovery of bacteria and viruses was rough. Really rough. Especially as waterways became more and more polluted with waste. Humans, however, knew intuitively that collecting and removing the waste would keep their environment clean and healthy. The discovery of microorganisms and their links to disease validated these ideas.

In the 1800s, forced by a deadly cholera outbreak, a big shift began – one that ultimately created the industry we know today. Read on to learn more about wastewater history from the 19^th through the turn of the 20^th century.

1. Cholera Outbreaks: From the early 1800s to today, cholera pandemics have ravaged the globe. The disease is believed to have originated in India in 1817; it then spread to Europe and North America in 1826, moving eventually to the rest of the world’s population. Caused by bacteria and spread via tainted water and food, cholera can cause severe diarrhea and dehydration. Without treatment, the disease can be fatal.
2. Link Found Between Bacteria and Disease: Microorganisms were first identified in the late 17^th century by Robert Hooke and Antonie van Leeuwenhoek, while the concept of “germ theory” was established by Louis Pasteur in the 1860s. But in 1876, scientist Robert Koch linked specific microbes to specific diseases and discovered that some of them – like cholera – spread via water.
3. Good Bacteria, Good Water Health: As researchers of the late 1800s learned more about microorganisms, they discovered that some types of bacteria could be used to naturally purify wastewater. At the time, folks were experimenting with lime, alum, and iron salts to settle sewage and improve water clarity. Unfortunately, those materials did nothing to remove dissolved solids and microbes. Thus came the dawn of percolating filters and the beginnings of aeration, along with the iconic Imhoff Tank.
4. Imhoff Settling Tanks: Slowly but surely, engineers in the early 1900s began to pay closer attention to wastewater filtration and management, incorporating technology like percolating filters in their designs. These early mechanical and biological advances led to the development of settling tanks – most notably, the Imhoff Tank, a two-story sewage treatment tank created in 1906 by Karl Imhoff that separates the effluent from the solids, which then turn into beneficial bacteria-rich sludge.

5 The Power of Activated Sludge: In 1913, Edward Ardern and W.T. Lockett uncovered the process of activated sludge. They experimented by treating sewage in a draw-and-fill reactor (today’s sequencing batch reactors), which produced a highly treated effluent. They then aerated the wastewater continuously for about a month and were able to achieve complete nitrification of the sampled material.

6 Commercial, Municipal Wastewater Treatment: From the 1920s-1930s, engineers ran with these new technologies. After World War I, they experimented with activated sludge and innovations like aeration tanks, diffusers, settling mechanisms, and other ways to make sludge better. By the 1940s-1950s, treatment plants used mechanical aerators and surface- and turbine-type aerators that were both efficient and scalable.

As scientists and engineers pushed sewage treatment advancements through the 1800-1900s, the wastewater industry as we know it was born. Post-World War II construction, urban infrastructure, and expansion were happening all over – and so was the specter of government regulations. Read about them in our next installment, “Highlights in Wastewater History, 1950s-2020s.”