• Home
• About
• Applications
• Technology
• Employment
• Calendar
• Contact

Applications

Applications of ozone include:

Drinking water treatment

Drinking water has traditionally been treated by passing it through filter beds and adding chlorine. Two issues are starting to affect the viability of the use of this approach on its own:

1. Certain pathogens, including cryptosporidium parvum and giardia lamblia, are resistant to chlorine treatment. The first of these goes through a spore-form, which has a very hard outer coat that is resistant to chemical attack. We have shown that this is attacked by OH radicals, which are released during the breakdown of ozone[1]. Cryptosporidiosis outbreaks are becoming more common: there was an outbreak in Wales in December 2005[2] and a second in New York linked to a water park in August 2005[3]. Ozone disinfects the water by killing bacteria and inactivating viruses present in the water; it has been shown to inactivate strains of poliovirus, adenoviruses, rotaviruses, and the viruses which cause vesicular stomatitis and encephalomyocarditis.

2.  Increased concern about endocrine-disrupting chemicals (from washing-up liquid to the Pill) having effects on sexual functions in mammals and other animals, and the presence of other bio-pollutants, such as pesticides, in drinking water. These chemicals are not removed efficiently (or at all) from drinking water by existing techniques. As a result of these issues municipal drinking water, in cities such as London and Dallas, is now treated by ozonation.

The need for ongoing chlorination is not an issue for bottling plants, where the aim is to bottle drinks under sterile conditions and to provide consumers with an un-chlorinated product. According to Beverage World magazine, about 95% of US water bottlers use ozone for disinfection.

Ozone can also remove undesirable organic sediments, soluble iron and manganese, inorganic components such as sulphides, cyanides, and nitrites, unwanted colours, and residual tastes and odours.

Consumer

Ozone can be injected into washing machines both to sterilise clothing and also to perform bleaching. Sterility is particularly important in hospitals. In a consumer environment, the use of ozone can reduce the required water temperature and the use of chemical bleaching agents.

Medical

There are a number of medical applications which require bleaching and sterilisation. For example, ozone can be used to clean the sterilised water distribution lines in renal dialysis units. It can also be used to treat hospital laundry to ensure disinfection.

Food and drink industry

In 2001 the U.S. FDA approved the use of ozone, in the gas or liquid phases, as an antimicrobial agent for direct contact with foods. It is steadily being adopted in a range of food sterilisation and preservation processes.  Research at Newcastle University has demonstrated that ozone can extend the shipping and shelf life of a range of vegetables, including tomatoes and potatoes. Typically, this can be carried out either during storage or shipment.

Semiconductor processing

There are two types of ozone delivery systems used in semiconductor manufacturing: ozone gas delivery systems and DIO3 (ozone dissolved in deionised water) delivery systems. Ozone gas systems are used widely in chemical vapour deposition (CVD) processes and in advanced processes such as atomic layer deposition (ALD). DIO3 delivery systems are used in photo-resist stripping, wafer cleaning and surface conditioning applications, as well as for ultra-thin oxide growth. The use of ozone can dramatically reduce the consumption of chemicals and deionised water compared to immersion RCA cleans.  Clarizon’s technology produces ozone at about 3 times the concentration of CCD technology, leading directly to higher reaction rates and wider process windows.

Swimming pool, spa and hot tub water treatment

Swimming pools and hot tubs are normally treated by adding flocculent, chlorine and pH buffers and by filtering. However, chlorination levels are often high and found unpleasant by many people. Alternatives to chlorination include passing the water through high intensity UV light and / or treating it with gaseous ozone. Ozonation systems is considered expensive for treating swimming pools, being used in more luxurious health spas, but it is now being used widely in small spas and hot tubs.

Recirculating water

There are a wide range of systems using recirculating water for cooling, ranging from (larger) building air conditioning systems to power stations. The recirculating water needs to be disinfected to eliminate pathogens, such as legionnaire’s disease, being cultured.

Waste and effluent treatment

Ozone is useful in the treatment of wastewaters such as sewage, effluent from industrial processes, and waters polluted with pesticides. The primary application of ozone in sewage treatment is disinfection (including bacteria and viruses), but it is also used to control odour, to aid in removal of suspended solids (without the addition of dissolved chemicals), to remove a range of organic chemicals that are potentially harmful and to improve the biodegradability of the wastewater.

Bleaching

Ozone can be used to bleach, for example, flour, Teflon, waxes and synthetic fibres. In the paper production industry, ozone has been widely introduced as a method of bleaching, which removes the need for orgonochlorine compounds and thereby avoids pollution. Partly as a result, the use of chlorine in the pulp and paper industry has fallen from 7% to 1% of total US chlorine usage.