Ozone (O3) is a natural component of the earth's upper atmosphere and it always exists in the gaseous form at ambient conditions. The three atoms of oxygen that make up one molecule of ozone are nearly the shape of an equilateral triangle. Ozone is the most powerful known oxidizing agent that can be used on a practical scale for water treatment applications. Disinfection is considered to be the primary mechanism for the inactivation/destruction of pathogenic organisms to prevent the spread of waterborne diseases to downstream users and the environment. It is important that wastewater is adequately treated prior to disinfection in order for any disinfectant to be effective.
Decoloration can be another use of Ozone. It is very efficient to eliminate color due the nature of many dyes (double bonds, chromophor groups, etc.).
- The necessary retention time for decoloration usually does not exceed more then 30 minutes. This results in small reaction volumes.
- Color reduction > 90%
- Bacterial reduction > 99%
- Pilot plant available for test
How does it work?
When ozone decomposes in water, the free radicals hydrogen peroxy (HO2) and hydroxyl (OH) that are formed have great oxidizing capacity and play an active role in the disinfection and decoloration process. It is generally believed that the bacteria is destroyed because of protoplasmic oxidation resulting in cell wall disintegration (cell lysis). The effectiveness of disinfection depends on the susceptibility of the target organisms, the contact time, and the concentration of the ozone. On the other hand, the design of decoloration systems with ozone depends mainly on the color causing compounds and on the COD background load in the water.