Drinking water ozone

Ozone has been used for over 100 years both as a very efficient method for drinking water treatment and to improve drinking water quality. At present, ozonized drinking water is gaining acceptance worldwide, mainly as an alternative to traditional chemical substances.

In order to obtain drinking water ozone acts as the fastest and most effective natural oxidizing agent that has ever existed. It is a powerful bactericide, viricidal and fungicide. Ozone improves organoleptic properties of drinking water, such as odour, colour and taste. It kills microorganisms breaking by oxidation the capsid, or exterior protein shell (lipids). Chemical agents act by enzymatic poisoning of the vital centers, so ozone turns out to be from thousand times faster than chemical agents.

Some of those characteristics allow ozone to obtain surprising results in drinking water treatment, because of his powerful oxidation potential with conventional pollutants such as iron, manganese, proteins, amino acids or humic acids, components which degrade taste, colour and odour of water. Ozone also oxidizes organic micropollutants, such as detergents, phenols, hydrocarbon, pesticides, herbicides and mineral fertilizers.

The oxidating action of ozone can be presented in three different forms:

As direct oxidant, setting one of its oxygen atoms.

As an oxidant, setting its three oxygen atoms to a double or triple connection.

As catalyst of oxygen, accelerating the speed of the oxidation reactions in ozonized air.

Water treatment ozone

Water treatment with ozone has been used for over 100 years as a very efficient method for water purifying. At present, ozonized water is gaining acceptance worldwide, mainly as an alternative to traditional chemical substances.

In water treatment, ozone acts as the fastest and most effective natural oxidizing agent that has ever existed. It is a powerful bactericide, virucidal and fungicide. Ozone destroy microorganisms, breaking by oxidation the capsid, or exterior protein shell (lipids). Ozone is 12 times more soluble in water than O2. Chemical products act by enzymatic poisoning of the vital centers, so ozone turns out to be from thousand times faster than the aforementioned chemical agents.

Use of ozone in water treatment, it allows to obtain, among others, the following :

Aquaculture and fish-breeding

Complete decolorizing of water

Disinfection of bottles and containers

Disinfection of pipelines and implements

Substantial reduction of detergent contents

Complete elimination of phenols

Elimination of unpleasant tastes and odours

Elimination of nitrite compounds

Elimination of organic compounds such as pesticides, herbicides and phenols

Beverages bottling

Inactivation of viruses

Bottles and containers washing

Fruits and green vegetables washing

Precipitation of iron and manganese

BOD and COD reduction

Cooling towers

Food transformation

Ground water treatment

Drinking and waste water treatment

WASHING OF FRUITS AND VEGETABLES BY MEANS OF OZONE

The objective aimed by means of fruit washing procedure, it is reduction or removal of pesticides and microorganisms present in the fruit skin, wich are responsibles for part of the fruit wastage in its own commercialization process. Such losses are frequently produced because of diseases linked to the beginning of harvest.

Fruit washing or rinse just with water, it is a simple drag treatment. It reduces pesticides and parasites by means of the effect of water movement on the fruit. This system does not result really effective, and involves much water volume wasting in order to obtain larger efficiency. Moreover, it exists the problem of resulting waste water, polluted with the pesticides and microorganisms removed from fruit.

Addition of detergents into the water, it continues being a drag treatment, and it doesn’t exert by itself an oxidiative and disinfectant effect enough to secure absolute elimination of microorganisms, such as bacteria, virus, moulds, spores, etc. Therefore, not only a procedure to removal of pesticides by oxidizing is not being used, but also water consumption is much more substantial in order to reach such objective. And the extra problem that waste water spill implies in this case, it has to be seriously considered.

Once exposed the evident problems related to washing of fruit just with water, we propose an alternative, which is to take advantage of the insuperable benefits provided by the oxidative properties of ozono.

In 1975, Bailey and Col. noticed that ozone can oxidize multiple olefinic carbon and acetylenic carbon bonds. Aromatic, carbon-cyclical and heterocyclical molecules. Carbon-hydrogen bonds into alcohols, ethers, aldehydes, amines and hydrocarbons. Silicon-carbon, silicon-silicon and silicon-hygrogen bonds, and several types of carbon-metal bonds.

Among all the applications of the oxidative effect of ozone, it can be stand out the following ones:

Removal of iron and manganese.

Removal of disagreeable colour, taste and scents.

Improvement in flocculation stages.

Destruction of algae and control of its development.

Oxidation and elimination of phenol.

Removal of detergents.

Oxidation of pesticides.

Removal of dyes.

Removal of nitrogen compounds.

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Removal of dissolved metals.

Etc.

REMOVAL OF PESTICIDES

Ozonation of compounds dissolved into water, it can constitute by itself an advanced oxidazing process, in which operates the hydroxyl radical resulting from ozone decomposition catalyzed by hydroxyl ion, or initiated by the presence of other substance traces, such as transition metal cations.

In the ozonation process, two possible oxidizing action forms have to be considered:

Direct oxidation, due to reaction between ozone and dissolved compounds.

Indirect or radical oxidation, produced by the reaction between hydroxyl radicals formed during ozone decomposition and the dissolved compounds.

Application of direct or radical oxidizing forms to removal of compounds, it will depend on the nature of compounds, medium pH, and dossage of ozone.

Otherwise, ozonation processes have been extensively studied, as resulting of which kinetic models have been established, and there is great research on ozonation of individual compounds.

In the following table, some results concerning to ozonation of pesticides are shown:

Conclusion

Just as it has been described all along the present manual, ozone is an element that reacts very quickly with a great variety of microorganisms and any type of organic and inorganic matter susceptible to oxidation. Moreover, ozone treatments, because of its chemically unstable nature, do not generate undesirable by-products, just as it occurs when ussing other systems. According to what has been stated above, it can be secured that ozone is the best disinfectant and oxidizing agent, with due respect for the environment.