Ozone is an industrial gas like no other, unable to be stored and transported like other gases and therefore required to be produced onsite.
A triatomic molecule consisting of three oxygen atoms, ozone (O3) is also a gas used in a wealth of water treatment services and municipal drinking water systems.
An allotrope of oxygen, it is much less stable than O2. Ground-level ozone is an air pollutant with harmful effects on the respiratory systems of humans and animals, while ozone is a powerful oxidizing agent – far better than oxygen.
With many commercial and industrial applications, it is used in potable and non-potable water treatment, and as an industrial oxidant.
Ozone has rapidly gained public acceptance worldwide, with the introduction of modern ozone generating equipment.
Such technology makes it feasible to generate substantial concentrations of ozone for a multitude of applications.
Large quantities of ozone are produced commercially in an ozone generator, in the same manner that ozone is formed naturally by the discharge of electricity during a thunderstorm.
The passage of a high voltage, alternating electric discharge through a gas stream containing oxygen will result in the breakdown of molecular oxygen, to atomic oxygen.
Ozone produced commercially for oxidation reactions is always produced as a gas, from air at concentrations between 1-2% by weight, or from oxygen at concentrations greater than 2% and up to 8% or greater by weight.
Since ozone is highly reactive, and has a short shelf-life, it cannot be stored as a gas and transported – consequently ozone is always generated onsite for immediate use.
The largest use of ozone is in the preparation of pharmaceuticals, synthetic lubricants, as well as many other commercially useful organic compounds – where it is used to sever carbon-carbon bonds.
It is used for bleaching substances and for killing microorganisms in air and water sources. A score of municipal drinking water systems kill bacteria with ozone, instead of the more common chlorine.
Ozone does not form organochlorine compounds, nor does it remain in the water after treatment.
Where electrical power is abundant, ozone is a cost-effective method of treating water – once it has decayed, it leaves no taste or odour in drinking water.
Drinking water treatment
When ozone is applied as a gas for drinking water treatment, it is done primarily because of its oxidative strength.
This powerful oxidation potential allows ozone to be effective in the reduction or elimination of colour, after taste and odour, all of which may be fundamental problems associated with a specific water supply.
When properly applied at the start of a water treatment process, ozone will not lead to the formation of halogenated compounds such as Trihalomethanes (THMs), which are formed when chlorine is added to the raw water containing humic materials.
There are more than two thousand installations worldwide that use ozone to treat drinking water.
The application of ozone or ozone in combination with other chemicals for the treatment of malodorous air has a long history of success.
Typically, in wastewater treatment plants, foul air can be collected and treated with ozone to reduce the odour. Ozone is usually applied in combination with wet scrubbing equipment.
Pulp and paper
As the general negative reaction to the dispersion of waste effluents containing chlorinated disinfection by-products grows, the consideration of the use of ozone in the many phases of the pulping process grows.
It should be pointed out that the pulp and paper industry has been examining the use of ozone for many years.
High concentrations of ozone, created by high concentrations of pollution and daylight UV rays at the Earth’s surface, can harm lung function and irritate the respiratory system.
Exposure to ozone and the pollutants that produce it has been linked to premature death, asthma, bronchitis, heart attack, and other cardiopulmonary problems. Susceptible people can be adversely affected by ozone levels as low as 40 ppb.
Long-term exposure to ozone has been shown to increase risk of death from respiratory illness. Due to the strongly oxidizing properties of ozone, ozone is a primary irritant, affecting especially the eyes and respiratory systems and can be hazardous at even low concentrations.