Ozone in Wastewater Treatment

Some History

Ozone has been used in wastewater treatment for over 100 years.  Historically, its main use has been drinking water disinfection.   In Europe ozone treatment of drinking water is common.   In more recent years ozone has been used to treat wastewater for odor control and corrosion control.

Ozone Oxidation

Ozone is a naturally occurring form of atmospheric oxygen.   The oxygen we breath in has two atoms, Ozone has three.   The third atom of oxygen makes the ozone molecule highly unstable and highly reactive with a very high oxidation potential.

Other oxidants such as hydrogen peroxide, sodium hypochlorite (bleach) and paracetic acid have a high oxidation potential as well and are commercially available.  The typical oxidation process destroys organic compounds and odor causing chemicals that may be present in wastewater by converting the unwanted organic molecules to carbon dioxide and water.   Or in the case of the odor causing molecule hydrogen sulfide, it will convert it to oder less sulfides and sulfates.

Lowering COD

Ozone has been successfully used to remove odor, suspended solids and to lower chemical oxygen demand (COD).

Ozone Sustainability

Because of its extreme instability, ozone will only last around 10 minutes in pure water and less than 10 seconds in wastewater.   This is because of the high amount potential reactants present in wastewater.

Ozone Generators

Also, because of its extreme instability, ozone must be generated at the point of use.   Typical ozone generators such as a Corona Discharge device will use atmospheric oxygen from the air, that when passed through the electrical discharge will generate ozone.   Typical generation rate is around 1 to 9% by weight ozone.   Ozone generators are sized by weight of Ozone produced per given amount of time, minutes or hours.