Ozone is chemically very unstable, and is a strong oxidizer that slowly decomposes into oxygen in both air and water. Ozone treatment method is to use ozone decomposition, the generation of new ecological oxygen oxidation and decomposition capacity. This new oxygen acts on the cell walls and cell membranes of bacteria and viruses, etc., and reacts on the double bonds of lipids (lipid-like compounds). In this action, the cell membrane is disrupted and the SH enzyme is destroyed, resulting in a sterilizing effect. In the case of Bacillus bacterial spores, sterilization can be achieved with an ozone sterilizing agent at a concentration of 0.3-0.5mg/l. Lactobacilli are weakly resistant to ozone. It is reported that the initial bacterial count of 2.3-5.6×109/ml, after ozone treatment for 30 seconds, most of the bacteria die.
The bactericidal effect of ozone varies greatly depending on the type of microorganism, which is due to differences in cell walls or cell membranes.
Treating bacterial spores and yeast of the genus Bacillus with ozone takes a long time, but increasing the concentration of ozone can shorten the reaction time appropriately. In actual use, the concentration of ozone and the selected contact reaction time can be determined according to the bacterial species.
Ozone sterilization method according to drinking water standards, contact reaction time of 5-8 minutes, the ozone concentration at the exit of the ozone generator for more than 0.4mg / l (injection rate of 2-3mg / l), the majority of examples of the above conditions for the operation and management of the target. If the ozone injection rate is increased to 5mg/l in the same system, according to the experimental results, the water after such treatment, in general, bacteria can not survive.
In order for the ozone sterilization process to be carried out reliably, it is important to monitor the ozone injection concentration and ozone solubility to keep them within a suitable range. Now, in addition to high-precision continuous ozone concentration meter, inexpensive portable meter has also been developed, so regular ozone concentration test and take remedial measures is also necessary. In the sterilization process of water, it is inevitable that ozone will be discharged outside the system, so it is necessary to carry out decontamination treatment so that the amount of ozone discharged is below the permissible concentration.
Ozone is a harmful gas, the concentration of 6.25 × 10 -6 mol/L (0.3mg/m3), the eyes, nose, throat, there is a feeling of irritation; concentration (6.25-62.5) × 10 -5 mol/L (3 ~ 30mg/m3), headache and respiratory organs, such as localized paralysis; ozone concentration of 3.125 × 10 -4 ~ 1.25 When the concentration of ozone is 3.125×10 -4～1.25×10 -3 mol/L(15～60mg/m 3 ), it is harmful to human body. Its toxicity is also related to the exposure time, for example, long-term exposure to 1.748 × 10 -7 mol/L (4ppm) below the ozone will cause permanent cardiac disorders, but exposure to 20ppm below the ozone is not more than 2h, there is no permanent harm to the human body. Therefore, the permissible value of ozone concentration is set at 4.46×10 -9 mol/L (0.1ppm) 8h. Because of the strong odor of ozone, the concentration of 4.46×10 -9 mol/L (0.1ppm), people feel, therefore, the world has been using ozone for more than a hundred years, and so far there has been no case of ozone poisoning has not been found due to ozone poisoning and death reports.
Ozone has a very strong oxidizing properties, in addition to gold and platinum, ozonized air almost all metals have corrosive effects. Aluminum, zinc, lead and ozone contact will be strongly oxidized, but chromium-containing iron alloys are basically not corroded by ozone. For this reason, ferrochrome alloys (stainless steel) containing 25% Cr are often used in the manufacture of ozone generating equipment and filling equipment in direct contact with ozone.
Ozone also has a strong corrosive effect on non-metallic materials, even if used elsewhere in a fairly stable polyvinyl chloride plastic filter panels, etc., in the ozone refueling equipment soon to be used in the loosening, cracking and perforation. In the ozone generating equipment and metering equipment, can not use ordinary rubber as a sealing material, must use corrosion-resistant silicone rubber or acid-resistant rubber.
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