This blog post illustrates drinking water guidelines according to NHMRC standards. However, to better understand the ozone water sanitization process, one must first understand how ozone works.
Ozone is generated when oxygen dissolves in water, and through this, bacteria and other waterborne pathogens are oxidized. Electricity or ultraviolet light split oxygen molecules into two oxygen atoms when they travel through air, providing the energy to split oxygen molecules. Ozone is created at the surface of the earth when electricity strikes and a bolt of lightning strikes the atmosphere and disintegrates oxygen atoms. In the upper atmosphere, sunlight reacts with oxygen to create the earth’s protective ozone layer.
It is also possible to produce ozone by electrolysis and chemical reactions, but UV and electrical ozone generators are the most common ones used for water treatment.
Ozone and Drinking Water Guidelines According to NHMRC
The National Health and Medical Research Council (NHMRC) is the main statutory authority under the Australian Government that conducts medical research.
In Australia, ozone has not been used for the primary disinfection of a large drinking water supply. But it’s a viable technology in many treatment plants. Natural organics react with ozone to form biodegradable compounds with lower molecular weights that promote bacterial growth in distribution systems. Many Australian water distribution systems may be impaired by increased water temperatures, which create an environment conducive to bacteria growth. Processes involving lower molecular weight compounds have been developed to prevent fouling.
After filtration through activated carbon granules, ozone can break up organic compounds with a high molecular weight. Low molecular weight compounds will make assimilable organic carbon (AOC) more available to bacteria that can use it to grow on it, thereby reducing organic concentrations in water.
Ozone is an alternative disinfectant that is less expensive than chlorine, and works perfectly in water treatment. Ozone is a long-time disinfectant that has been used for controlling taste, odor and color for many years.
It is highly automated and very reliable, even though ozone systems have highly technical components, requiring relatively little operator knowledge and time. However, ozone generators require skilled technicians for maintenance. It is important to ensure that ozone production and application facilities are designed to generate, apply, and control this gas, so that plant personnel are protected. Indoor levels of ozone should be continually monitored in plant facilities.
The table given below indicates that ozone has been shown to achieve 2 log reductions in target microbes based on published C.t values. These values are provided only as an illustration. The C.t value at a particular water treatment plant should be determined by the microbial risk assessment at that water treatment plant.
Note: These values are derived from published data and should be considered the minimum levels required for effective disinfection.
Based on above table, the important conclusion to draw is that ozone is more effective at killing viruses, Cryptosporidium, and Giardia than chlorine, chloramines, and chlorine dioxide.
One of nature’s most powerful oxidizers, ozone occurs naturally in the earth’s atmosphere. Through ozone water treatment, ozone helps ensure clean drinking water. In addition to its versatile use in various industries, ozone water treatment can also be used in the home.
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