Disinfection

Water disinfection means the removal, deactivation or killing of pathogenic microorganisms. Microorganisms are destroyed or deactivated, resulting in the termination of growth and reproduction. When microorganisms are not removed from drinking water, drinking water usage will cause people to fall ill.

The goal of disinfection of public water supplies is to eliminate the pathogens responsible for waterborne diseases. The transmission of diseases such as typhoid, paratyphoid fevers, and cholera can be controlled with treatments that substantially reduce the total number of viable microorganisms in the water.

While the concentration of organisms in drinking water after effective disinfection may be exceedingly small, sterilisation is not attempted. Sterilisation is not only impractical but it also cannot be maintained in the distribution system.

Public drinking water systems use different water treatment methods to provide safe drinking water for their communities.

After the water has been filtered, water treatment plants may add one or more chemical disinfectants (such as chlorine, chloramine, or chlorine dioxide) to kill any remaining parasites, bacteria, or viruses. To help keep water safe as it travels to homes and businesses, water treatment plants will ensure the water has low levels of the chemical disinfectant when it leaves the treatment plant. This remaining disinfectant kills germs in the pipes between the water treatment plant and people’s taps.

In addition to or instead of adding chlorine, chloramine, or chlorine dioxide, water treatment plants can also disinfect water using ultraviolet (UV) light or ozone. UV light and ozone work well to disinfect water in the treatment plant. However, these disinfection methods do not continue killing germs as water travels through the pipes between the treatment plant and people’s taps.