No preliminary contact or sedimentation chambers are necessary for which oxidation process?

• A. aeration with oxygen
• B. potassium permanganate oxidation
• C. manganese greensand filters
• D. ozone oxidation

Answer: (D)

Ozone oxidation is efficient and fast enough that the oxidation happens during a single dedicated ozone contact stage. The ozone contactor provides both the dissolution and the necessary contact time in one unit, so there isn’t a need for an extra preliminary contact tank or a sedimentation basin to allow the reaction to occur. After treatment in that contactor, the water can move directly to downstream steps.

In contrast, potassium permanganate oxidation typically requires adequate mixing and a defined contact time before clarification, and manganese greensand relies on contact within the filter media itself. Aeration with oxygen is mainly a gas-transfer process and doesn’t depend on a prior settling stage for the oxidation step.