Water treatment

Article By:

Boyer, Trevor H. School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, Arizona.

Last reviewed:March 2022

DOI:https://doi.org/10.1036/1097-8542.739400

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• Water treatment, published January 2021:Download PDF Get Adobe Acrobat Reader
• Water treatment, published June 2016:Download PDF Get Adobe Acrobat Reader

A sequence of physical and chemical processes used to transform various water sources into water that is safe for human consumption and is aesthetically pleasing. Water treatment is designed to remove particulate matter, chemicals, and microorganisms from water (Fig. 1). Water constituents that are harmful to human health are referred to as contaminants. In the United States, the specific constituents that must be removed from water, the extent of removal required, and the processes employed are guided by the Safe Drinking Water Act and water-quality goals. Water treatment is commonly classified by the water source, such as surface-water treatment and groundwater treatment. In addition, brackish groundwater, seawater, and treated wastewater can also be sources for water treatment. Water treatment employs both physical and chemical processes to ensure a multiple-barrier approach to contaminant removal. For example, water treatment uses a filtration process to physically remove microorganisms; and it uses a chemical disinfection process to inactivate microorganisms. The combination of multiple physical and chemical processes makes water treatment robust against changes in the composition of water sources. This is important because water treatment facilities are in place for decades.

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