There is no doubt about the thoroughness of ozone sterilization. The main causes of water crisis are waste, pollution, uneven water distribution and irrigation, of which about 550 million cubic meters of water is polluted every year. As an efficient disinfectant and antidote, ozone naturally attracts many scientists to study the technology of applying it to water pollution control and industrial water saving. The U.S. Groundwater Technology Company has successfully treated soil and groundwater pollution through ozonation technology. The company's experiments show that ozone oxidation technology can eliminate 35 ~ 98% toxic substances in a few months, and it takes several years for these toxic substances to be treated by traditional methods such as volatilization and biodegradation. Studies show that toxic hydrocarbons in industrial wastewater can be oxidized and decomposed by ozone combined with ultraviolet radiation, and heavy metal ions can be removed at the same time. The purification rate of this method in dye wastewater treatment reached 95%, which was 25% higher than that of the traditional method. The treated industrial sewage can be recycled, which avoids soil and water pollution and saves industrial water. In developed countries, ozone technology has also been applied to drinking water treatment and seawater desalination.
In addition to these fields, ozone technology is also used in aquaculture, fishery, agriculture, food processing industry and other fields. Hospitals are places where diseases are treated. However, because most of the patients who come to the hospital are critically ill, their inflammation is at its peak, and harmful bacteria from patients can easily spread in the air. Therefore, the hospital is also a place prone to diseases. Therefore, it is common to go to the hospital to cause cross infection. Disinfection of doctors' or nurses' hands and surgical instruments before hospital operation and nursing operation is also one of the urgent problems to be solved. Ozone with high efficiency and rapid sterilization is of great use in hospital environment disinfection and preoperative disinfection. For example, Japanese scientists have studied ozone water disinfection for hospitals. According to the research results, disinfection of doctors and nurses' hands with ozone water before hospital operation can kill all bacteria, not only in a very short time, but also its disinfection effect is incomparable with other iodine-containing disinfectants. Traditionally, the same disinfection operation takes at least 10 minutes. Staphylococcus aureus and Pseudomonas aeruginosa, which are most likely to cause hospital infection, can be completely killed in ozone water in only 5 seconds, and their bactericidal power far exceeds that of alcohol and chlorine. Moreover, ozone water is reliable and safe, and it will not harm the skin if used frequently, and it will not be poisoned even if it is drunk by mistake.
Ozone can also be used for treatment. For example, Russia has developed a special hydraulic fluid to heal wounds. The basic method is to wash the wound with a foggy physiological solution rich in ozone under high pressure. The water flow is like a scalpel to remove pus, necrotic tissue and bacterial decomposition in the wound, and at the same time kill pathogenic microorganisms in the wound. Then change the structure of the "ozone knife", continue to increase the pressure of the liquid, make the ozonated solution penetrate into the inflamed tissue to a depth of several millimeters to 3 centimeters, and increase oxygen to kill the deeper pathogenic bacteria. It is reported that 200 patients have been treated by this method, all of whom have diabetes, septicemia, arteriosclerosis and are not suitable for ordinary surgery. As a result, the wounds of these patients have completely healed. During the production of beverages and fruit juices, the pipelines, production equipment and containers can be soaked and cleaned with ozone water, thus achieving the purpose of disinfection and sterilization. Using this soaking and washing method, firstly, a large number of bacteria and viruses on the surfaces of pipelines, equipment and containers are washed away; Secondly, ozone is used to kill the bacteria and viruses remaining on the surface that have not been washed away, which is very simple and convenient, and there is no dead angle in production, completely avoiding the discharge and residue of chemical toxic substances caused by the use of chemical disinfectants in production. In addition, using ozone water to sterilize production equipment, combined with membrane separation process and aseptic filling system, can be used in the production of soy sauce, vinegar and alcohol in brewing industry, and improve the quality and grade of products.
In the application of vegetable processing, such as small packaged vegetables such as traditional mustard tuber, radish, cucumber and other food processing, many enterprises often use high-temperature sterilization after packaging to extend the shelf life of products, which not only adversely affects the color and texture of products, but also consumes a lot of energy. The new technology of ozone water cooling sterilization can avoid the adverse effects of traditional processing technology on product quality, improve product quality and reduce production cost.
Application in aquatic product processing, in the pre-freezing treatment of frozen aquatic products, ozone water spray sterilization can play a very good role in controlling the sanitary index of aquatic products.
The application in cold storage mainly includes three aspects: first, killing microorganisms-disinfection and sterilization; The second is to oxidize and deodorize all kinds of odorous inorganic or organic substances; The third is to oxidize metabolites, thus inhibiting metabolism.
Replacing ultraviolet disinfection lamp in food processing environment, widely used for disinfection of processing environment. Modern industrialized poultry breeding, especially chicken production, has reached a transition period, that is, from popularization to improving production efficiency and product quality. In the transitional period, traditional technology has exposed obvious weaknesses. As far as the key measures to prevent epidemic diseases in chicken production are concerned, it is necessary to find a new breakthrough in technology to improve production efficiency and product quality. In the routine feeding process, chickens are only given antibiotics and vaccinated continuously. These measures seem beyond reproach, but they ignore the sterilization, disinfection and purification of indoor air all the time during the feeding process. Excessive use of chemicals will damage the calcium absorption function of laying hens. The calcium absorption function of laying hens is temporarily damaged, even if calcium-containing feed is added, the effect is not great, and soft-shell eggs are bound to be produced. In the process of chicken production, it is difficult to avoid the loss caused by epidemic disease without feeding antibiotics and other drugs to chickens, and feeding antibiotics and other drugs affects the quality of products, which is really a dilemma. When ozone is filled into the feeding shed, it first decomposes with the odor emitted by poultry manure to remove the odor. When the odor is removed to a certain extent and the ozone is slightly smelled, the viruses such as Escherichia coli, Staphylococcus, plague in Xincheng, chicken cholera and avian influenza in the shed are basically killed. In addition, the toxicity of amine gases emitted by poultry excreta to poultry can not be ignored, and the harm of toxic gases such as sulfur oxide produced by rural farmers in direct heating in breeding sheds in winter to poultry can not be eliminated by chemical drugs. However, after the application of ozone technology, it can effectively achieve the purification effect, and when it enters the breeding shed of ozone technology, it intuitively makes people feel that the air is obviously fresh.
While using ozone to disinfect and purify the air in farms, it is also an important link to brew ozone water for poultry to drink. Drinking ozone water can change the microecological environment of poultry intestines. Ozone reduces the number of bacteria living on host nutrition in poultry intestines and reduces the consumption of host nutrition. It can also enhance the activity of exuberant amylase. Improve the utilization rate of food nutrients by poultry, especially young birds, increase the nutritional supply of young birds, and promote the healthy growth of poultry. Letting birds drink ozone water can change the drug resistance of birds, which can effectively prevent intestinal diseases such as pullorum. It should be pointed out that the half-life of ozone in water is about 20 minutes, and it is best to drink while doing it. But ozone breaks down chemicals. Drug supply and ozone water supply should be separated and more advanced.
Through a large number of field application comparisons, ozone effectively curbed the occurrence of poultry diseases, ensured the survival rate of poultry and promoted healthy growth. Farmers are very satisfied, and the economic benefits and social effects are remarkable. Generally, the period of raising broilers is 50 days, which can be advanced by one week after applying ozone technology, and there is almost no death due to illness, so chicks are particularly energetic; Laying hens can maintain a stable egg production rate, which has been greatly improved from the comparison. Ozone is a colorless gas with a slight odor. When dissolved in water, it will become a strong oxidant and have a strong killing effect on living cells. Through the ozone generator, the oxygen in the air can be converted into ozone under the ionization of high-voltage electricity and high-frequency electricity, and then used for production. Using ozone generator, the author conducted an experimental demonstration of using ozone to control vegetable diseases and insect pests in greenhouse around Xi 'an, and achieved good results.
Advantages of ozone in pest control;
Safety, high efficiency and low cost. Ozone can be used for multiple purposes, and at the same time, it can control a variety of pests and diseases with low control cost. Compared with spraying pesticides, ozone application is more convenient, efficient and safe, which can greatly reduce the use of pesticides and avoid vegetable farmers from applying highly toxic and residual pesticides, thus reducing the cost of medication; Pollution-free ozone is unstable in dry air and can be quickly decomposed into oxygen, so it has no pollution and residue in plants and fruits, which is an important way to realize pollution-free vegetable production. Improve quality and increase output. After the experiment, the abnormal fruit of tomato in greenhouse was obviously reduced, the yield was increased by about 20%, and the fruit was large, colorful and delicious.
How to use:
Seed treatment. Introducing ozone gas into clean water, and continuously stirring for 65438+/-00 minutes to obtain ozone solution. Soak the seeds in it for 15-20 minutes to kill viruses, germs and eggs on the surface of the seeds; Pest control in greenhouse: greenhouse fumigation. Before planting 10 day, ozone generator can be combined with high temperature closed shed to apply ozone in the shed, and the application time should be no less than 2 hours; Control seedbed diseases and insect pests. 1, sealing the seedbed, applying pesticide every 1 0m2, fumigating for10min, and then ventilating for 30min; Pest control of protected vegetables after planting. After slowly planting seedlings, ozone is continuously applied for 7- 10 minutes per mu of shed, then closed fumigation 15-20 minutes, and then ventilated for 30 minutes. In the shed free of pests and diseases, apply 1 time every 5-7 days, apply for 5 times continuously, and increase the application time for 5 minutes every 2-3 times until it reaches 25 minutes per mu. The fumigation time is also increased by 5- 10 minute every 2-3 times. Experiments show that ozone has a good control effect on tomato gray mold, leaf mold, early blight, late blight, cucumber downy mildew and blight, as well as greenhouse whitefly, leaf miner and aphid. However, it has no effect on pests and diseases in greenhouse soil, because the amount and concentration of ozone gas infiltrating into soil are too small.
Precautions:
Reasonable determination of application amount and fumigation time. The ozone dosage and fumigation time in closed shed should be adjusted according to different crops and their growth periods. Generally speaking, growing crops are more adaptable to ozone than seedling crops. If the amount of ozone is too large or the fumigation time in the greenhouse is too long, the leaves and flowers of vegetables in the greenhouse will be poisoned and dried up, and in serious cases, the plants will die. With the growth of plants, the application amount and fumigation time can be gradually increased to achieve the purpose of controlling pests and diseases without harming vegetable crops. The release should be as uniform as possible, and the air nozzle should not be directly directed at the vegetables, but should be away from the vegetable plants for more than 0.8- 1 meter. Ventilation should be timely after the fumigation time arrives, and the general ventilation time should not be less than 30 minutes; Temperature and humidity control. When ozone is applied, the indoor temperature should be kept within the range of 10-30℃, and the control effect will be better under the condition of high air humidity. Prevent people and animals from entering the greenhouse during fumigation to avoid poisoning or other adverse reactions?
8。 Method and principle of ozone detection
1. The basic principle of ozone concentration detector comes from Ansrose company in Germany.
1. 1 detection principle
We know that there is ozone layer in the earth's atmosphere. Scientists found that the ozone layer can absorb ultraviolet rays. The results show that ozone has the maximum absorption coefficient only for ultraviolet rays with the wavelength of 253.7nm, and ultraviolet rays will be attenuated by ozone at this wavelength, which conforms to lamport-Beer law. In the United States and other countries, this method has been used as the standard ozone analysis method. Ozone detector adopts the principle of ultraviolet absorption, uses a stable ultraviolet light source to generate ultraviolet light, and uses a light wave filter to filter out ultraviolet light with other wavelengths, allowing only light with a wavelength of 253.7nm to pass through. After passing through the sampling photoelectric sensor and ozone absorption cell, it reaches the sampling photoelectric sensor. The ozone concentration can be calculated by comparing the electrical signals of the sample photoelectric sensor and the sampling photoelectric sensor, and then by mathematical model.
1.2 ozone concentration detector
Mathematical calculation model of concentration
The mathematical model of ozone concentration (such as formula 1) comes from Lambert and Beer's law.
-in I/I0
C = ———
E×D (formula 1)
(Note: C- ozone concentration, in grams/meter; E constant; D- the distance of ozone absorption pool;
I0- sampling current; I- sampling current)
In this ozone concentration calculation formula, the ozone concentration can be calculated as long as the sampling current, the sampling current and the distance from the ozone absorption pool are known. Due to the limitation of the distance of ozone absorption pool, the maximum ozone concentration can only be measured to 300 o3g/m. ..
Realization of 1.3 circuit principle
The basic circuit consists of six parts: power supply, ultraviolet lamp control, ultraviolet sampling detection, ultraviolet sampling detection, logarithmic amplifier Log 100, analog output and display.
The core part of the circuit is to realize the mathematical model of ozone concentration with Log 100 logarithmic amplifier. LOG 100 is an integrated circuit, and its pin 14 can perform logarithmic operation on the ratio of two currents or voltages. The output current of the amplifier has a wide dynamic range, which can vary from 1nA to 1mA. The output error range is less than 0. 1%. Basic wiring (as shown in figure 1), output formula: Vout =VT×ln I0/I (note: VT-constant; Vout-output voltage).
The power supply part is mainly the high-voltage power supply needed to generate the ultraviolet lamp, and at the same time, it generates the required+15V DC on the circuit board. The lamp control part of the ultraviolet lamp mainly controls the lamp current of the ultraviolet lamp in a constant allowable range. If it is too high or too low, it can be adjusted automatically. If it can't be adjusted, it means that the life of the ultraviolet lamp has reached, and a red light on the panel is on, prompting you to replace it with a new ultraviolet lamp. Standard ultraviolet detection and sampling ultraviolet detection are also key parts. The photoelectric sensor converts the ultraviolet signal into a voltage signal, which is amplified by two operational amplifiers and sent to LOG 100 for calculation and display. The 0~20mA analog output has a linear relationship with ozone concentration.
2. Ozone concentration detector
Basic structure
The detector is mainly composed of low-voltage ultraviolet lamp, light wave filter, incident ultraviolet reflector, ozone absorption cell, sample photoelectric sensor, sampling photoelectric sensor, output display and circuit elements. (as shown in figure 2)
3. Main technical indicators
3. 1 displayable unit: O3 g/m, mg/m; parts per million
3.2 measuring range: 0 ~ 10o3g/m, 0 ~ 10o3g/m, 0 ~ 200o3g/m.
3.3 detection limit: 10 ppb
3.4 Display accuracy: +65438+ 0% of reading.
3.5 input power supply: AC110v/ac220v50 ~ 60hz.
3.6 Analog output: 0/4~20 mA
4. Instrument calibration method
4. 1 calibration instrument calibration
The ozone detector of GM-Pro standard of German Ansrose company is adopted, and the distribution of the produced ozone detector is compared with that of 10 test points, and the error range is controlled within+1% to be qualified.
4.2 Chemical titration
Internationally recognized chemical methods, namely potassium iodide and sodium thiosulfate titration, are used to detect ozone concentration. We also selected 10 test points, and then compared them with 10 points measured by ozone detector chemical titration, and the error range was controlled within+1%. The principle of potassium iodide titration is to use strong oxidant ozone to react with potassium iodide, so that iodine is released into water, and the water will turn brown. (Reaction formula: O3+2ki+H2O2+I2+KOH) When titrated with sodium thiosulfate standard solution, the free iodine becomes sodium iodide, and the end point of the reaction is that water completely fades. (reaction formula: I2+2na2so3 2nai+na2s4o6)
Ozone concentration: C= (Ana×B×2400)/V0 unit (mg/l)
(Note: ANA-dosage of sodium thiosulfate standard solution ml; B -- concentration of sodium thiosulfate standard solution mol/l;
V 0- ozone oxidation other sampling volume ml)
5. Ozone concentration detector
conclusion
The ozone concentration detector developed in this paper adopts ultraviolet absorption method, single light source and double light path detection, with small volume, high precision and good stability, and can work continuously. Its measuring range is wide, the maximum measuring range is 300o3g/m, in addition, the detector also has 0/4-20 Ma analog output, which can form an ozone closed-loop automatic control system with ozone generator and PID regulator.
References:
1. Handbook of Ozone Technology and Application, RICE, RIPG, NETZER ANN ARBIR SCIENCE, 1982.
2. Handbook of Ozone Technology and Application Abroad, Wang Wei, Ansrose Company, Germany, 199 1.