Ozone (03) is a powerful oxidant, and application to effluent treatment has developed slowly because of relatively high capital and energy costs compared to chlorine. Energy requirements for ozone are in the range of 10 to 13 kWh/lb generated from air, 4 kWh/lb from oxygen, and 5.5 kWh/lb from oxygen-recycling systems. Operating costs for air systems are essentially the electric power costs; for oxygen systems the cost of oxygen (2 to 30/lb) must be added to the electrical cost. Capital costs of large integrated ozone systems are $300 to $400 a pound per day of ozone generated and $100 a pound per day of ozone for the generator alone. Actual uses of ozone include odor control, industrial chemicals synthesis, industrial water and wastewater treatment, and drinking water. Lesser applications appear in fields of combustion and propulsion, foods and pharmaceuticals, flue gas-sulfur removal, and mineral and metal refining. Potential markets include pulp and paper bleaching, power plant cooling water, and municipal wastewater treatment. The odor control market is the largest and much of this market is in sewage treatment plants. Use of ozone for odor control is comparatively simple and efficient. The application is for preservation of environmental quality; in addition, alternative treatment schemes requiring either liquid chemical oxidants (like permanganate or hydrogen perioxide) or incineration can significantly increase capital and costs.
Ozone applications in the United States for drinking water are far fewer than in Europe. However, the potential market is large, if environmental or health needs ever conclude that an alternate disinfectant to chlorine should be required. Although energy costs of ozonation are higher than those for chlorination, they may be comparable to combined costs of chlorination dechlorination-reaeration, which is a more equivalent technique. One of ozone's greatest potential uses is for municipal wastewater disinfection.
Technical, economic, and environmental advantages exist for ozone bleaching of pulp in the paper industry as an alternate to hypochlorite or chlorine bleaching which yields deleterious compounds to the environment.
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