Ozone, color removal processes

The foremost authorities on hygiene in that country, among whom were the late Professors Roux and Calmette of the Pasteur Institute, have never ceased to consider the treatment of water with ozone to be the best disinfecting process known. It does not add to the water any injurious foreign substance. Moreover, ozone never generates unpleasant tastes, as chlorine and its derivatives do on the contrary, it can destroy most unpleasant tastes and odors. Color due to organic decomposition products in water can also be removed. 

In water and wastewater treatment ozone is used for the following purposes 1) disinfection 2) oxidation of organic compounds, including removal of taste, odor, and color and 3) oxidation of inorganic com-pounds.f Ozone is usually used as pre-, intermediate-, or posttreatment with other processes such as sedimentation, adsorption, filtration, etc. 

Peracetic acid (Steiner N, 1995, Evaluation of peracetic acid as an environmentally friendly alternative for hypochorite . Textile Chemist Colorist 27 (8), pp. 29-32) as well as a waterless bleaching system that uses oxygen gas (Mowbray J 2008, Light fantastic , Ecotextile News No. 17 Aug/ Sep, pp. 22-24) have been reported as alternate and enviromnent-friendly methods for bleaching cotton. Ozone also can be used as another waterless process to bleach cotton. Bleaching removes residual impiuities and changes the natural color of cotton fabric to clear white rather than the off-white (i.e. various shades of yellow). 

As an oxidant, ozone removes iron, odors, and sometimes color, from water. It is used to oxidize organic substances in water, so they can he more easily removed in subsequent processes, i.e., coagulation, sedimentation, and filtration. Occasionally, ozone is combined with peroxide to increase its oxidation potential (peroxone). Peroxone can remove a wide variety of organic contaminants. 

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