Key issues in the application of powdered activated carbon adsorption technology 1. Status The use of powdered activated carbon in water treatment has been around for 70 years. Since the first use of powdered activated carbon in the United States to remove the odor of chlorophenol, activated carbon has become one of the effective methods for removing color, smell, taste and organic matter in water treatment. A large number of studies on the adsorption performance of powdered activated carbon in foreign countries show that the powdered activated carbon contains trichlorophenol, dichlorophenol, organic matter contained in pesticides, trihalomethanes and precursors, and disinfection by-products such as trichloroacetic acid, dichloroacetic acid and dihalide. Acetonitrile and the like have good adsorption effects, and the removal effects on color, smell and taste have been recognized. Powdered activated carbon is widely used in Europe, the United States, Japan and other countries. In the early 1980s, the powdered activated carbon used in water treatment in the United States was about 25,000 tons per year, and it has an increasing trend year by year. At the end of the 1960s, China began to pay attention to the problem of deodorization and deodorization of polluted water sources. Powdered activated carbon has been tried in Shanghai, Harbin, Hefei and Guangzhou. In recent years, China has gradually paid more attention to the research and application of powdered activated carbon. Tongji University and Harbin University of Architecture have made in-depth research and have achieved many practical results. The main features of the application of powdered activated carbon are equipment investment, low price, fast adsorption speed, and strong adaptability to short-term and sudden water pollution. 2 Restrict the bottleneck of technology application According to our research, the application of powdered activated carbon adsorption technology in waterworks is a very promising technology. However, due to the failure to solve the limitations of the technology in application, it is difficult to take advantage of the powdered activated carbon technology, resulting in technical applications can not achieve practical results. Applications in waterworks must address both theoretical and applied issues.  2.1 theoretical problems should be solved (1) According to the water quality of the raw water of the water plant, especially the distribution of the molecular weight of the organic matter, the carbon species to which the powdered activated carbon is added is determined. (2) According to the actual water quality of the water plant, determine the reasonable and economical dosage. (3) According to the existing production process of the water plant, determine the appropriate and reasonable feeding point and dosage method to solve the contradiction between the adsorption competition of powdered activated carbon and coagulant, and improve the efficiency of powdered activated carbon. Under the same conditions, different powdered activated carbon charcoal species have a large difference in the ability of organic matter adsorption treatment (the removal rate differs by 16%). Similarly, according to the characteristics of water plant water production process, the impact of different feeding points is also large, which is mainly due to the characteristics of raw water and the results of competition between coagulation and adsorption, and the determination of dosage should be based on the target expected value in engineering applications. (Factory water CODMn) and operating costs are considered together. As an emergency measure, powdered activated carbon has been tried in some water plants, but the application of this technology has been mixed. Our research shows that, in view of the actual situation of different water plants, it is necessary to explore a suitable way to solve the above three problems; especially for different processing processes, it is crucial to choose reasonable investment points and dosing methods. of. Therefore, in the application of the technology, sufficient attention must be paid to effectively and effectively exert the effect of powder activated carbon to remove pollution.  2.2 problems should be solved in engineering applications (1) The problem of dust pollution in the application. In the application of waterworks, powdered activated carbon is labor-intensive in many processes such as loading, unloading, unpacking, preparation, and dosing, which easily causes dust to fly, resulting in a bad working environment, strong resistance of operators, and also becomes a restriction on powdered activated carbon. A key, substantive issue of technology application. According to the data report, some water plants use negative pressure preparation and dosing methods for powdered activated carbon. This method has basically solved the problem of dust pollution, but it is still difficult to avoid the problem of dust flying and labor intensity caused by powdered activated carbon (20 kg/bag) during handling and unpacking, especially the processing capacity is more than 100,000 m3/ In the waterworks of d, the amount of powdered activated carbon per hour is generally about 60 kg (calculated by the dosage of 15 mg/L). Research report and decolorization effect of powdered activated carbon The use of powdered activated carbon in water treatment has a long history. Since the first time in foreign countries to remove the odor of chlorophenol from powdered activated carbon, powdered activated carbon has become one of the effective methods for removing color, smell, taste and organic matter in water treatment. A large number of studies on the adsorption performance of powdered activated carbon in foreign countries show that powdered activated carbon contains trichlorophenol, dichlorophenol, organic matter contained in pesticides, trihalomethanes and precursors, and disinfection by-products such as trichloroacetic acid and dichloroacetic acid. Dihalogenated acetonitrile and the like have good adsorption effects, and the removal effects on color, smell and taste have been recognized. At present, about 30,000 tons of powdered activated carbon are used in water treatment every year, and there is an increasing trend year by year. China has been paying attention to the problem of deodorization and deodorization of polluted water sources very early. Powdered activated carbon has been used in various industries. China has gradually paid more attention to the research and application of powdered activated carbon, and has achieved many practical results. The main features of the application of powdered activated carbon are equipment investment, low price, fast adsorption speed, and strong adaptability to short-term and sudden water pollution. The problem that powdered activated carbon needs to solve in application: (1) The problem of dust pollution in the application. In the application of waterworks, powdered activated carbon is labor-intensive in many processes such as loading, unloading, unpacking, preparation, and dosing, which easily causes dust to fly, resulting in a bad working environment, strong resistance of operators, and also becomes a restriction powder. A key and substantial problem in the application of activated carbon technology. (2) The problem of accurately preparing and quantifying the addition of powdered activated carbon in the application. In order to stabilize the effect of adsorption and decontamination of powdered activated carbon, it is necessary to ensure the accuracy of dosing and measurement within a certain range, which is not only related to the treatment effect, but also closely related to the cost of water production. The entire powdered activated carbon storage, formulation, dosing equipment or system constructed according to the appropriate parameters must be able to prevent the instability factors caused in various links, such as the blockage problem during the transportation and dosing process, which will cause unstable flow. , thus affecting the effect of decontamination. (3) Automatic control of equipment or systems. In order to further reduce the operation intensity of powdered activated carbon dosing equipment, how to achieve automatic operation, match with the original automatic control system of the water plant and how to automatically track and adjust according to the change of water quality to meet the purpose of stabilizing the effluent water quality, which also restricts the technology. Key factors in the application. (4) The most critical issue in the application of powdered activated carbon technology is investment and cost control, in order to meet the new "Sanitary Standards for Drinking Water" (mainly CODMn <3mg / L, in special cases does not exceed 5mg / L), Most water divisions face problems with technological transformation. For most water divisions, water pollution is generally intermittent or sudden, and conventional processes are able to meet new specifications most of the time, so powdered activated carbon technology is a very practical technology. Its investment is relatively provincial, low cost and flexible. Tips for using activated carbon: 1. The adsorption capacity of activated carbon has a lot to do with its shape. The smaller the particles, the larger the surface area and the better the adsorption effect. On the contrary, the activated carbon adsorption effect of Chengyu is the worst. Therefore, if bulk activated carbon is used, it is best to spread it into a face. 2. The activated carbon placed in the purifier has been used for a long time, and it can be used after being exposed to the sun. 3. In addition to bookcases and drawers, activated carbon can be conveniently placed in small bamboo baskets, in heating hoods or in dishes and flower cabinets. 4. Households using high-grade flooring are suitable for activated carbon, which can extend the service life of the floor.
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