Advantages of Ozone
  • Ozone is the strongest oxidant and disinfectant available for the treatment of aqueous solutions and gaseous mixtures.
  • Although ozone is only partially soluble in water, it is sufficiently soluble and stable such that its oxidation or disinfectant properties can be fully utilized.
  • After ozone oxidizes or disinfects, it decomposes into oxygen.
  • Ozone reacts with a large variety of organic compounds resulting in oxygen-containing organic by-products.
  • Although ozone is the strongest oxidizing agent commercially available, it is safe to handle. The primary reason is that it cannot be stored and, therefore must be generated and used on-site.
  • Ozone in its gaseous phase is a proven deodorizer for a variety of odorous materials.
  • In treating potable water, wastewater, and landfill leachate, ozone has the proven ability to convert biorefractory organic materials to biodegradable materials. As a result, combining ozone oxidation with subsequent biological treatment can produce water or wastewater with lower concentrations of problematic organic compounds more cost-effectively than either process used individually.
  • Applying ozone to any medium (liquid or gaseous) does not add other chemicals.
  • Ozone, by itself, does not affect pH (ozone can oxidize the contaminants which are causing a pH adjustment)

Negatives of Ozone

Like every oxidant, ozone has its down-sides. However, it is important we clarify the actual negatives vs. the perceived “negatives” that arise from misuse.

Commonly stated “negatives”

  • material degredation
  • can harm people, pets, plants
  • oxidizes materials

In light of ozone’s effectiveness, are the three items really negatives, or do we just need to use it safely like electricity, or gasoline? All oxidizers will have similar “negative” effect if used improperly. Proper implementation is critical to achieving outstanding results in your process.

The real negatives are listed below

Half Life: Ozone is an unstable molecule which quickly changes back to oxygen. The time for half of the ozone in air to decompose (half-life) is 20-60 minutes depending on the temperature and humidity of the ambient air. The half-life in clean water is about the same. Note: the temperature, pH, and water quality will affect half-life.

Storage: Ozone cannot be stored or transported, but must be made on site. This requires feedgas preparation and
ozone generation equipment. it would be ideal if ozone could be contained in a bottle and delivered onsite. We just aren’t there yet.

When can a negative be a positive? Since ozone cannot be stored, it is not possible to have a large, potentially dangerous volume of oxidizer such as you can have for chlorine or hypochlorite. Ozone equipment, which is required for all ozone applications, can neither be “punctured” with a fork lift nor “tipped over.”

Ozone basics

The ozone industry is growing faster than ever, and ozone is constantly being implemented in new applications.

How Ozone Works

Because of the way that ozone reverts back to oxygen over time, ozone cannot be delivered in tanks. Instead, ozone is typically produced on-site by an ozone generator.

Ozone Generators
Ozone generators produce ozone by adding energy to oxygen molecules (O2), which cause the oxygen atoms to part ways and temporarily recombine with other O2 molecules creating ozone (O3).

Ozone in Action
Once ozone is produced it reacts with a pollutant, often long-chain carbon (organic) molecules, and breaks it down into less complex (and typically less harmful) molecules through a process called oxidation.

Safety

Ozone is attractive as an alternative to chemical processes like chlorine, which present significant safety challenges. Exposure to ozone has not been shown to present long-term health problems.
However, there are several governmental regulations regarding the use of ozone in a workplace. For more details please refer to the guidance note on ozone (EH38) issued by the Health and Safety Executive: View here

Ozone Fallacies

We have heard them all. Now it’s time we set the record straight. Below is a list of a few ozone fallacies we have heard over the years.

“Ozone will oxidize my metal pipes!”

This claim conjures an image of ozonated water running through pipes and when you come in the next morning, they are rusted through. This is not the case. pH level has more effect on corrosion rates of metals than most industry accepted dissolved ozone levels. While a powerful oxidizer, ozone has minimal effect on corrosion rates. Iron pipes that carry ozone gas, while not recommended, will last for months, or years, before any significant corrosion is present. For ozonated water, iron pipes will oxidize faster than water without ozone, but the pipes can last for years before needing replacement. GreenTeck Global recommends the use of ozone approved materials. Iron pipes are not ideal but they will not degrade within a few days or even weeks as most people would have you believe. The same is true for most rubber seals.

“The sky is blue because of ozone.”

Okay, this one is not related to our business, but we have heard it mentioned before so we will address it. While ozone is a blue gas, the sky is blue for a very different reason. The blue color of the sky is due to Rayleigh scattering. Blue light has a shorter wavelength than the other “rainbow colors”. This blue light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue. So the next time your kid asks “Why is the sky blue?” you will have the answer!

“Ozone does not have any residual”

This one is also false, but clarification is needed. Ozone has an extremely short half-life. This short half-life makes it very reactive and excellent at killing pathogens. In very clean water, ozone can last for several hours. In most food processing applications, ozone half-life is anywhere from 10-20 minutes. For wastewater applications, the ozone residual is dependent on the organic loading with high organic loading resulting in short ozone half-life.

“Ozone is Explosive”

This statement is also false but clarification is needed. For ozone concentrations produced by commercial and industrial grade ozone generator, ozone is NOT explosive. We have been working with ozone for 15 years not heard one instance where ozone caused an explosion. Believe us that if there ever was an explosion, it would make the front page of chemical companies newsletters for the next 10 years. Research by Kunihiko Koike and Masaharu Nifuku in Japan states that ozone can be made to explode at very high (greater than 10% by weight) and very low pressures (less than 10 Torr = 0.0013 atm). Note that these pressures not not used anywhere in industry as they are not practical. 10 Torr is essentially in outer space. (Sea level is 760 Torr = 1 atm)

Ozone and OPR

What is OPR?

ORP is a term used frequently in the water treatment & food processing industry. ORP stands for “Oxidation-Reduction Potential”. So what is that? The best definition I can give is that “ORP is a measure of the cleanliness of the water & its ability to break down contaminants”. It has a range of -2,000 to + 2,000 and units are in “mV” (millivolts). Since ozone is an oxidizer, we are only concerned with positive ORP levels (above 0 mV).
ORP sensors work by measuring the dissolved oxygen. More contaminants in the water result in less dissolved oxygen because the organics are consuming the oxygen and therefore, the lower the ORP level. The higher the ORP level, the more ability the water has to destroy foreign contaminants such as microbes, or carbon based contaminants. The chart on the left identifies ORP levels for various applications.

ORP Level (mV) Application
0 – 150 No practical use
150 – 250 Aquaculture
250 – 350 Cooling Towers
400 – 475 Swimming pools
450 – 600 Hot Tubs
600 Water Disinfection *
800 Water Sterilization **Water Sterilization **

ORP level can also be viewed as the level of bacterial activity of the water because a direct link occurs between ORP level and Coliform count in water. The chart to the right lists ORP levels and relative Coliform counts.

ORP Level Coliform count in 100 ml of water
200 300
300 36
400 3
600 0

ORP Disadvantages

ORP cannot be used as a direct indicator of dissolved ozone residual, except in very clean water applications.

ORP Advantages

ORP is a convenient measure of ozone’s ability to perform a chemical task. ORP is valid over a wide pH range, and ORP probes are rugged enough to be place into processes for in-line measurement. The probes can withstand process pressures in excess of 30 PSI.

ORP and Ozone

In a clean water system, using ORP to measure the dissolved ozone status works well. In our experience, however, even the strong oxidizing power of ozone in moderate turbidity (cloudiness) systems can result in ORP values far below expected and even negative (reducing) values. In general, monitoring ozone with ORP at the generator source works well but measuring dirty water becomes unreliable. Ozone detection kits are available and work well at the limit of approved concentrations for your application.

How does an ORP meter work?

An ORP meter measures very small voltages generated with a probe placed in ozonated water. The electrode is made of platinum or gold, which reversibly looses its electrons to the oxidizer. A voltage is generated which is compared to a silver (reference) electrode in a silver salt solution, similar to a pH probe. The more oxidizer available, the greater the voltage difference between the solutions.

Using Ozone in Air
  • Ozone is the strongest oxidant available for the treatment of odors.
  • Ozone decomposes into oxygen after it reacts with odors.
  • Ozone is a Green Technology!
  • Although ozone is the strongest oxidizing agent commercially available, it is safe to handle.
  • Ozone kills airborne pathogen & viruses.
  • Ozone gas is molecular resulting in penetration of small cracks & crevices that cannot be reached with traditional cleaning methods.
  • Ozone gas is molecular resulting in penetration of small cracks & crevices that cannot be reached with traditional cleaning methods.

Ozone Basics

The ozone industry is growing faster than ever, and ozone is constantly being implemented in new applications.

How Ozone Works

Because of the way that ozone reverts back to oxygen over time, ozone cannot be delivered in tanks. Instead, ozone is typically produced on-site by an ozone generator. Ozone Generators Ozone generators produce ozone by adding energy to oxygen molecules (O2), which cause the oxygen atoms to part ways and temporarily recombine with other O2 molecules creating ozone (O3). Ozone in Action Once ozone is produced it reacts with a pollutant, often long-chain carbon (organic) molecules, and breaks it down into less complex (and typically less harmful) molecules through a process called oxidation.

Safety

Ozone is attractive as an alternative to chemical processes like chlorine, which present significant safety challenges. Exposure to ozone has not been shown to present long-term health problems. In fact, the USDA and FDA have approved ozone for use with food meant for human consumption. However, there are several governmental regulations regarding the use of ozone in a workplace. For example:

  • OSHA requires that ozone levels around workers remain below 0.1 ppm
  • OSHA requires that an ambient ozone monitor be in use for generators that produce more than 5 g/hr.
  • The USDA and FDA regulate how ozone may be used in food.

Click here for more information about the USDA and FDA.
Click here for more information about OSHA In any ozone implementation where humans are present, it is important to make sure there is proper ventilation and/or ozone destruction. How Ozone Works

Ozone FAQs

What is ozone?

Ozone, (O3), sometimes called “activated oxygen”, contains three atoms of oxygen rather than the two atoms we normally breathe. Ozone is the second most powerful sterilizer in the world and can be used to destroy bacteria, viruses and odors. Interestingly ozone occurs quite readily in nature, most often as a result of lightning strikes that occur during thunderstorms. In fact the “fresh, clean, spring rain” smell that we notice after a storm most often results from nature’s creation of ozone. However, we are probably most familiar with ozone from reading about the “ozone layer” that circles the planet above the earth’s atmosphere. Here ozone is created by the sun’s ultra-violet rays. This serves to protect us from the ultra-violet radiation.

How does ozone work?

The third oxygen atom of ozone makes it extremely reactive. This atom readily attaches itself to other odor molecules. When contaminants such as odors, bacteria or viruses make contact with ozone, their chemical structure is changed to less odorous compounds. As more ozone attacks the remaining compounds, the odor is eventually destroyed. This process is called oxidation. Ozone essentially reverts back to oxygen after it is used. This makes it a very environmentally friendly oxidant.

How is ozone produced?

There are basically two methods of producing ozone…ultra-violet and corona discharge. Corona discharge creates ozone by applying high voltage to a metallic grid sandwiched between two dielectrics. The high voltage passes through the dielectric to a grounded screen/plate and in the process, creates ozone from oxygen present in the chamber. Ultra-violet (UV) light creates ozone when a wavelength at 254 nm (nano-meters) hits an oxygen atom. Both processes split oxygen molecules into single oxygen atoms (O). These atoms combine with another oxygen molecule (O2) to form ozone (O3).

How long does the ozone last?

As soon as ozone is formed in the generator and dispersed in a room, it will start to revert back to oxygen. This step occurs by several processes including the following: Oxidation reactions with an organic material such as odors or smoke. Reactions with bacteria etc., which again consumes ozone by oxidation reactions. Additionally ozone breaks down thermally. Higher temperatures destroy ozone quicker than lower temperatures. The ozone that remains is referred to as Residual ozone. “Residual” ozone created will return to oxygen usually within 30 minutes, in amounts equal to half its level. What this means is that after each subsequent 30 minute period there would be half as much residual ozone left at the end of the period as was present at the beginning of the period. This is similar to a geometric progression of 16;8;4;2;1. In practice the half life is usually less than 30 minutes due to temperature, dust, and other contaminants in the air. Therefore, ozone, while very powerful, doesn’t last long. It does its job and then disappears back into safe oxygen.

Will the odor come back?

No. If ozone is applied properly it destroys the source of the odor. Treatment times may vary depending on the strength of the odor but 98% of ozone treatments are successful. In the case of mildew the odor will return if you are unable to get rid of the moisture that is the source of the mildew.

What is the right level of ozone?

The right level is when all the generated ozone is being consumed. This only applies to continuous ozone use in occupied environments not for shock treating. However, this is difficult to attain because it becomes a balancing act. Initially the machine’s output is set high to get rid of the problem odor as quickly as possible. As this is being accomplished less ozone is required for the diminishing odor etc., thereby leaving some residual ozone in the air. If the machine output is not turned down, then more residual ozone will remain. If a strong smell of ozone is noticed, then there is more ozone present than is required. Simply decrease the rheostat (output level control). With ozone, MORE IS NOT CONSIDERED BETTER! One must be careful when using ozone in a occupied environment.NOTE: It is not necessary that ozone be detected by humans for it to be effective. Ozone can work even when humans are not able to smell it.

Is ozone harmful and what, if any, are the long term effects?

Ozone was discovered almost a two centuries ago, so a great deal is known about it. Several regulatory agencies, including the Health and Safety
Executive (HSE) , have stipulated that the safe allowable level of residual is 0.1 ppm (parts per million). Note that this permissible level is for continuous exposure throughout an entire 8 hour day. The temporary affects of such a low exposure would range from headaches, to sore throats, irritation in the eyes, and nose. No long term effects have ever been documented from ozone exposure. Ask us for an MSDS if desired.

How do ozone generators work?

The old cliche’ is pictures are worth a thousand words, so see this page on how ozone generators work.

Is ozone safe?

Ozone is safe if used correctly. However, high concentrations of ozone can cause health problems if proper safety measures are not taken. For information on the health effects of ozone, please check out this page.

How does ozone kill bacteria?

Ozone kills bacteria by destroying the cell wall of the bacteria. Once the cell wall is destroyed, the bacteria will be unable to survive. For more details, please check out our page on Ozone Effects on Bacteria.

What size generator do I need?

Picking the right ozone generator can be a daunting task. For residential generators, we have created a chart to make the process simple. It will allow you to pick the right generator based on your house size and odor type.

If you need help choosing an industrial generator, please feel free to contact us and we will do our best to find a unit that will fit your needs.

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