What is Ozone ?
Ozone naturally produced in the atmosphere. Three atomic ozone with an O3 symbol and a molecular weight of 48. This molecule is produced by the action of ultraviolet light (UV) or a high voltage charge on oxygen (O2).
This colorless gas was first discovered by schonbein in 1840.
Ozone has a nasty smell in high concentrations but is not sensible in less concentrations. It destroys germs through oxidation and destruction of their cell walls. Destruction of microorganisms such as spore, Bacteria, cyst and viruse without the need for long time is the advantage of ozone. The organic matter, like as shield, defenses and protects bacteria.
Hence, higher concentration of ozone is need to destroy bacteria surrounded by organic matter.
Ozone naturally turns into oxygen. Ozone’s half-life is low compared to other disinfectants. Ozonation water is capable to disinfect surfaces, equipments and raw materials. In the form of gas, ozone as a preservative can increase the shelf-life of products. Ozone is a powerful oxidizing agent and has many industrial applications.
Advantages of using this gas are as follows:
- Ozone can be produced easily and locally.
- Ozone is one of the most effective oxidizing agents.
- Ozone rapidly converted to oxygen and does not have any chemical residue.
- Ozone reaction does not produced any toxic material.
- Compared to other disinfectants, ozone is more efficient.
- Ozone affects a wide range of microorganisms.
- Ozone has low maintenance cost.
- Ozone does not need to consumables.
The mechanism of ozone production in the ozone generator is corona discharging.
The methods of ozone injection in water are carried out in two ways:
- Contact column method: ozone is injected into water from below column in the form of fine bubbles.
- Venture method: Venture is used to inject ozone in water and the concentration of ozone in water is adjustable from 1 to 4 ppm.
Ozone measurement methods:
- Measuring with kit: This device is used to measure soluble ozone in water. The DPD4 pill is used.
- Electronic sensors: Usually, this sensors have an output that can be connected to ozone generator, which allows you to control the amount of ozone in water.
Ozone is much powerful than chlorine and the most important point is elimination of all microorganisms regardless of its nature at a faster rate.
In 2001, the FDA issued authorization to use ozone as a direct food disinfectant. (FDA – FR VOL. 66 NO.123 PP.33829-33830, June 26, 2001) which made a tremendous transformation in the use of ozone in form of gas or soluble in water to reduce microbial, viral, fungal or nutrients protozoa.
Benefits of using ozone compared to other disinfectants:
- Higher oxidizing degree.
- Faster activity
- Less effect time
- Better performance
- The result are more favorable for sterilization than other method
- Ozone generators are permanent.
- There is no need for any primary substance except 220 V power.
- No transport and maintenance costs.
The effect of ozone on bacteria:
At higher doses, an attack on the cell wall of the bacteria, causes the rupture of the outer membrane and death of the bacteria.
The effect of ozone on Viruses:
Around the surface of each virus is a protein membrane called capsid. Each ozone molecule, penetrating through the protein coating, destroys the nucleic acid of the virus. At higher concentrations, ozone molecules can degrade and destroy the viral protein layer.
The effect of ozone on Fungi and Mold:
The effect of ozone on fungi is more than mold. There fore, less concentration is required to eliminate fungi.
Ozone compatible materials:
Ozone compatible materials include ceramics, glass, stainless steel L 316 & L 304, aluminum Teflon, ETFE, PTFE. and gortex.
Ozone incompatible materials:
Ozone causes the destruction of steel, copper, plastic rubber & etc . there fore, all pipes that ozone pass through it, must be made of stainless steel or aluminum.
The ozone limitation during 24 hours is:
0.05 ppm for hard work, 0.08 ppm for medium work and 0.1 ppm for light work. Be careful when using ozone.
It should be noted that the use of active oxygen in the food industry and drinking water was approved by the Ministry of Health and Medical Education of Iran (Food & Drug Administration) on 13/8/1382.
Ozone verification centers in the world:
US Food and Drug Administration (FDA) on June 26, 2012, approved the application of ozone as an antibacterial agent in the industry.
- Environmental protection Agency (EPA)
- Occupational safety and health administration (OSHA)
- National Institute of occupational safety (NIOS)
- Word health organization (WHO)
- Ministry of health and Medical Education of Iran