Ozone is an inorganic molecule also referred to as activated oxygen because it is composed of three atoms of oxygen bound together. It is generated by stimulating a flow of oxygen from ambient air, with high energy amounts and causing the atoms of oxygen to split and reorganize into new molecules, oxygen free radicals and O3 (ozone). More than a 100 industries daily use ozone in countless applications. From water treatment to manufacturing processes, equipment maintenance, odor treatment, and preservation of food and raw materials.
Usually in the form of a gas, it is largely used as a disinfecting agent because of its strong oxidation abilities. When it comes in contact with bacteria, ozone breaks through the cell membrane and neutralizes the bacteria’s essential components (RNA, DNA, enzymes and proteins) leading to its destruction. Not only is ozone a disinfection agent, it is also categorized as a sporicidal agent (kills spores), an algaecide (kills and prevents the growth of algae) and a virucide (destroys or inactivates viruses).
Log reduction Values
For most applications, a log reduction of 4 is sufficient on average. Since ozone is produced on site, there is no extra cost for handling and storing dangerous chemical substances. And ozone does not leave residue after treatment as the atoms of ozone O3 decompose back to oxygen O2. The gaseous spread of ozone allows to disinfect any surface and reaching out difficult spots. Be with low or high concentrations, ozone is able to kill bacteria, viruses and spores.
Biological Lethal Coefficients of Common Disinfectants
|Disinfectant||Enterobacteria||Virus||Bacterial Spores||Amoebic Cysts|
*BLC: high value= high disinfection power
The use of Ozone is very appropriate for medical applications as it is more effective to sterilize large air volumes (like waiting rooms or treatment rooms) from bacteria and viruses compared to other air treatment alternatives. Ozone sterilization is good to preventing the spread of germs and pathogens in patient rooms by cleaning before and after new patients come to the rooms. And certain areas such as corridors, waiting rooms and bathrooms can be scheduled for ozone disinfection at nighttime, when they are free of patients and employees to allow the disinfection enough time to thoroughly sanitize the area. For rooms requiring a 6-log scale deactivation of living microbes like surgery rooms, the solution is to apply and monitor high concentrations of ozone in that room when closed, for many hours, letting the ozone disinfecting the area and paying close attention to the recommendations about exposure time.
One of the industries in which ozone is used the most is the food industry. In Oshiner previous article Ozone Applications in Water Treatment and Disinfection, we explained the disinfecting use of ozone in the food and beverage industry. Now we would like to talk about another application of ozone in that industry.
Ozone is vastly applied in the process of food storage as a gaseous fumigant. Starting in the pre-packaging stage of production of certain products such as meat and poultry, and the storage of directly harvested products, like potatoes, ozone is utilized to extend the shelf life of the products by reducing bacteria levels and controlling the spread of different pathogens. By eliminating the bacteria that cause the food to rot, ozone treatment allows to storage of harvested products for longer periods.
Odor Control and Smoke Removal
With the expansion of urban populations into industrial areas, odor control has rapidly become one of the most discussed topics within industrial environmental concerns. This situation is forcing businesses to consider the problem of odor pollution emanating from their factories. With its oxidation power, ozone has proven capable of eliminating different kind of industrial odors with a careful application custom-made for specific odors.
The same goes for ozone application on smoke. It can effectively break down the smoke molecules and separates them so that they can disperse, removing the room odor and smoke, and considerably making the area treated more comfortable and pleasant.
When operating an ozonator, it is important to know what the recommended concentration levels of ozone are. Generally, any level below 0.1 ppm is considered non-symptomatic, but higher concentrations can be tolerated. For example, exposure levels up to 1.0 ppm can be non-symptomatic, but only for up to 10 minutes. The 0.1 ppm point seems to be the accepted tolerance level.
In fact, the Occupational Safety and Health Administration (OSHA) standard is 0.1 ppm for a maximum of eight hours in the workplace. Anything beyond that level and, depending on exposure time, may cause symptoms including eye, nose and throat irritation, coughing, headache and shortness of breath.
OSHA has set specific guidelines for using ozone in the workplace and based on time-weighted averages. Ozone levels should not exceed the following standards: 0.10 ppm (parts per million) for an 8-hour work shift:
• 0.2 ppm for no more than 2 hours exposure
• 0.1 ppm for 8 hours per day exposure doing light work
• 0.08 ppm for 8 hours per day exposure doing moderate work
• 0.05 ppm for 8 hours per day exposure doing heavy work
Despite some concerns and warnings about exposure to high levels of ozone, the number of air treatment applications using ozone technology has increased significantly in recent years. Whether for public spaces disinfection, food storage or industrial odors control, ozone is proving to very useful in various industries.