Common water disinfection techniques

Jan. 27, 2014

Common water disinfection methods include UV, chemicals such as chlorine, unscented bleach and chloramines, distillation, ozonation and, of course during times of crisis, boiling.

Under normal conditions in most parts of the U.S. for customers receiving municipally supplied water, processes are in place to disinfect water and customers can rest assured that their water has minimal amounts, if any, of viruses, bacteria, germs and pathogens once it is ready to be consumed. Common water disinfection methods include UV, chemicals such as chlorine, unscented bleach and chloramines, distillation, ozonation and, of course during times of crisis, boiling.

According to the U.S. EPA’s Emergency Disinfection of Drinking Water information, boiling water is "the surest method to make water safe to drink and kill disease-causing microorganisms like Giardia lamblia and Cryptosporidium, which are frequently found in rivers and lakes."

However, boiling water is viewed as a short-term solution particularly during times of floods, municipal plant failures and natural disaster events. This is not a practical way to ensure that your family is safe during normal circumstances or for large volumes of water.

Dealers can sell and service disinfection

Private water well owners will invariably require disinfection of their water supply before is it considered potable. Dealers can help end customers sanitize their well initially and then as part of an annual maintenance plan. This ongoing service will help minimize bacterial buildup and control unappealing taste and odors.

The most common sanitizing treatment for wells is shock chlorination. Often, a strong chlorine bleach (sodium hypochlorite) solution is used in the well and throughout the distribution piping. Unscented household chlorine bleach can be used to sanitize wells. Chlorine bleach is a sodium hypochlorite (NaOCl) solution containing approximately three to six percent available chlorine.

Of course, before any shock treatment is performed certain precautions and safety equipment must be used. And, you’ll need to know information about the well, including the volume of the water in the well; depth of the well; static water level; and size of casing.

Many customers who are concerned about bacteria and microorganisms in their water will be receptive to an ongoing disinfection treatment system to protect their families and improve the taste, odor and quality of their water.

UV systems are now a popular option in many areas of water treatment, including residential and light commercial settings. Most UV equipment includes a UV light source that is enclosed in a transparent protective sleeve. As water passes through a flow chamber and UV rays are introduced into the water supply, these rays will destroy bacteria and inactivate many viruses.

Many customers enjoy several benefits of UV, such as it disinfects water without adding chemicals, it does not change the taste or odor of the water and does not remove any beneficial minerals in the water. UV systems are most effective when used in partnership with filtration units, such as a carbon filter, water softener and reverse osmosis. Dealers will want to regularly check the unit’s UV transmissions (UVT) to make sure that the unit’s light is not being blocked and hampering its effectiveness.

Looking for articles on disinfection?

Water Technology and have published numerous technical articles on the topic of disinfection. Below are some that could be of interest to you.

In the January 2014 issue of Water Technology, Professor POU/POE answered this question: I’ve heard about sodium dichloroisocyanurate as a water disinfectant and want to know if it can be used in a POU or POE drinking water treatment system.

Have a private well that you are helping a customer prepare for shock treatment. Read this article here.

And, our Technical Editor Dr. Joseph Cotruvo covered the topic of disinfectants in a recent Contaminant of the Month. Read the facts about common disinfectants used in water treatment here.

WQA’s Certification Action Line from the October 2013 issue addressed ozone. See if you know all the key information here.

When individuals ingest or are exposed to certain microorganisms, including pathogenic bacteria, viruses and protozoa, in enough quantity over a certain period of time through water, health risks could surface. E. coli, which is a member of the coliform bacteria group, is one common threat; however, the list of microorganisms that can be present in water is extensive.

Every year millions of people contract waterborne diseases. Harmful microbes can appear in any water system at any time if the conditions are right. Make sure customers are educated and safe throughout the year and not only when emergency situations arise.

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