Downloaded By: [BOSE - Ozone: Science & Engineering] At: 09:21 4 June 2008 Ozone: Science and Engineering, 30: 202–209 Copyright # 2008 International Ozone Association ISSN: 0191-9512 print / 1547-6545 online DOI: 10.1080/01919510801942265 Experimental Results of a Cost-Effective Ozone Generator for Water Treatment in Colombia Diego Fernando Echeverry Ibarra, 1 He ´ ctor Cadavid Ramı ´rez, 1 Jose ´ Marcos Alonso, 2 Guillermo Aponte Mayor, 1 and Alberto Ga ´ lvis Castan ˜o 1 1 Faculty of Engineering-Universidad del Valle, Cali, Colombia 2 Electrical Engineering Department, Universidad de Oviedo, Gijo ´n, Spain Obtaining high-quality cost-effective water, minimizing the public health risk generated by pathogenic elements or disinfection sub-products such as trihalomethane and/or chlorophenol, has made necessary the use of technologies different to chlorination. In this paper, we present the implementation of a high-voltage, high-frequency flyback inverter to generate ozone, and outline the main character- istics and uses of a prototype of water ozonation from a well for a hospital in Colombia. With the prototype, the ozone dose can be adjusted through the duty cycle modulation; switching was done with a Mosfet and the voltage signal was increased with a ferrite technology transformer. The source is characterized by its simplicity, good performance and low cost. Keywords Ozone, Ozone Generation, Flyback Inverter, Water Ozonation, High Frequency, High Voltage INTRODUCTION Ozone properties have been studied since the beginning of the 20th century. Ozone is classified as the second most powerful disinfectant in the world. Ozone can be consid- ered an effective and safer alternative in solving problems associated with chlorination, such as the formation of tri- halometane and/or chlorophenol, which emerge when chlorine reacts with organic matter dissolved in water (Rice, 1980) and are considered to generate a chronic risk due to their carcinogenic effect. Thanks to the character- istics of ozone, ozonation equipment is used widely and effectively in drinking water treatment (EPA, 1999; Galvis et al., 2004, 2005), in waste water treatment, in environ- mental treatments, in the manufacturing of semiconductors and in various industry sectors (Echeverry and Aponte, 2003; Loeb, 2002). Due to the importance of ozone use in water disinfec- tion, it is necessary to design and build cost-effective ozone generation equipment. Nowadays, there have been significant advances in reducing the size of the equipment and increasing efficiency, which favors the feasibility of ozone applications in many fields. However, this kind of equipment is still expensive com- pared with chlorination systems equipment. The dielectric barrier discharge (DBD) is the best method found until now to generate ozone (Kogelschatz, 2003). In order to obtain ozone through the DBD dis- charge, which is considered as a partial discharge in a gas, it is necessary to have an arrangement of electrodes separated by a dielectric material that allows managing intense electric fields that provide the necessary energy to dissociate oxygen molecules. This arrangement of electro- des is known as a discharge cell. When ozone is formed, it has a high quantity of energy which makes it a very unstable substance. This facilitates many applications but also requires it to be generated in the place where its use is needed. Some of the alternatives to reduce the costs of ozone generation equipment are: 1. Reducing the power consumption per unit of ozone generated (gr-O 3 /kW-h). 2. Designing cells that require less cooling. 3. Reducing the size of the cells and/or the high- voltage transformer. 4. Developing more efficient and cost-effective electric sources. These alternatives can be achieved through the high- frequency dielectric barrier discharge ozone generation Received 12/7/2006; Accepted 1/18/2008 Address correspondence to Jose´ Marcos Alonso, Universidad de Oviedo, Electrical Eng. Dept., Campus de Viesques S/N, Edificio 3, Room 3.2.20, 33204-Gijo´n, Asturias, Spain. E-mail: marcos@uniovi.es 202 D.F. Echeverry Ibarra May–June 2008