Ozone, water treatment

Koseki, S. and Isobe, S. (2006). Effect of ozonated water treatment on microbial control and on browning of iceberg lettuce (Lactuca sativa L.).. Food Prot. 69,154-160. 

F ranee, the birthplace of ozone water treatment, is the only country in Europe to remain faithful through half a century to the idea of using ozone to purify drinking water. 

Up to now, ozonation of drinking water has been considered too difficult, especially in comparison with chlorination. The outlay for the relatively expensive installations and the high costs of operation were objectionable. In most cases the plants have seemed unprofitable. It appears, moreover, that all the European ozonation plants still employ water-treatment processes which do not permit proper utilization of all the ozone produced by the ozonators. Perhaps 40% of the ozone is lost because of the difficulty of dissolving the gas in the water with the available means. On the other hand, there is no doubt of the actual efficacy of the ozone water treatment in the French plants in operation. 

Today in addition to Paris, many other cities use ozone in production of potable water. Zurich, Switzerland, Florence, Italy, Brussels, Belgium, Marseille, France, Singapore and Moscow, Russia all have ozone water treatment plants. In Europe many swimming pools, both public and private use ozone in place of chlorine. With ozone, no salts are added to the water, so that in addition to a high level of sterility, the acidity (pH) is easier to control. In the United States, ozone s use is limited, but LaSalle, Illinois has a relatively new ozone water treatment facility. ... 

Figure 8.2 A Combined Oxygen - Ozone Water Treatment Plant...

FIGURE 8.2 COMBINED OXYGEN - OZONE WATER TREATMENT PLANT.163... 

Heng S, Yeung KL, Djafer M, and Schrotter JC. A novel membrane reactor for ozone water treatment. J. Membr. Sci. 2007 289 67-75. 

Heng S, Yeung K-L, Julbe A, Ayral A, Schrotter J-C. Preparation of composite zeolite membrane separator/con-tactor for ozone water treatment. Micropor Mesopor Mater 2008 115 137-146. 

Ozone is sometimes used as a disinfectant in place of chlorine, particularly in Europe. Figure 13.10 shows the main components of an ozone water treatment system. Basically, air is filtered, cooled, dried, and pressurized, then subjected to an electrical discharge of approximately 20,000 volts. The ozone produced is then pumped into a contact chamber, where water contacts the ozone for 10-15 minutes. 

Figure 13.10 A schematic diagram of a typical ozone water-treatment system.

Ozone has been used eontinuously for nearly 90 years in municipal water treatment and the disinfeetion of water supplies. This praetiee began in Franee, then extended to Germany, Holland, Switzerland, and other European countries, and in reeent years to Canada. Ozone is a strong oxidizing substance with baetericidal properties similar to those of ehlorine. In test conditions it was shown that the destruetion of baeteria was between 600 and 3,000 times more rapid by ozone than by ehlorine. Further, the baeterieidal aetion of ozone is relatively unaffeeted by ehanges in pH while ehlorine effieaey is strongly dependent on the pH of the water. 

Figure 9 shows the details of a typical horizontal tube-type ozone generator. This unit is preferred for larger systems. Water-cooled plate units are often used in smaller operations. However, these require considerably more floor space per unit of output than the tube-type units. The air-cooled Lowther plate type is a relatively new design. It has the potential for simplifying the use of ozone-generating equipment. However, it has had only limited operating experience in water treatment facilities. 

Seek alternatives to chlorine for water treatment and disinfecting applications. For example, sodium hypochlorite has been used both in industrial and municipal water treatment applications (Somerville, 1990). Other alternatives include calcium hypochlorite, ozone, ultraviolet radiation and heat treatment (Negron, 1994 Mizerek, 1996). 

The use of ozone for water treatment is now well established and has the follow ing advantages ... 

Figure 13.3 A large ozone generator for water treatment producing 60kgh . (Courtesy Ozonia Ltd.)...

Effective removal of the estrogens 17 3-estradiol, estrone, and 17a-ethynylestradiol has been achieved using ozone under conditions that simulated those used for water treatment (Deborde et al. 2005). Analysis of the products showed the occurrence of two reactions ... 

Acero JL, K Stemmier, U van Gunten (2000) Degradation kinetics of atrazine and its degradation products with ozone and OH radicals a predictive tool for drinking water treatment. Environ Sci Technol 34 591-597. 

Industrial wastewater, oxygen demand and organic carbon in, 25 887t Industrial wastewater flow, 25 885 Industrial wastewater pollution control, ozone use in, 17 808-809 Industrial wastewater treatment. See also Industrial water treatment activated carbon application, 4 752-753 and bioremediation, 3 755 Industrial water treatment, 26 125-150 biofouling in, 26 146-149... 

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