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The so-called "white pollution garbage" is an image title for the environmental pollution caused by plastic garbage (mostly plastic bags) that is difficult to degrade. It refers to all kinds of household plastic products made of polystyrene, polypropylene, polyvinyl chloride and other polymer compounds, which are discarded as solid waste after use, and are difficult to degrade because of littering, resulting in serious pollution of the urban environment. Therefore, it is now advocated not to use or use less plastic packaging materials that are difficult to degrade. It is best to bring your own tools to buy things and reduce its use. Polyethylene: Polyethylene is a thermoplastic resin, which is formed by addition polymerization of ethylene. According to different polymerization conditions, polyethylene with relative molecular weight ranging from tens of millions can be obtained. Polyethylene is white particles or powder, translucent, non-toxic and tasteless, and has good chemical stability. Acid and alkali corrosion resistance. Commercially, polyethylene is divided into low density, medium density and high density. Generally, low density (0.92g/cm3-0.93g/cm3) polypropylene without plasticizer is used for packaging: the relative molecular weight is between 80,000 and 200,000. The main chain of polypropylene has a methyl side chain. If all methyl groups are distributed on one side, it is called isotactic polypropylene. If methyl groups are regularly distributed on both sides of the main chain, it is called syndiotactic polypropylene; If methyl groups are randomly distributed in the main chain, it is called random polypropylene. Polypropylene is usually a translucent solid, odorless and nontoxic, with a density of (0.90 g/cm3-0.9 1g/cm3), which has higher mechanical strength and better heat resistance than polyethylene. Among the three kinds of polypropylene, isotactic polypropylene has the largest output. Titanium trichloride-diethyl aluminum chloride is used as a catalyst for polymerization of propylene in saturated gasoline. Isotactic polypropylene (PP) and polyvinyl chloride (PVC) were obtained. The relative molecular weight is 50000-65438+200000. PVC is a thermoplastic resin obtained by free radical addition polymerization. It is an amorphous white powder with a density of (65,438+0.35g/cm3-65,438+0.45g/cm3) and has good chemical stability. It is melted in cyclic ethyl ketone. Toluene-acetone mixed solvent, etc. Polystyrene: The average relative molecular weight is about 200,000. It is a colorless and odorless transparent resin with good light transmittance. Its surface is shiny and flammable, and its density is (1.05g/cm3-1.07g/cm3). It has excellent water resistance, corrosion resistance and electrical insulation. Production methods: bulk polymerization and suspension polymerization. Emulsion polymerization. This paper introduces the ontology polymerization method. Initiator and a small amount of additives were added to styrene monomer, and then low-temperature polymerization was carried out in a prepolymerization kettle to prepare prepolymer, which was then transferred to a polymerization tower for high-temperature heating and kept at a certain temperature in stages. After the reaction, the molten polystyrene is extruded into strips, cooled and hardened in water, and cut and packaged. These are the main components of "white pollution". In addition, plasticizers, foaming agents and packaging are added to these pollutants.

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First, too much land has been occupied. Plastic waste stays in nature for a long time, generally up to 100-200 years. Secondly, it pollutes the air. Plastics, scraps of paper and dust fly with the wind. Third, pollute the water. Plastic bottles and lunch boxes floating on rivers and seas, plastic bags and bread paper hanging from branches above water not only cause environmental pollution. Moreover, if animals eat white garbage by mistake, it will harm their health and even starve to death because they can't digest it in the digestive tract. Fourth, there are fire hazards. White garbage is almost combustible, and methane and other combustible gases will be produced during natural stacking, which is easy to pollute white garbage in case of open fire or spontaneous combustion.

Fire accidents often cause great losses. Fifth, white garbage may become a nest of pests, which can provide food, shelter and breeding places for mice, birds and mosquitoes and flies, and the residues in it are often the source of infectious diseases. Sixth, after the waste plastic packaging enters the environment, it is difficult to degrade, causing long-term and deep-seated ecological and environmental problems. First, waste plastic packaging is mixed in the soil, which affects the absorption of nutrients and crops. As a new material, plastic products have the advantages of light weight, waterproof, durability, mature production technology and low cost, and are widely used in the world. The growth rate of plastic packaging materials in the world market is higher than other packaging materials. 1990- 1995, the average annual growth rate of plastic packaging materials is 8.9%. China is one of the top ten countries producing and consuming plastic products in the world. 1995, the plastic output in China is 5 190000 tons, and the imported plastic is nearly 6 million tons. The total consumption of plastics in that year was about 165433. Among them, the plastic used for packaging reached 265,438+0,654,38+0,000 tons. Most plastics used for packaging are discarded in the environment in the form of waste films, plastic bags and foamed plastic tableware. These waste plastic packages are scattered in urban areas, scenic spots, water bodies and roads, which not only affect the landscape and cause "visual pollution", but also cause potential harm to the ecological environment because it is difficult to degrade. According to the survey, Beijing's domestic waste accounts for 7% of Shanghai's domestic waste, which is packaged in waste plastic, with an annual total of about 6.5438+0.9 million tons. In Tianjin, waste plastic packaging also exceeds 6.5438+0 million tons. In Beijing, about 2.3 billion plastic bags and 220 million disposable plastic tableware are discarded in the environment every year. The abandoned agricultural film is about 6.75 million square meters. People call it "suburban white". White pollution is a unique environmental pollution in China. A large number of waste plastic products can be seen everywhere in various public places. They come from nature and are made by human beings, but when they finally belong to nature, they are not easily absorbed by nature, thus affecting the ecological environment of nature. From the perspective of saving resources, since the main source of plastic products is exhausted petroleum resources, it should be recycled as much as possible. However, because the production cost of recycling at this stage is much higher than the direct production cost, it is difficult to do so under the current market economy conditions. Faced with the increasingly serious problem of white pollution, people hope to find a plastic substitute that can replace the existing plastics without causing white pollution, and degradable plastics emerge as the times require. This new functional plastic is characterized by obvious changes in its chemical structure under certain environmental conditions when it is discarded after reaching a certain service life, resulting in some performance losses and appearance changes, which is harmless or less harmful to the natural environment. For example, starch-filled plastics are rapidly decomposed by amylase secreted by microorganisms in the soil in a short time, which leads to the decline of mechanical properties of the film. At the same time, the self-oxidant added in the formula reacts with metal salts in the soil to generate peroxide, which breaks the chain of polyethylene and degrades it into easily degradable polyethylene.

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With the accelerated pace of people's life, social life is developing in a convenient and hygienic direction. In response to this demand, disposable foamed plastic lunch boxes and plastic bags frequently enter people's daily lives. The appearance of these convenient and low-cost packaging materials has brought a lot of convenience to people's lives. On the other hand, these packaging materials are often discarded after use, resulting in "white pollution". It has become a huge environmental problem. The so-called "white pollution" refers to the environmental pollution caused by discarded agricultural films, plastic films for packaging, plastic bags and disposable plastic tableware (hereinafter referred to as plastic packaging). Because most waste plastic packaging is white, it is called "white pollution". China is one of the top ten countries producing and consuming plastic products in the world. 1995 The total plastic consumption in China was about 1 1 10,000 tons, of which 2 1 1 10,000 tons was used for packaging. Most of the plastics used for packaging are discarded at will in the form of waste films, plastic bags and foamed plastic tableware. 7% of domestic waste in Shanghai is packaged in waste plastics, with an annual output of about 6.5438+0.9 million tons. Waste packaging plastics abandoned in the environment not only affect the city appearance and natural landscape, but also cause "visual pollution", and because it is difficult to degrade, it will also cause potential harm to the ecological environment, such as: mixing into soil, affecting the absorption of nutrients and water by crops, leading to crop yield reduction; The seepage of plasticizers and additives will lead to groundwater pollution; Burning with municipal waste will produce harmful gases, pollute the air and endanger human health; Landfill will occupy land for a long time and so on. The annual white pollution control fund in China is about18.5 million.

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The main hazards of "white pollution" are "visual pollution" and "potential harm" 1 and "visual pollution". Waste plastic packaging scattered in cities, tourist areas, water bodies and roads brings bad stimulation to people's vision, affects the overall aesthetic feeling of cities and scenic spots, destroys the cityscape and causes "visual pollution". Causes long-term and deep-seated ecological and environmental problems. First, the mixing of waste plastic packaging materials into soil will affect the absorption of nutrients and water by crops, leading to crop yield reduction; Second, waste plastic packaging on land or in water is swallowed by animals as food, which leads to animal death (such cases are common in zoos, pastoral areas and oceans); Third, it is difficult to package and treat the waste plastics mixed with domestic garbage: landfill will occupy a long area, domestic garbage mixed with plastics is not suitable for composting, and the sorted waste plastics are difficult to recycle because they cannot guarantee the quality. At present, people mainly reflect the problem of "visual pollution", but most people still lack understanding of the long-term and deep-seated "potential harm" of waste plastic packaging.

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1985 The per capita consumption of plastic packaging materials in the United States reached 23.4 kg, and that in Japan was 20. 1 kg. In 1990s, the per capita consumption of plastic packaging materials in developed countries was greater. From the perspective of consumption, it seems that the "white pollution" in developed countries should be very serious, but it is not. The reasons are as follows: First, developed countries have taken strict measures very early. "Visual pollution" has been basically eliminated. Second, the harmless treatment rate of domestic garbage in developed countries is high. At present, a strict classification and recycling system has been established, and most of the waste plastic packaging materials have been recycled, and a few have been converted into energy or treated harmlessly in other ways, basically eliminating the potential harm of waste plastic packaging materials. The United States has enacted the Law of Resource Protection and Recovery. Technical research, system construction and operation, development planning, etc. Solid waste management, resource recovery, resource protection, etc. There are clear rules. Japan has made special provisions in the Renewable Resources Law, the Energy Conservation and Renewable Resources Support Law, and the Packaging Container Recycling Law. , in order to promote the production enterprises to simplify the packaging and clarify the recycling obligations of production enterprises, sellers and consumers. Germany has clear provisions in the circular economy law. Anyone who manufactures, sells and consumes packaged goods has the obligation to avoid the generation, recycling and disposal of waste. The methods of preventing and controlling "white pollution" in China and their advantages and disadvantages are analyzed. At present, China has begun to take administrative and technical measures to prevent and control "white pollution". Administratively, first, strengthen management. It is forbidden to use disposable plastic packaging materials that are difficult to degrade. Hangzhou is the first city in China to ban the use of disposable foamed tableware. By taking the above measures, the harm of "white pollution" has been alleviated to some extent. However, judging from the results of practice, it is difficult to completely solve the problem of "white pollution" by simple prohibition. The above cities that issued the ban all require paper products or degradable plastic products to replace the original foam plastic products that are difficult to degrade. However, substitutes cannot compete with ordinary plastic products in price and quality. Therefore, under the condition of market economy, it is very difficult to operate only by administrative orders without considering the adjustment of economic leverage. Compulsory recycling. Clean waste plastic packaging can be reused. Or reused in granulation, oil refining, paint making, building materials, etc. Recycling conforms to the general principle of "reduction, recycling and harmlessness" in solid waste treatment. Recycling can not only avoid "visual pollution", but also solve "potential harm", relieve the pressure on resources, reduce the load of municipal solid waste treatment, save land and achieve certain economic benefits. Technically, first, use paper instead of plastic. The main component of paper is natural plant cellulose, which can be easily decomposed by microorganisms in the soil after being discarded, so it can solve the "potential harm" mentioned above, but it will also bring new environmental problems: First, paper needs a lot of wood, and China's forest resources are not rich; Secondly, the paper-making process will bring water pollution. In addition, paper products can't compete with plastic products in performance and cost. At present, China also has the practice of producing disposable tableware with sugarcane stalks and straws as raw materials, but it is still in the experimental stage. Second, use degradable plastics. A certain amount of additives (such as starch, modified starch or other cellulose, photosensitizer, biodegradable agent, etc. ) is added in the production process of plastic packaging products. At present, there are 19 enterprises in Beijing that develop or produce degradable plastics. The test shows that most degradable plastics begin to thin, lose weight, decrease strength and gradually break after being exposed to general environment for three months. If these fragments are buried in garbage or soil, the degradation effect is not obvious. The use of degradable plastics has four disadvantages: First, it consumes a lot of food. Second, the use of degradable plastic products still cannot completely eliminate "visual pollution"; Third, due to technical reasons, the use of degradable plastic products can not completely solve the "potential harm" to the environment; Fourthly, degradable plastics are difficult to recycle because they contain special additives. Third, it is stipulated by law. Through the relevant laws, from June 1 2008, plastic bags will no longer be provided free of charge in supermarkets, and you must pay separately. People want to reduce the use of plastic bags. The main problems in the prevention and control of "white pollution" in China are: 1 There are no special national laws and regulations to prevent and control "white pollution", and it is impossible to rely solely on the consciousness of enterprises or individuals. Compulsory measures should be taken to restrain the behavior of citizens and workers in catering and transportation industries. For example, enterprises or individuals are required to produce, manage and transport themselves. Punish the random discarding and stacking of waste plastic packaging materials. But so far, China has not formulated national laws and regulations in this regard. 2. Lack of relevant economic policies to mobilize the enthusiasm of enterprises to recycle and process waste plastic packaging materials. These enterprises need to give preferential policies. The existing preferential policies for comprehensive utilization are not enough to form a benign market mechanism for recycling waste plastic packaging materials. In order not to increase the burden on the government and to embody the principle of "polluter pays", waste producers should be required to recycle by themselves, and enterprises or individuals who cannot recycle by themselves should pay back the fees to compensate the recyclers. This practice has become more and more common abroad. In China, there is no such economic policy at present. 3. The "white pollution" in cities, scenic tourist areas, traffic trunk lines and waters is mainly caused by poor management. The catering, commercial, railway and water transport departments did not take strict management measures for the waste plastic packaging produced in business activities, and allowed customers to throw it directly on the ground or in the water. Some workers even throw the collected garbage into windows or water. The supporting facilities of urban streets and tourist areas are still not perfect. The density of trash cans in busy areas such as shopping malls, restaurants and parks is too low, and there is no classified trash can. Although the city appearance and environmental sanitation department has regulations prohibiting littering, there are few law enforcement inspectors. It is common that there are laws that are not complied with and prohibitions. 4. Inconsistent management concepts. A considerable number of areas in China do not know enough about the harm of "white pollution", and the prevention and control of "white pollution" has not yet been put on the agenda. Some places advocate using paper instead of plastic or using degradable plastic to solve "white pollution", while others advocate recycling to solve problems. The management ideas are still not unified. People's environmental awareness depends on further improving the environmental awareness of urban residents. Although compared with previous years, they have begun to pay attention to environmental problems, but they have not yet implemented their own actions. Littering, dumping and littering waste plastic packaging can be seen everywhere. News media reports on "white pollution" mostly focus on replacing plastics with paper and using degradable plastics. Lack of guidance and education for residents' daily behavior. Producers, business units and consumers of plastic packaging have no sense of responsibility, no internal motivation to fulfill their obligations, and no external pressure to recycle, utilize and dispose of waste plastic packaging.

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Summarizing the practical experience of preventing and controlling "white pollution garbage" at home and abroad, and combining the present situation of "white pollution" and the problems existing in its management, the prevention and control of "white pollution" in China should follow the principle of "publicity and education as the guide, strengthening management as the core, recycling as the main means and product substitution as the auxiliary means". To prevent "white pollution", we must first solve the problem of "visual pollution" and make the city look and the landscape beautiful. At the same time, it is necessary to strengthen management according to law, urge enterprises and individuals to properly collect and dispose of their own waste plastic packaging, prevent "white pollution", and more importantly, solve the long-term and deep-seated harm of waste plastic packaging to the ecological environment. This is mainly through the formulation and implementation of laws and economic policies conducive to recycling, comprehensive recycling of waste plastic packaging; In order to prevent "white pollution", we should also strengthen the research and development of practical alternative (green) packaging products. In order to speed up the prevention and control process of "white pollution" in China, the following countermeasures and suggestions are put forward: 1, and publicity and education should be strengthened. Preventing and controlling "white pollution" is a systematic project, which requires the joint efforts of all departments and industries and the active participation of the whole society and all citizens. We should vigorously carry out publicity and education. Raise people's awareness of the harm of "white pollution", raise the environmental awareness of the whole society, and educate people to develop good hygiene habits and anger. While strictly abiding by environmental laws and regulations, we should actively stop bad behaviors around us. 2. Unify ideological understanding and strengthen management. According to the prevention and control principle of "publicity and education as the guide, strengthening management as the core, recycling as the main means and substitute products as the auxiliary means", the prevention and control of "white pollution" should be strengthened, and the industries that produce a large number of waste plastic packaging materials (such as railways, water transport, civil aviation, tourism, restaurants, catering, retail and so on) should be strengthened. ), it is necessary to strengthen management and change the phenomenon of unattended, disorderly stacking and random abandonment; Third, take compulsory measures to start with the recycling of waste plastic packaging materials (such as disposable foamed lunch boxes) and gradually improve the recycling rate of waste plastic packaging materials; Fourth, strengthen the development and research of alternative packaging products, and strive to reduce the number of waste plastic packaging. 3. Formulate and promulgate relevant national laws and regulations to prevent and control "white pollution" as soon as possible, and clarify the obligations and legal responsibilities of producers, sellers and consumers to recycle waste plastic packaging. We should formulate specific control measures and guiding policies for the production, operation and consumption of plastic packaging. 4. Formulate appropriate economic policies, establish a benign operation mechanism to eliminate "white pollution" under market economy conditions, encourage and promote "reduction, recycling and harmlessness" of waste plastic packaging by economic means, save and comprehensively utilize resources, prevent and control "white pollution" and protect the ecological environment.