Ozone Applications
Ozone cannot be stored; therefore, it must be generated on-site and dissolved into water on-site at the rate of consumption.
Ozone is generated as a gas that must be dissolved into water. A mixing device will be necessary for ozone gas to dissolve into water efficiently. There are many variables to consider when determining the proper mixing device for a given application.
The information provided below serves to provide a better understanding of the variables that may affect your application. Dissolving ozone into water for any of the various applications listed above may be very simple or could be extremely complicated. This will be depending upon the application and the variables working within that application.
Porous Diffusers
Bubble diffusion is the oldest and simplest method for dissolving ozone into water. This is essentially a porous device used for breaking the gas into small bubbles at the bottom of a water column to allow the bubbles to slowly rise to the top of the column and dissolve into water.
The pore size of the diffuser will affect the size of the gas bubbles that are created with the bubble diffuser. Two smaller bubbles will have greater surface area than one bubble of the same gas volume. Greater surface area will achieve improved contact with the gas bubble and water, therefore increasing the rate of mass transfer of ozone into water. It is important when choosing a bubble diffuser to find the smallest pore size possible.
Water column height
The height of the water column that ozone is bubbled into will affect the mass transfer efficiency greatly. The diffuser should be placed at the bottom of the column, this way, the gas bubble must travel the greatest distance within the water column prior to escaping into the head space.
Taller columns will lengthen the time duration that the bubble is in contact with the water and can dissolve into the water. More importantly, taller columns will create a higher pressure at the bottom of the column. This high pressure will exert greater force on the surface of the bubble and force more gas into solution.
Ozone Injection
Ozone can be injected upstream of the static mixer using a tee or any other device to force ozone gas into the water stream. Then, the static mixer can be used to break up the gas into small fine bubbles to dissolve into water efficiently.
Essentially a static mixer can be used in place of a venturi injector, this can be helpful when energy savings are desired due to the lack of necessary pressure differential.
To force ozone gas into the water stream the ozone gas must be at a higher pressure than the water stream, is necessary to achieve gas flow into the water stream.
This may eliminate the option of using only a static mixer and may require using a venturi injector to inject the ozone into water. The option of placing a static mixer in-line after the venturi is also an option.
A static mixer can be placed anywhere in a piping system intended to mix ozone gas with water. The best location when using a venturi injector to infuse ozone with the water is a few feet downstream of the injector. If using a contact tank or off-gassing column place the static mixer directly at the inlet of the tank with the venturi a few feet (as far as practical) upstream from the static mixer.
Sidestream Injection
A venturi injector is a very common method of ozone injection in industrial applications. A venturi injector combines a method for ozone injection and provides good mass transfer efficiency in one device.
A venturi injector requires a pressure differential across the device to create a vacuum to pull ozone gas into the device. Then, using mixing vanes the gas is thoroughly mixed with the water.
A venturi injector creates very small bubbles desired for great mass transfer and a violent mixing action to dissolve gas into water. Using a venturi injector alone may achieve mass transfer rates of 90%.
For a venturi injector to work properly there must be a pressure differential between the inlet and outlet of the device. This usually requires a separate water pump to increase the water pressure at the inlet of the venturi injector. It is then important that the outlet of the venturi injector is not obstructed or impeded in any way.
We suggest placing pressure gauges directly at the inlet and outlet of the venturi injector. This will help with troubleshooting and determine the effectiveness of the device.
Inlet pipe with radial difuser
Sidestream Injection with Static Mixer
Static mixers are any static device designed for the sole purpose of mixing two flows together. In our application we are mixing ozone gas with water, therefore the same principle of breaking the bubbles up into the smallest possible bubbles is the goal with the mixer.
Sizing a Static Mixer
A static mixer is sized based on the velocity of water through the mixer. Each static mixer has vanes or mixing devices inside that require a specific velocity of water past those devices to achieve the desired results. This sizing will translate to water flow rate for our purposes. Each mixer should be sold and marketed with a range of flow rates that the mixer will work well with.
Ozone Generator and accessories equipment
Ozonation System for small production capacities
Ozonation System for large production capacities on low effluent flow rates
Ozonation System for large production capacities on low / medium effluent flow rates
Ozonation System for large production capacities on high effluent flow rates
Typical flow sheet of an ozonation system for industrial wastewater applications
Off Gas System
Using a venturi injector will require a method of removing the undissolved oxygen and ozone from the water.
Unlike the bubble diffuser where the bubbles will naturally rise to the headspace and escape the piping system, a venturi injector has no method of removing this undissolved gas, one must be provided.
A contact tank is a popular method, there are also de-gas chambers and columns that can be used. Ozone compatible air vents are used to remove this gas and vent to a safe location or to an ozone destruct unit.
If an off-gas system is not used, the excess gas bubbles that may carry residual ozone can off-gas in undesirable locations causing safety concerns. Also, this excess gas may volatilize some of the dissolved ozone back into the gaseous form.
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What is Ozone?Ozone is formed naturally when energy from ultraviolet (UV) light or electrical discharge forms single oxygen atoms that combines with (O2) molecules to form ozone. Ozone (O3) is created naturally in the stratosphere by short wavelength ultraviolet radiation, in thunderstorms, ozone forms due to a high voltage lightning strike. The fresh scent after a thunderstorm is caused by ozone formation. For commercial and industrial uses, ozone is mostly produced using high voltage electrical corona discharge.
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How is Ozone created?Ozone is formed naturally when energy from ultraviolet (UV) light or electrical discharge forms single oxygen atoms that combines with (O2) molecules to form ozone. Ozone (O3) is created naturally in the stratosphere by short wavelength ultraviolet radiation, in thunderstorms, ozone forms due to a high voltage lightning strike. The fresh scent after a thunderstorm is caused by ozone formation. For commercial and industrial uses, ozone is mostly produced using high voltage electrical corona discharge.
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How is Ozone an effective oxidisation substance?O3, Ozone is an unstable molecule under ambient conditions due to the weak bonds holding the third oxygen atom. This instability makes ozone a great, natural potent, oxidizing agent. Oxidisation occurs when the ozone meets oxidizable substances like microorganisms (bacteria, viruses, moulds, and parasites) and other organic and inorganic compounds like metal irons, plastics and rubbers. This causes the third oxygen atom to be released from the ozone molecule (O2) is left.
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Is Ozone environmentally safe?Ozone quickly and naturally decomposes to oxygen and with no other byproducts. Ozone in environmentally friendly and sustainably generated onsite. Without the need for storage containers and shipping, ozone systems have significantly smaller carbon footprints than alternatives.
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What is oxidisation?Oxidation is the chemical interaction of oxygen-containing molecules with substances they encounter. Oxidisation produces chemical changes characterised by the loss of electrons. In ozone oxidisation reactions, the unstable third oxygen atom is released from the ozone molecule to the molecule being oxidised. In disinfection, the transfer of energy via oxidation results in the rupture or lysing of the outer membranes of the microorganisms. As ozone molecules enter the lysed microorganism, genetic material is destroyed. For the treatment of metal-containing substances, oxidation by ozone typically hydrolyses, inorganic molecules, causing them to become insoluble.
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How is Ozone used?Ozone is often used as an anti-microbial agent. Ozone is very effective at oxidising and destroying organic and other compounds. Here are some typical applications of where ozone is used: Municipal water treatment Municipal and industrial wastewater treatment Bottle washing Cleaning in place (CIP) Surface washdown and sanitation Odour control Cooling towers Ultra Pure Water Paper industry