More About Ozone and What Ozone Can be Used For

The universal disinfectant

Disinfection by 3-atomic oxygen called OZONE takes place by rupture of the cell wall - a more efficient method than Chlorine that depends upon diffusion into the cell protoplasm and inactivation of the enzymes. Ozone level of 0.4 ppm for 4 minutes has been shown to kill any bacteria, virus, mold and fungus.

When the effectiveness of Ozone as a disinfectant was measured, up to a certain dosage there was little or no disinfection. At higher levels the sanitizing effect increased greatly. For complete disinfection there has to be a surplus of residual Ozone in the solution to assure that every living microorganism has been contacted.

In the area of viruses there is yet to be discovered an antibiotic that is truly effective. There are indications that DNA viruses such as Herpes are implicated in human cancers, since they organize the genetic material of the host cell to produce new viruses. Ozone will inactivate viruses on contact even at very low residual concentrations. In case of polio only 0.012 ppm removes all viruses in less than 10 seconds.

Mold and mildew are easily controlled by Ozone in air and in water. Giardia and Cryptosporidium cysts are susceptible to Ozone but not effected by normal levels of Chlorine. Mold and mildew are easily controlled by Ozone in air and in water. Giardia and Cryptosporidium cysts are susceptible to Ozone but not effected by normal levels of Chlorine.

TASTE & ODOR CONTROL

Most tastes and odors in water supplies come from naturally occurring or manmade organic material contamination. Bacterial decomposition of humic material imparts taste to surface water, also the action of algae and actinomycetes give rise to objectionable tastes. Chlorination of humic material leads to chlorophenols that are far stronger odor and taste antigonists than the original phenol and the Chlorine. Most of these odors are removed by treatment with Ozone. Even some sulfur compounds such as hydrogen sulfide, mercaptans or organic sulfides can be oxidized to Sulfates with Ozone.

REMOVAL OF HEAVY METALS

Ozone oxidizes the transition metals to their higher oxidation state in which they usually form less soluble oxides, easy to separate by filtration. e.g. iron is usually in the ferrous state when it is dissolved in water. With ozone it yields ferric iron, further oxidized in water to Ferric Hydroxide that is very insoluble and precipitates out for filtration.

Other metals: Arsenic (in presence of Iron), Cadmium, Chromium, Cobalt, Copper, Lead, Manganese, Nickel, Zinc - can be treated in a similar way. At Ozone levels above 4 ppm however, Manganese will form soluble permanganate, showing up as a pink color.

COLOR REMOVAL

Surface waters are generally colored by natural organic materials such as humic, fulvic and tannic acids. These compounds result from the decay of vegetative materials and are generally related to condensation products of phenol like compounds; they have conjugated carbon/carbon double bonds. When the series of double bonds extend upwards of twenty, the color absorption shows up in the visible spectrum. Ozone is attracted to break organic double bonds. As more of these double bonds are eliminated, the color disappears. Surface water can usually be decolorized when treated with 2 to 4 ppm of Ozone.

OZONE vs. CHLORINE

In comparing disinfection efficiency, Ozone is effective 25 x more than Hypochlorous acid (HOCI), 2,500 x more than Hypochlorite (OCI) and 5,000 x more than Chloramine (NH₂CL). This is measured by comparison of CT constants - the Concentration & Time needed to kill 99.9% of all microorganisms. Chlorine reacts with organic materials to form Chlorine containing organics such as Chloroform, Carbon Tetrachloride, Chloromethane and others, generally known as Trihalomethanes (THMs).

Ozone reacts with Organics to break them down into simpler compounds. These (e.g. Oxalic Acid) do not readily break down all the way to Carbon Dioxide with just Ozone, but if subjected to bacterial degradation on activated charcoal, they will be removed. This water can be later treated with a low level of Chlorine say 0.2 - 0.3 ppm to maintain sanitation in the distribution system. This way no THMs will be formed. The THMs have been implicated as carcinogens in the development of Kidney, Bladder and Colon Cancer. The regulatory authorities are again decreasing the levels of THMs that can be in Community water systems. At the present time the limit is 0.05 ppm. Based on the scientific research, the level will be most likely soon lowered to 0.01 ppm.

Ozone does not react significantly with THMs as they are more resistant to oxidation - it takes a very long time to achieve full oxidation. Some THMs are removed as a result of physical sparging by the aeration action of the ozone/air mixture.

ALGAE REMOVAL

Ozonation of a water contaminated with Algae oxidizes and floats the Algae to the top of the reservoir. The ozone will also oxidize the metabolic by-products of the Algae and remove the undesirable odor and taste.

IMPROVED COAGULATION & TURBIDITY REMOVAL

Oxidation of dissolved organic materials by Ozone results in polar and charged molecules that can react with Polyvalent Aluminum or Calcium to form precipitates. Treatment of a surface water with up to 0.5 ppm of Ozone results in a decrease in turbidity, improved settleability and a reduction in the number of particles. Referred to as pre-ozonation this treatment destabilizes the colloid with a resultant reduction of the amount of coagulant needed to produce a clear filtrate.

OZONE REACTIONS TO ORGANICS

Ozone reacts rapidly with most simple aromatic compounds and unsaturated aliphatics, such as Vinyl Chloride, 1,1-dichloroethylene, trichloroethylene, p-dichlorobenzene, Benzene, etc. But it reacts slowly with complex aromatics and saturated aliphatics. Ozone will degrade many organic compounds, such as sugars, phenols, alcohols, and as it degrades these materials it returns to Oxygen.

Coupling Ozone with Hydrogen Peroxide will cause the formation of very active Hydroxyl ions which cause a nucleophilic attack on organic compounds. This can cause displacement of Halogens and other functional groups such as Amines and Sulfides. Coupling Ozone with Hydrogen Peroxide will cause the formation of very active Hydroxyl ions which cause a nucleophilic attack on organic compounds. This can cause displacement of Halogens and other functional groups such as Amines and Sulfides.

OZONE SOLUBILITY

The solubility of Ozone depends on the temperature of water and concentration of Ozone in the gas phase.

Table 1: mg/l (ppm) dissolved ozone

5°C

10°C

15°C

20°C

11.09

9.75

8.40

6.43

14.79

13.00

11.19

8.57

22.18

19.50

16.79

12.86

AIR TREATMENT

Ozone reacts rapidly with most odors, oxidizing them to less harmful elements or all the way to harmless Carbon Dioxide.

More and more of our furnishings and floor coverings are made from synthetic materials. Under the stagnant air conditions which prevail because of the lack of ventilation, decomposition products and solvents leach out of these synthetic materials and fill the indoor space. Much has been said about the "sick building syndrome" and this usually refers to institutional building. But they have basically the same problems as the private home. When odors are inhaled, they increase the demand for oxygen in the human body thus depleting the body of oxygen.

Ozone in natural settings is around 0.02 ppm, but it can be as high as 0.10 ppm. At this level it is capable of keeping pathogens in check and yet at this level ozone is not harmful to higher life forms such as fish, birds, animals or man. Ozone is not causing harm to the nature. Only a prolonged exposure to very unnatural high levels of ozone may lead to discomfort, later headache and coughing, telling you to leave the space and seek better air.

ECONOMIES

Ozone is effective against a large variety of water treatment problems. In general, the more problems in the water to be treated with ozone, the less an ozonation system costs when compared to other more conventional treatment methods. When one is comparing the cost of an ozonation system to other treatment systems there are some key factors to consider; here are a few:

• There is no need to purchase, ship or store chemical oxidants or disinfectants
• There is no labor for handling.
• Many health and safety concerns are reduced or eliminated.
• Because ozone reacts so much more quickly there is opportunity for substantial savings in space requirements for the treatment system.
• Because ozone treatment design is flexible, one of the variety of installations can be adapted to any fit any design circumstance.
• It is likely that much of your existing treatment facilities are adaptable to an ozone based treatment system.
• The pay back of your investment can be surprisingly short.