What is the best method to dissolve ozone in water?

ozone drinking water

What is the best method to dissolve ozone in water? A contact tank or direct injection system?

Both contact tanks and direct injection systems can provide stable dissolved ozone in water, but the choice depends on the specific requirements and constraints of the application. Let’s explore both methods:

Contact Tank:

A contact tank, also known as a retention tank or ozone contactor, is a separate vessel where ozone and water are brought together and allowed to interact for a certain period. The ozone is injected into the tank, and the water remains in the tank for a predetermined contact time to achieve sufficient to dissolve ozone.


  • Contact time: A contact tank allows for extended contact time between ozone and water, promoting thorough ozone dissolution and reactions. This is beneficial for applications that require longer contact times to achieve desired disinfection or oxidation levels.
  • Stability: Contact tanks generally provide a more stable dissolved ozone concentration since the ozone is given ample time to dissolve and equilibrate in the water. This stability can be advantageous for applications where consistent and reliable ozone levels are crucial.


  • Footprint: Contact tanks require additional space and infrastructure, as they are separate vessels that need to be integrated into the water treatment system.
  • Time Delay: The contact time required in a contact tank introduces a delay in the ozone treatment process. This delay can be a limitation for applications that demand immediate or continuous ozone treatment.
Ozone Water Contact Tank
Water Injection skid

Direct Injection System:

In a direct injection system, ozone is injected directly into the water stream at the point of application, such as a pipe or a mixing chamber. The ozone gas is rapidly dissolved into the water as it passes through the system.


  • Compact Design: Direct injection systems are often more compact and can be easily integrated into existing water treatment processes. They require less space compared to contact tanks.
  • Immediate Treatment: Since ozone is injected directly into the water stream, there is no delay in the treatment process. Immediate ozone dissolution occurs, allowing for rapid disinfection or oxidation.
  • Flexibility: Direct injection systems offer flexibility in ozone dosage control, allowing for adjustments based on varying water flow rates or ozone demand.


  • Contact Time Limitation: Direct injection systems may have limited contact time between ozone and water, depending on the flow rate and design of the system. This can affect the efficiency of ozone dissolution and reactions, especially in applications that require longer contact times.

In summary, contact tanks provide longer contact times and greater stability in dissolved ozone concentration, making them suitable for applications that prioritize extended treatment duration and consistent ozone levels. Direct injection systems are more compact, provide immediate treatment, and offer flexibility in ozone dosage control, making them suitable for applications that require rapid response or variable ozone dosing. The choice between the two methods depends on the specific needs, constraints, and treatment goals of the water treatment application.

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