The Backstory of Chlorine

From time to time, our ratepayers have questions about the usage of chlorine in drinking water. This is understandable and gives us the opportunity to discuss how this chemical is so important to the safety and overall quality of our water system.

Chlorine is by far the most commonly used chemical nationwide for the disinfection of water supplies. In a 2018 report from the American Water Works Association, more than 80 percent of water systems in the U.S. used chlorine as a primary disinfectant.

Chlorination has been so successful that freedom from epidemics of waterborne diseases is now taken for granted throughout the nation. Having said that, it’s natural to wonder what illnesses chlorine protects us against.

Researchers have identified the main diseases that can be controlled by water treatment and chemical disinfection:

Globally, poor water quality remains a major threat to human health. Each year, 11–21 million persons contract typhoid fever after consuming contaminated water, and about 200,000 of those individuals die as a result. Additionally, 485,000 of the 1.6 million deaths that occur from diarrhea each year are thought to be a direct result of contaminated water.

So how did chlorination become so important to water treatment? The 1800s saw repeated outbreaks of cholera, dysentery, tuberculosis, typhoid fever, influenza, yellow fever, and malaria. For most of the 19th century, Americans suffered from waterborne diseases in large numbers. In fact, typhoid fever deaths were due almost exclusively to contaminated water. In 1900, 194 of every 100,000 U.S. residents died from tuberculosis, and most were residents of urban areas.

Yet, the early years of the 20th century saw extraordinary progress in water treatment because of chlorination. In 1908, Chicago, Illinois provided chlorination to contaminated river water. The first continuous use of chlorine for water disinfection in the United States occurred that same year in Jersey City, New Jersey. This was followed in 1912 by the first full-scale use of liquid chlorine for water disinfection at Niagara Falls, New York. This use of chlorine successfully eliminated recurring outbreaks of typhoid fever.

Between 1910 and 1920, it became possible to store and transport liquid chlorine. In the ensuing years, chlorination was quickly  adopted for use in municipal water systems across the United States. Typhoid fever and other waterborne diseases were largely reduced and even eradicated from U.S. cities.

Today, CUD applies chlorine in its everyday treatment processes at the K. Thomas Hutchinson Water Treatment Plant that serves Rutherford County.