The Ozmotics Insider

Properly sizing an ozonation skid is a very important task when planning to use ozone for a particular application. Not adding enough ozone can undermine the effectiveness of the process while adding too much ozone can add unnecessary costs in terms of additional equipment needed to destroy ozone not consumed by the process.

Ozone Production Capacity Considerations:

Generally speaking there are four factors that determine how much ozone is required for a particular application:

Application: Different applications will require different concentrations of ozone. Even the same application will sometimes require a different concentration of ozone (i.e. wastewater treatment applications vary in their requirement for ozone depending on biological and chemical make-up of the effluent).

Contaminants: Ozone is a very strong oxidant, therefore ozone will react with both biological and non-biological contaminants and in general will be effective on both. The “one size fits all” approach cannot normally be used when sizing for anticipated ozone consumption during the particular process. Different elements react differently with ozone. Some applications need very small concentrations of ozone to oxidize contaminants while others will need much larger concentrations to complete the process. (i.e. certain biological organisms are harder to inactivate and therefore require higher ozone concentration).

Temperature and Pressure: Ozone is very effective at lower temperatures and less effective at higher temperatures. As such any application that requires higher temperatures to operate will be a less effective candidate for the use of ozone. Where the temperatures of the medium to be treated with ozone is above 40 degrees Celsius (104 Fahrenheit) the medium may need to be chilled in order to be more effectively treated by ozone.

While ozone works best at lower temperatures the extremely low temperatures are not desired either when considering using ozone.

Still, the optimum temperature for ozonation is strongly dependant on the type of contaminant present and there is no single number or range of temperature readings that produce the best result.

Alternatively, ozone will dissolve better in a pressurized medium therefore elevating the pressure of the application can also benefit the process.

Flow and Capacity: The amount of ozone required to effectively treat the contamination will depend on the flow rate and capacity of the application. The faster the flow rate (measured in gallons per minute GPM or liters per minute LPM) the shorter the contact time between the ozone and the liquid will be thereby resulting in a higher concentration of ozone required. Same can be said for capacity. 10, 000 gallons of effluent to be treated will require more ozone to be injected than treating 1,000 gallons of the same.

Ozone Dosing – General Guidelines:

The following are general guidelines published by “Water & Waste Digest” magazine (http://www.wwdmag.com/).

- Bottled Water: Low to Mid-Range Residual: (0.05 ppm -0.3 ppm)
- Cooling Tower: Low to Mid-Range Residual: (0.05 ppm -0.3 ppm)
- Water Reclamation: Mid to High Range: (0.2 ppm -0.5+ ppm)
- Iron, Sulfur and Manganese Oxidation: Ultra Low Range: (below detectable levels)
- Water Reclamation for Odor Control Only: Low Range: (Less than 0.01 ppm)
- Bacteria Kill: Mid to High Range: (0.2 ppm -0.5+ ppm)

Sizing an Ozone Generator – General Guidelines:

The following are general guidelines for sizing the ozone injection skid based on the type of application (source: http://www.wwdmag.com/)

- Iron, Sulfur, Manganese Oxidation: 0.5 grams/hour (500 ppm) per 5 GPM flow capacity.
- Bottled water to maintain purity: 1 gram/hour per 5 GPM flow capacity.
- Killing bacteria: (100 cfu) = 1 gram per 1 GPM flow capacity.

Other Considerations When Sizing an Ozone Injection Skid:

There are several other factors that could influence the size of the ozonation skid required.

Type of Injection: The larger the contact area ozone has with the contaminant the more effective it will be. Air stone diffusers typically generate large ozone bubbles therefore decreasing the overall contact area. The Venturi injector is a much better technology as it creates many micro bubbles therefore increasing the contact area of ozone with the contaminant. Having a larger contact area will result in a more effective utilization of ozone therefore requiring less ozone to be injected.

Inline Versus Mixing Tank Design:With an inline treatment the entire flow of liquid is treated with the ozone. This means that the ozonation skid will be required to process a larger flow volume. Larger flow volumes will require a larger processing capacity (larger pumps, injectors, etc.). A larger ozonation skid will also require more ozone since the utilization to loss ratio of ozone will also be higher.

The multi-stage mixing tank design typically involves diverting a smaller portion of the flow to the ozonation skid. Ozone is injected and dissolved at a higher than required concentration. The concentrated ozonated flow is then mixed with the main body of water diluting the ozone concentration to the required levels.

Monitoring the Dissolved Concentration of Ozone:

In order to be effective ozone must be kept in a desired concentration within the medium to be treated. A low dissolved concentration will undermine the effectiveness of the ozone and too high a concentration will cause ozone to escape unused therefore requiring larger ozone destruct unit.

So how do you ensure the ozone concentration is maintained at the proper level?

ORP (oxidation-reduction potential) or a REDOX probe will measure the concentration of the dissolved ozone by measuring the oxidation potential of the medium. Since ozone is a strong oxidant agent , the oxidation potential of the medium measured will rise as the concentration of ozone increases. If the concentration levels of ozone decrease the oxidation potential will decrease as well.

Positioning the ORP probe strategically within the application infrastructure will give relatively accurate readings of the ozone concentration at certain points of the system. For example, an ozone mixing tank (baffle tank) will require a higher concentration of ozone than the external storage tank. Placing an ORP probe within the baffle tank and the external tank will allow you to effectively measure and adjust the concentration at both points.

Ozone Sizing – Conclusion

Properly sizing the ozone injection and dissolve rates is an important step in engineering any ozone application. To properly size the amount of ozone needed for a particular application ( as well as to maintain the optimal dissolve rate of the ozone) an experience is the key factor. However in the majority of cases the complexity of factors present will make it very difficult to precisely determine the concentration and quantity of ozone required. In such cases a pre-deployment pilot study may be required. Gathering feedback about parameters and factors affecting the effectiveness of the ozone treatment will make the full implementation of the ozonation technology more effective as well as reduce the overall operating costs by sizing the ozone injection skid properly.

If you require additional help and assistance in sizing a unit, please contact an Ozmotics representative at 1-877-386-3763 for a complimentary consultation and review of your application’s requirements.

Ozone is a very active form of oxygen. It is formed when the oxygen ( O2 ) molecules are broken down to oxygen atoms ( O). Oxygen atoms ( O ) in turn react with other oxygen molecules ( O2 ) to form ozone molecules (O3).

The simplified formula for the process is:

O2 + energy = 2 O1

2 O1 + 2 O2 + energy = 2 O3

Is ozone found in nature?

Ozone is indeed found in nature! In nature ozone is formed by lightning (largest source of naturally generated energy) and the oxygen in the air. In fact, ozone is considered to be mother nature’s air freshener as it’s that fresh smell that’s in the air after a thunder and lightning storm.

Ozone is also found in the upper stratosphere and is the main shield protecting the Earth from harmful UV radiation. Without ozone more UV radiation would reach the Earth’s surface causing the irreversible damage and harm to all living organisms exposed.

If ozone is that good for the environment why we don’t we breathe it rather than oxygen?

Ozone cannot be inhaled directly by humans, animals or any air breathing organism. The concentration of ozone that is found naturally in the lower atmosphere (where we live and breathe) is very small. Additionally, ozone is very unstable and it reverts quickly to oxygen by the reverse process through which ozone molecules were created. The ozone decomposition formula can be represented simplified as:

2 O3 = 3 O2

Is ozone technology a new technology?

Ozone has been used for centuries to treat drinking water. The first water treatment plant that used ozone to purify the water was built in Netherlands in 1893. Nice (France) was the first large city to use ozone to treat their drinking water. Los Angeles, California has the largest modern day water treatment facility using ozone technology to treat around 600 million gallons of water each day.

Where else is ozone used?

The applications of ozone span a variety of applications and industries.

Used as an alternative for chlorine and bromine in swimming pools, ozone is a very effective disinfectant, which even prevents the formation of chlorine and bromine byproducts.

For soil remediation, ozone has been used to clean up sites containing a variety of soil contaminants, including oil and fuel.

Ozone is an effective medium in controlling microbiological growth in cooling towers.

A major problem in cooling tower water treatment is legionella (legionnaires disease). In the prevention and control of legionella causing microbes, ozone has taken an eminent roll. The specific characteristics of the ozone disinfectant make sure it gets the job done where others fail.

Ozone injected to a cooling tower will also aid in the prevention of the formation of algae thus reducing fouling and increasing heat-transfer efficiency.

The benefits of ozone within the cooling tower applications are not only environmental in nature but are also helping reduce the cost of the operating and maintaining the cooling tower infrastructure therefore improving the overall bottom line.

Following is information about a few of the other applications and industries where introduction of the ozone is of great benefit:

- Aquaculture
- Agriculture
- Bottling
- Disinfection
- Electronics
- Farming
- Winery Sanitation
- Pharmaceutical
- Food Processing and Preservation
- Hydroponics
- Laundry
- Pools and Spas
- Hospitals
- Soil Remediation
- Wastewater Treatment

How is ozone generated?

To make the ozone in the large enough quantities and the high enough concentration to be useful for industrial and commercial processes the more efficient way of generating the ozone is required.

One of the most common and economical ways of generating large quantities of the industrial ozone supply is using a corona discharge (forcing the air through narrow gap in presence of high power energy field (corona discharge).

The process of ozone generation via the corona discharge can be described in two steps:

First, the feed air required to generate ozone must have the nitrogen and other trace elements removed since the air we breathe contains only about 21% oxygen and as much as 78% of nitrogen.

The oxygen concentrator removes nitrogen from the ambient air leaving almost pure oxygen to be feed to the ozone generator.

This process is by far more economical than using chemicals that need to be hauled from off-site and stored on-site until the time they are ready to be used. Ozone is generated on-site and on demand therefore eliminating the transportation and storage costs.

Since there is no residue (any residual ozone not used by the process will revert back to the more stable oxygen form without any additional requirement or intervention) ozone technology is very eco-friendly (creates virtually no pollution).

I need more information about using the ozone. Who I can contact?

If you require additional information about the ozone technology, engineering and design of the turn-key ozone injection skid or need help sizing a unit please contact your Ozmotics representative at 1-877-386-3763.

BTEX is a common acronym used to describe benzene, toluene ethyl benzene, and xylenes. BTEX compounds are some of the most commonly VOC (volatile organic compounds) found in petroleum derivatives such as gasoline and are often found as a persistent contaminants in the areas prone to gasoline and gasoline derivative spills (old gas stations, gasoline storage yards, refineries, etc.).

The inherent danger of BTEX is that toluene, ethyl benzene, and xylenes are very toxic substances with the documented history of harmful effects on the central nervous system. Because of the solubility of the majority of the BTEX components they are also prone to leaching into the underground waterways therefore polluting much wider area than the original contamination site. As such the decontamination of soils and ground water contaminated with the BTEX traces is strongly recommended.

Ozone is well known oxidizer able to decompose most of the complex organic substances to the less harmful basic elements from which the complex substance is derived. In case of the BTEX, this is the hydrogen and carbon. Through further reaction the hydrogen is used to create water and the carbon is either left in its pure state or further synthesized in carbon dioxide.

In-Situ soil and ground water remediation – Ozone Sparging.

In-situ ozonation of the BTEX contaminated soil and ground water has shown promising results in removing BTEX without the need to remove the contaminated soil for off-site remediation. Also referred to as “ozone sparging” the technology involves injecting the ozone deep inside the contaminated ground where it comes into the contact with the BTEX contaminants therefore starting the process of the decomposition.

In documented research studies and reviews of the data from projects where the ozone sparging has been successfully used for the soil and water remediation, the contamination of BTEX in the soil and surrounding ground water has been successfully reduced by as much as 90% within the first five weeks of the treatment and as much as 98% + reduced by the week seven or eight of the treatment.

Ozone for soil and ground water remediation – Conclusion.

Because the soil does not have to be removed or decontaminated off-site and because the ozone leaves virtually no byproduct traces (unlike chemical treatment), the in-situ ozone sparging is both an economical (saves money) and effective solution (98% or higher contaminant removal rate) for soil and ground water remediation of sites contaminated with the BTEX and other petroleum derivatives).

Therefore the in-situ ozone sparging is highly recommended in treatment of the BTEX and petrol derivative contaminated soil and ground water.

If you have an application that requires an ozone generator and need help sizing a unit please contact your Ozmotics representative at 1-877-386-3763.