Ozonation is a fast, reliable and proven way of water disinfection, i.e. removing (killing) microorganisms: bacteria and viruses. Water ozonation process removes all its flavours, odours and discolouration. In the ozonation process, no harmful post-reaction products (by-products) are produced. The environmental friendliness derivative is a great advantage of the process.
The use of ozone for water treatment has already a century-old tradition. The first industrial water ozonation installation was installed in the Netherlands in 1893 and then the number of such installations rapidly increased until World War I. Then cheap methods of obtaining chlorine gas were developed. Cheap chlorine has stopped the development of technology for drinking water disinfection with ozone. Only after World War II that the return to the ozonation of drinking water is reported. Ozone in water treatment technology is used to:
- improve organoleptic properties of water (colour, flavour),
- remove bacteria and viruses,
- oxidise natural organic matter,
- oxidise micropollution
- oxidise some metals (Fe and Mn),
- increase in biodegradability of organic matter before filtration by biologically active carbon filters.
The process of ozone solubility in water is described by Henry isotherm. The quantity of ozone dissolved in water will therefore depend on the gas phase pressure, the ozone content, but also on the temperature and pH of water. Ozone is subject to spontaneous decomposition in water and its rate depends on pH and temperature as well as water composition. Ozone solubility in water is relatively high when compared to the solubility of oxygen or nitrogen.
Water ozonation is also applied to obtain a cheap disinfectant. Washing meat (poultry carcasses, pork, horse and beef half-carcasses), vegetables, fish slices as well as washing tools, floors in food processing plants is a recent standard. Ozonated water is also used for decontamination of food tanks (e.g. for milk), egg washing, ozone ice production. Water is an excellent ozone solvent and easily available. Ozone produced in-situ is dissolved in water using Venturi tubes, ozone mats, bubbler systems. Our company produces industrial ozone generators and also supplies complete lines for production of ozonated water i.e. water ozonation systems. After using ozone in this process, the level of its residue is 0.1 ÷ 0.2 mg/L – it is a concentration decreasing over time and completely safe for human, even in case of consumption of such water. High installation costs are opposed to very low operating costs, pointing clearly to the economic relevance of using ozone as a safe and environmentally friendly (ozone is decomposed into oxygen) disinfectant.
Industrial ozone generators for water treatment:
Water ozonation – graphs and technical specification:
Water ozonation – conclusion
Cold water with neutral reaction is the best for ozone. The higher ozone concentration, the longer half-life. The practical half-life of ozone, as I mentioned in the water at 20° C and pH, 7 is about 30 minutes. As usual, in addition to the given parameters that can be entered into the equations, the geometry of the tank, uneven walls, presence of hard radiation, pollution (very important) present in water have an influence on the half-life. So if we want to use ozonated water, we must produce it on an ongoing basis. The bubblers should be made of sintered glass, chrome-plated or acid-resistant steel. (Ozone resistant) mats produced especially for this purpose can be used. Water ozonation with Venturi tube is used in large industrial installations. Determining the parameters of the supply and exhaust gas from the ozone generator is necessary. This is required by the design of the Venturi tube. Our company provides professional Venturi tubes and offers payable scientific and technical support for such water ozonation systems.
Our company supplies professional diffusers for ozonation of water, olive oil and other liquids. The diffuser is individually selected to the needs of the task.