Electrolytic Ozone Generation and Its Application in Pure Water Systems

Controlling Microbial Contamination

Irrespective of how well a plant has been designed and constructed, when no special measures have been taken, it's virtually impossible to avoid microbial contamination in a pure water network. This is especially the case when a system isn't continually replenished with fresh makeup water such as overnight or over the weekend when production is shut down and the water stands in a tank or circulates in a closed loop.

Only for specific applications do regulatory bodies require certain criteria are met and request operators of such plants to carry out validation tests. In all other cases, operators are left to their own means and follow accepted guidelines to establish and maintain the integrity of their pure water systems.

Methods

• Shock Disinfection (with chemicals such as peroxide or hypochlorites)
• Shock Sterilization with Steam
• UV Irradiation
• Sterile Filtration

Microbial growth as a function of ozone concentration

Basic electrolytic ozone generator cell

The main advantages of producing ozone with an electrolytic system are:

• There is no ionic contamination because the feed water is being dissociated using a solid hydrated ion exchange membrane.
• The process water being disinfected is the source of oxygen for the generation of ozone-consequently, no outside contamination is introduced into the system being treated.
• The ozone is dissolved in the process water as soon as it is formed, resulting in ozonation with minimal equipment.
• By operating the cell under pressure, relatively high ozone concentrations can be produced.

Ozone generator installation

For all applications, it was found best to install the ozone generation system in the loop and return just before it re-enters the storage tank. The by-pass flow for the electrolytic system is tapped off before the loop's pressure retaining valve and reintroduced on the low pressure side