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Improve control of your disinfection process

Learning how to properly disinfect your water crucial to ensuring safe, great tasting water for your customers.

Disinfection is a cornerstone of the treatment process, and it comes with a unique set of challenges. Preliminary treatment involves adding oxidants to raw water in a process called preoxidation, or primary disinfection. This phase of the water treatment process is designed to achieve the following:

• Destroy or deactivate pathogens
• Prevent biogrowth on filter media, equipment and pipes
• Improve water taste and odor (T&O)
• Minimize the formation of disinfection byproducts (DBPs)
• Help remove dissolved metals, such as iron and manganese
• Aid coagulation



Several different oxidants/disinfectants are frequently used in a preoxidation phase, depending on the challenges a utility faces. Utilities must make difficult choices to economically and sufficiently inactivate harmful microbes, remove dissolved metals and total organic carbon (TOC), minimize DBP formation, and optimize treatment processes.

Chlorine is commonly used in the preoxidation phase if the source water is minimally contaminated with organics or contains a low concentration of difficult-to-treat microorganisms such as Giardia or Cryptosporidium. If the source water is more contaminated and challenging, chloramine or other disinfectants such as ozone or chlorine dioxide are used for primary disinfection and oxidation. There are also situations when chemical treatment is combined with ultraviolet light and several oxidants.

The preoxidation phase of disinfection will change depending on the organics and microorganisms in your source water.


Secondary or postfilter disinfection requires operators to maintain sufficient disinfectant residual at point of entry, which in the United States is the last control and regulatory reporting point before the first tap or customer in the distribution network. Because parts of the water distribution network may be in remote locations, where it’s challenging to deliver safe tap water, water utilities must choose the right disinfectant. This choice may vary with seasons and events affecting source water quality.

Proper post-filter disinfection will help ensure safe, clean drinking water.



Learn about Disinfection with Chlorine & Monochlorimine

Learn more about chlorine and chloramine disinfection, the most commonly used oxidants in primary and secondary disinfection.

Learn about Other Disinfectants

Explore the considerations, processes, and parameters behind other disinfectant treatments, including ozone, chlorine dioxide, and UV.

Learn about Disinfection By Products (DBP) Formation

Learn more about DBPs, the various screening methods available for DBPs, and option for prediction DBP Formation.