standard, then it is certainly used to sterilization, currently the most used in the water treatment industry is the ultraviolet sterilization and ozone sterilization, both of which is the use of ultraviolet lamps for sterilization, one in the water with ozone, which in essence there is not much difference between the two are sterilized! Sterilization, but that effect is better? For this technical problem, the following analysis of the two product technology issues. Food industry water treatment process ozone
The water quality used must meet the drinking water standards. Some must be in the water quality limit concentration standard preparation within the paradigm turn, and even, according to the requirements of the use of sterile water, due to the type of final product of the food industry and the size of the plant is different, the situation is also various. If you do not take into account the economics of the entire operation and maintenance and management issues, then, in the final stage of the use of 0.22um or 0.45um membrane filter (MF), it is possible to achieve effective sterilization.
Ozone is a strong oxidizing agent. The ozone treatment method utilizes the oxidizing effect and decomposing ability of the new ecological oxygen generated when ozone decomposes. Oxidation of inorganic matter A Removal of metal ions: iron removal, manganese removal, decomposition of organic metal compounds; Removal of harmful substances: cyanide, NOx, SOx; oxidative decomposition of nitrous acid and so on. Alteration of Organic Matter A Decolorization; B Reduction of Odor; C Pretreatment for Supporting the Removal of Organic Matter; Improvement of the Absorption of Activated Carbon; D Biological Removal: Sterilization, Non-Activation of Case Poisoning; E Removal of Sludge, F Synthesis of Organic Matter, Manufacture of Vitamins; Manufacture of General Pharmaceuticals Complete Oxidation of Organic Matter.
The ultraviolet irradiation sterilization of water is not a new addition to any impurity in the water, nor is it to make any chemical changes in the treated water, but rather in a very short period of time within the memory of its equipment to complete the sterilization process. Therefore, the UV sterilization method is mostly applicable to clean production water sterilization. In terms of microbiological control of instrumented factory water, the strains of bacteria associated with the deterioration of the quality of the product and spoilage are general bacteria of the genus Bacillus, wild yeasts, filamentous fungi, and so on.
Ozone treatment method, in addition to the sterilization effect, there are decolorization, deodorization, so that difficult to decompose substances into easy to decompose substances, flocculation improvement and improve purification capacity. Therefore, in the factory water and treatment, ozone has a wide range of applications, can be used to deal with both the raw water system, production water, but also can deal with drainage,, but, as the production of water used to bacterial means,, the ozone treatment method of the composite effect in some occasions is not popular. Two ozone sterilization method
1 ozone sterilization mechanism and sterilization characteristics: ozone decomposition generates oxygen and new ecological oxygen. This new ecological oxygen role in bacteria and viruses and other cell walls and cell membranes, reaction in the lipid (lipoidal complex) of the double bond. In this action, the cell membrane is destroyed and the SH enzyme is destroyed, resulting in sterilization. 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. According to the drinking water standard ozone sterilization method, contact reaction time for 5-8 minutes, ozone concentration at the outlet of the ozone generator for more than 0.4mg / l (injection rate of 2-3mg / l), the majority of instances of the above conditions for the operation and management objectives. 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.
The bactericidal effect of ozone, due to the different types of microorganisms and there is a big difference, which is due to the differences in the cell walls or cell membranes to move into. With ozone treatment of bacterial spores and yeast of the genus Bacillus, it takes a long time, but if you increase the concentration of ozone can make the reaction time is appropriate to shorten. In the actual use of the process, according to the strain to determine the concentration of ozone and selected contact reaction time.
2 water ozone sterilization method, not only a sterilization device, but should be regarded as a sterilization system. In order to establish such a system, the precautions to be taken.
A ozone raw material refining: In addition to the use of fluorescent lamps to produce ozone or refrigerated storage of small ozone machines, for industrial-scale ozone generators, as ozone raw material air refining decontamination, dust, dehumidification is very important, in general: the concentration of ozone produced by the silent discharge ozone generator to the air as a raw material for the 1-3% to oxygen as a raw material for the 2-6% if the refining process is not adequate, the ozone generator should be considered as a sterilizing system. This refining process is not sufficient, then, there are only ozone production efficiency is low, and raw materials in the impurity of the original, part of the nitrogen oxides in the form of ozone treatment of the water system.
B selected with stable ozone production capacity of the ozone generator that seat is recommended to use ozone generators. In recent years, the development of ozone generators and technology level has improved significantly. Ozone generators sold on the market, various types are available, such as silent discharge glass tube type, the same pole plate type, ceramic surface discharge type, etc., Mitsubishi Electric, Sumitomo Precision, Fuji Electric and other first-class manufacturers of products, its performance has reached the international advanced level. From small 15G/H machines to large 40KG/H machines, they can be used in PSA oxygen generators for ozone feedstock, forming a series of products. Recently joined the ranks of manufacturers of large hand machinery manufacturing company, launched a portable ozone machine.
The ozone sterilization method of production water used for food manufacturing, it is best to use pure oxygen or PSA oxygen concentrator to supply ozone material.
C Contact reaction time between water and ozone: The amount of ozone injected and the contact reaction time depend on the type of microorganism that is the object of sterilization and the target sterilization rate. It may be due to the construction cost,
D Management of Ozone Concentration: In order to make the ozone sterilization process reliable, it is important to monitor the ozone injection concentration and ozone solubility, to control them in a suitable range. Nowadays, in addition to high-precision continuous ozone concentration meters, inexpensive portable meters have also been developed, so regular ozone concentration tests and remedial measures are also necessary. In the process of sterilizing water, it is inevitable that ozone is 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. Three ultraviolet irradiation sterilization method 1 ultraviolet sterilization mechanism and processing characteristics wavelength 200-290mm of ultraviolet light, can be through the cell membrane of bacteria or viruses controlling the genetic phenomena and biological functions of nucleic acid (DNA) caused by damage to the loss of its ability to reproduce, so as to achieve the purpose of sterilization.
Various microorganisms sensitive to ultraviolet light, due to the different strains of bacteria and there are differences. According to the Bacillus genus (Bacillus) as the object (including B.subtlis) for the plant test results show that in the irradiation amount of D10 = mw.s/cm2, the sterilization rate of 99.5%. For this reason, the actual device is designed to irradiate an amount equivalent to D10 × 4, i.e., more than 50 mw.s/cm2.
Nucleic acid (DNA) has a tendency to be particularly easily absorbed by ultraviolet light with a wavelength of 250-260mm. This is why UV at this wavelength has the strongest germicidal ability. In accordance with the microorganisms to be killed by the amount of ultraviolet irradiation required to carry out the bacterial treatment, but does not make any changes in water quality, in a very short period of time for a flash sterilization, the effect is good. Moreover, this treatment is accomplished in a straight-pipe flow type device.
In terms of ultraviolet sterilization, the size of the bactericidal force relative to the amount of ultraviolet irradiation when treating water mw.s/cm2 (ultraviolet irradiation intensity [mw/cm2 × time]) to indicate. The size of the amount of UV illumination shot has a correlation with the size of the sterilization rate.