For thousands of years, humans have treated drinking water in one way or another. The idea of drinking water treatment originally focused on improving the qualities and appearance of the water. However, with the advancements of science the focus of drinking water treatment changed to make the water safer for consumption. Modern drinking water treatment processes have greatly reduced the number of illnesses and diseases caused by unpurified water.
Early history of water treatment shows that it focused on the aesthetic qualities of drinking water. Methods to improve the taste and smell of water were recorded as early as 4,000 B.C. Ancient Greek writings showed treatment methods including ...view middle of the document...
S. during the 1900’s focused on reducing turbidity. Filtration was a somewhat effective method to lower turbidity, but disinfectants like chlorine helped the most in reducing the number of waterborne disease outbreaks in the early 1900’s. In 1908, chlorine was used for the first time as a disinfectant in New Jersey (www.epa.gov).
Federal regulation of drinking water quality began in 1914 when the U.S. Public Health Service set standards for bacterial quality of drinking water. At first, the rules only applied to systems that provided drinking water on carriers like ships and trains. However, by 1962 all fifty states used some version of the Public Health Service standards for all types of public water systems (www.epa.gov).
By the late 1960’s, aesthetic problems, viruses, and chemicals identified by the Public Health Service were not the only concerns for drinking water. Many of the new chemicals being used for treating drinking water were accidentally being released into water supplies, streets, and leaking underground. This chemical contamination problem gained a lot of attention from Congress and the public during this time. This awareness soon led to the passage of many environmental and health laws, one of them being the Safe Drinking Water Act of 1974. After this law was passed, the number of water systems using safer methods of chemical treatment for drinking water grew (www.epa.gov).
Many techniques used today by drinking water treatment plants are the same methods that have been used for hundreds, or even thousands of years. However, newer and better treatment techniques have been introduced with modern plants. Recently, the CDC (Centers for Disease Control) named drinking water treatment as one of the most important public health advancements of the 20th century (www.epa.gov).
Drinking water treatment plants can vary on how many steps are in the treatment process, but usually there are four main steps: preliminary treatment, coagulation and settling (also known as flocculation), filtration, and final disinfection. California is a good example of these steps used by modern drinking water treatment plants (www.h2ou.com).
The first step is preliminary treatment. This could be any type of process the water goes through before the main treatment. During the preliminary treatment, screens may be used to remove rocks, sticks, leaves, or other debris. Chemicals may also be added to the water to control any growth of algae or other plants (www.h2ou.com).
The next step is coagulation and settling, which removes small particles that are made up of micro-organisms, silt (fine sand or clay), and other dangerous items in the water (http://www.h2ou.com). At this stage, treatment chemicals such as aluminum are also added to the water. Aluminum is the most commonly used chemical for this step of treatment. In the water, aluminum forms tiny globs called flocs. Bacteria, mud, and other particles stick to the flocs. The water is then sent into a large...