Colored water is unpleasant and responsible for many of the complaints expressed by water utility customers. Poor aesthetic qualities of drinking water often cause customers to seek alternative water sources. Water appears to be colored when dissolved matter absorbs visible light or when suspended particles scatter light. Most molecules responsible for colored water contain one to several aromatic rings, which can be difficult and costly to remove. Conventional treatment techniques (i.e. coagulation — flocculation/sedimentation — filtration) reduce the amount of color in drinking waters; however, highly colored waters require additional treatment steps to effectively remove the remaining color-producing compounds. Granular activated carbon (GAC) adsorption can be used for advanced color removal, but GAC has a short lifespan, requires frequent backwashing and can be expensive.

Ozone offers an efficient and environmentally-friendly color removal alternative. Color in waters produced from organic compounds and their metabolites can break down rapidly when in contact with ozone. The required CT values (concentration x contact time) for oxidation with ozone are generally an order of magnitude lower those of chlorine, chlorine dioxide, hypochlorite, etc. Ozone is the most powerful oxidant commercially available, capable of breaking both C=C and N=N double bonds that are found within color-producing compounds. The powerful oxidation potential of ozone has made color removal in drinking water one of the most common ozone applications.

The need for advanced color removal is not limited to drinking water treatment, having crossed over to both industrial and municipal wastewater treatment. Ozone is widely being used across various industries to remove color from effluents. Industries that have implemented ozone in their processes include dye manufacturers, textile mills, and pharmaceutical factories. Ozone is also used as a bleach in many processes, such as pulp and paper manufacturing, and kaolin production.

Degremont Technologies — Ozonia has a broad range of products from laboratory-scale ozone generators to large engineered ozone plants to satisfy any possible color removal application. In order to simplify the integration of ozone into existing or future processes, Degemont Technologies — Ozonia has engineered and fabricated a broad range of ozone generators and ozone generation systems to fit nearly every application.

For more information on color removal or other ozone or UV related topics, contact your nearest Ozonia office or agent through our website.