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Ozone Dissolution

Ozone – many uses, many benefits – made cost efficient with better mass transfer

As one of the best oxidants that doesn’t leave a chemical residual, ozone has many uses in water dependent industries. From drinking water to wastewater, marine and ballast water, pulp and paper bleaching and treatment to pharmaceuticals, ozone provides excellent treatment.

As a disinfectant for drinking water supplies, it does not produce the disinfection by-products associated with chlorine. In addition, ozone breaks down precursors of disinfection by-products (DBPs), lowering chlorine demand and preventing DBP formation with chlorine residuals in distribution lines. Ozone is also effective in breaking down chemicals that cause taste and odor complaints.

Because ozone is generated on site and is used immediately, it does not require transport or storage, making it an excellent disinfectant for space constrained applications. It has many uses in the marine industry, from disinfection of drinking water supplies, boiler feed water treatment, and ballast water treatment. In the pulp and paper industry, ozone bleaching improves production, providing exceptional brightness and superior pulp strength with reduced chemical and energy costs. On the wastewater side, ozone can break down (cracking) complex COD from paper processing, making them biodegradable, as well as breaking down color components to help meet regulatory compliance requirements.

In the pharmaceutical industry, ozone disinfects without leaving chemical residuals or forming harmful byproducts. It also breaks down pharmaceutical residuals (APIs and EDCs) and personal care products (PCPs), to protect the environment and downstream drinking water supplies. In mining, it can oxidize difficult compounds like cyanide, making them easier to remove from waste streams.

Dissolution in water is complex

Due to the highly reactive nature of ozone, its solubility in water is not predictable by Henry’s law alone. Ozone concentration and pressure in the feed stream are key factors. Using an oxygen feed vs. an air feed into the ozone generator produces a higher ozone concentration and pressure in the feed stream. Other factors affecting solubility are temperature and pH, with solubility increasing as temperature and pH decrease. In addition, excess UV light increases ozone solubility.

Of course, all mass transfer between phases (gas and water) improves with proper mixing. Proper ozone application may use a number of advanced mixing methods such as venturis, static mixers, sidestream injection, and plug flow reactors. In the wastewater industry, advanced ceramic fine bubble diffusers transfer ozone in suspended growth systems.

Better mixing methods produce better ozone dissolution, reducing reaction time and enhancing ozone efficiency resulting in a lower applied dose. Better mixing improves the hydraulic efficiency of ozone contactors.