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.

Benefits of Ozonation in Industrial Cleaning Applications

The typical Clean in Place process consists of injecting water, heat and a combination of chemicals to clean the inacessable surface areas such as pipes, valves, pumps, etc., all of which are difficult to clean with conventional methods.

Most of CIP processes involve the application of heat as well as multiple water flushings with or without the use of chemical agents to aid in cleaning process. The CIP process although simpler than manually disassembling the infrastructure, still requires considerable use of energy and resources. CIP also requires considerable production down-time in order to elevate the temperature of the surfaces to be cleaned and then cool down back to the original working temperature (source: International Ozone Association, Clean in Place publication http://www.Io3a.org).

Unlike conventional methods used for the CIP process, the use of ozone for the CIP process requires no elevation in the surface temperature of the equipment to be cleaned (pipes, pumps, valves, etc.) as ozone is most effective at lower temperatures. As such the warm-up and cool-down times typically associated with the conventional CIP processes and techniques are greatly reduced.

The second benefit of using ozone in industrial cleaning applications is the fact that ozone is effective for the remediation of both biological as well as non-biological contamination. Ozone is a well-known and proven oxidizing agent that will destroy even the hardiest microbiological organisms as well as can oxidize the majority of organic components.

In addition to its universal application, ozone wil leave no residue or chemical traces after the cleaning process is completed therefore making it a safe medium for the remediation and decontamination of the CIP surfaces used in the food industry (i.e. wineries, breweries, food processing etc.). Because of its short half-life cycle and its tendency to quickly revert to oxygen, ozone will typically leave the clean surface free of trace contamination therefore requiring less rinsing compared to other CIP processes.

Effectiveness of Ozone in the Inactivation of Microbiological Organisms

Ozone is very effective in inactivating the majority of biological micro organisms that it comes in contact with. It would appear that ozone will rupture the inner cell membrane of the microbiological organism it reacts with therefore destroying or incapacitating the affected organism. For viruses and other multi-cell micro organisms (that are less affected by the inner membrane rupture) ozone is still an effective destruct medium. Ozone will diffuse through the protein coat into the nucleic acid core, resulting in damaging the viral RNA or oxidizing the outer shell of the viral organism therefore affecting the DNA and RNA structure of the viral organism (source: Ozone Inactivation of Microorganisms: Kinetics and Mechanisms, Ahmed Yousef, Professor of Food Microbiology Ohio State University, Ozone-V Conference April 2, 2007,Fresno California).

Effectiveness of Ozone in Oxidizing Organic Compound Contaminants

Ozone is a strong oxidant with the oxidation potential exceeding that of chlorine and other strong oxidants. As such, ozone will react with most of the complex organic compounds reducing them to simpler elemental compounds that are easy to flush out of the infrastructure being sanitized.

For example, most of BTEX compounds will be oxidized to carbon dioxide (CO2) and water (H2O) both being safe to release into the environment and neither being considered as a dangerous contaminant byproduct in the CIP process. As such, ozone is a choice reactant for in-situ treatment and remediation of the areas affected by the BTEX (in situ ozone sparging: http://www.ozmoticsinsider.com/2008/10/ozone-for-soil-and-ground-water-remediation-in-situ-ozone-sparging/ ).

In addition to soil and ground water remediation for BTEX contamination, ozone can be effectively used to decontaminate and remediate the inner surfaces of equipment and infrastructure (i.e. cleaning of the petroleum storage tanks, pipes, pumps,etc.).

Besides hydrocarbon derivatives, ozone can be used to aid in the CIP procedure for most of the organic compound contaminated infrastructure elements. And since most of the residual and unused ozone will revert back to oxygen during or shortly after the treatment has finished, ozone can be used both as a stand alone CIP agent or it can be used in combination with other chemicals or treatment procedures (such as a pre-wash).

Ozone for Clean in Place Applications – Conclusion

Ozone is very effective for Clean in Place and other industrial infrastructure and equipment decontamination and remediation procedures. The energy and water savings achieved by introducing ozone as an active cleaning agent for the CIP procedure, are well documented. And since ozone generation technology can easily be scaled to fit any application (ozone is generated on-site from ambient air so the only requirement for using the ozone generator on site is the availability of electrical power), ozonation technology for the CIP application can be made quite portable.

If you are interested in learning more about the integration of ozone for Cleaning in Place (CIP) applications or need help sizing a unit please contact an Ozmotics representative at 1-877-386-3763.