white pollution
white pollution is a unique environmental pollution in Chinese cities. A large number of discarded plastic products can be seen everywhere in various public places. They come from nature and are made by human beings, but they are not easily absorbed by nature when they are finally attributed to nature, thus affecting the ecological environment of nature. From the perspective of saving resources, plastic products should be recycled as much as possible because the main source is exhausted petroleum resources, but the production cost of recycling at this stage is much higher than the direct production cost, which is difficult to do 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 plastic properties without causing white pollution. Degradable plastics emerge as the times require. This new type of functional plastic is characterized by its degradation due to obvious changes in its chemical structure under certain environmental conditions after reaching a certain service life, which is harmless or less harmful to the natural environment. For example, starch-filled plastics, first of all, the starch contained in it is rapidly decomposed by amylase secreted by microorganisms in the soil in a short time, resulting in the decrease 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 small fragments that are easily swallowed by microorganisms and is absorbed by the natural environment, and at the same time plays a role in improving the soil.
The earth is our home, and this home is surrounded by garbage. As the masters of the 21th century, we should not just worry and complain, but take action and be green. Garbage is not useless, and waste products are not useless. It is not difficult to recycle and recycle garbage technically, but the difficulty lies in that the waste is discarded casually and mixed and piled up to become garbage; Therefore, as educated civilized people in the new century, we should participate in the "easy" garbage source classification activities, make a little contribution to purifying our living space, and offer a piece of love.
Domestic garbage is a by-product of human life. With the rapid development of social economy and the high concentration of urban population, the output of domestic garbage is gradually increasing. General domestic waste can be divided into five categories: waste paper, plastic, glass, metal and biological waste. The main hazards of garbage to human life and environment are:
First, it occupies too much land. Garbage piled up in the suburbs of the city has occupied a lot of farmland. At present, the average annual output of garbage in Beijing is 441 kilograms per person, and the annual output of the whole city is about 4 million tons, which is equivalent to two and a half scenic mountains. There are more than 4,511 garbage dumps in Beijing, covering an area of over 1,111 mu. Garbage stays in nature for a long time: cigarette butts and wool fabrics are 1-5 years; Orange peel for 2 years; Painted wooden board in 2113; Nylon fabric for 31-41 years; Leather for 51 years; 81-111 years of cans; Plastics in 111-211 years; Glass for 1111 years. To this end, we should not only make less garbage, but also pay attention to the classification and recycling of garbage, so as to turn waste into treasure. Use less disposable chopsticks, cups, lunch boxes and other products, and use more reusable products to reduce the consumption of precious forest resources; Use less plastic bags and use shopping bags to reduce the harm of "white pollution" in cities; Buy fluorine-free refrigerators, air conditioners and other environmental protection appliances to protect the atmospheric ozone layer; Use less high-concentration detergent and phosphorus-free washing powder to reduce water pollution.
second, pollute the air. Garbage is a complex mixture. In the process of transportation and open-air stacking, organic matter decomposes to produce stench, and releases a large number of pollutants such as ammonia and sulfide to the atmosphere, including more than 111 kinds of organic volatile gases, which contain many carcinogens and teratogens. Plastic film, paper scraps and dust fly with the wind to form "white pollution".
third, pollute the water. Harmful components in garbage are easily washed into the ground water body by rainwater, and a large number of acidic and alkaline organic pollutants will be generated during garbage stacking or pit filling, and heavy metals in garbage will be dissolved. The leachate produced by garbage pollution sources will enter the underground water body through soil infiltration; If garbage is directly thrown into rivers, lakes or oceans, it will cause more serious pollution. You see: plastic bottles and lunch boxes floating on the surface of the Summer Palace and Beihai, plastic bags and bread paper hanging from branches scattered on Xiangshan and Badachu forest mountain roads, and some tourists only seek their own convenience, which causes environmental pollution. If animals eat white garbage by mistake, it will not only hurt their health, but even lead to death.
fourthly, soil muck. The application of garbage directly to farmland or only after simple treatment will destroy the aggregate structure, physical and chemical properties and the ability of water and fertilizer conservation of soil. Especially plastic bags and sheets, if buried in farmland, the roots of crops will not grow, the farmland will reduce production, and the food available for people will decrease.
fifth, fire hazards. Garbage contains a lot of combustible materials, which will produce combustible gas such as methane in the process of natural stacking, and it is easy to cause fire when it meets open fire or spontaneous combustion. With the increase of organic matter content in municipal solid waste and the change from scattered storage in the open air to centralized storage, the harm of biogas produced by garbage is becoming more and more prominent in long-term storage, and garbage explosion accidents continue to occur, causing great losses.
sixth, the nest of pests. Garbage not only contains pathogenic microorganisms, but also provides food, habitat and breeding places for mice, birds and mosquitoes and flies, and is also the root of infectious diseases.
to sum up, the seriousness and urgency of the urban garbage problem are obvious. In order to turn these wastes into valuables, it is necessary to recycle and utilize them. Do you know? Recycling 1 tons of waste paper can produce 811 kilograms of good paper, cut down 17 trees less, save more than half of paper-making energy and reduce water pollution by 35%; 1 tons of waste plastics can recycle at least 611 kilograms of gasoline and diesel; Using waste glass to rebuild glass can not only save quartz sand, soda ash and other raw materials, but also save electricity; Smelting metal with scrap metal can save a lot of energy consumption and reduce air pollution; Some kitchen wastes such as peels, eggshells, vegetable leaves and leftovers can be treated by composting and fermentation to become green fertilizers.
Therefore, we should vigorously carry out publicity and education on classified collection of garbage sources through various mass media such as television, radio, newspapers and information networks. Pay close attention to the formulation of laws and regulations suitable for the national conditions on the classified collection and treatment of garbage, and strictly implement them; It may be considered to carry out the pilot work of classified collection of garbage sources in some units in depth and in detail; And further discuss with you to improve the management methods so that the classified collection of garbage sources can be carried out as soon as possible. Let's work together, with little effort, to promote classified recycling of garbage, eliminate garbage pollution, turn waste into treasure and save resources. So that Beijing can win the right to host the 2118 Olympic Games with a brand-new look, and at the same time provide ourselves with a beautiful and healthy living space.
As a new material with light weight, waterproof and corrosion resistance, plastic products are widely used all over the world.
Plastic was first used in agricultural plastic film, which brought great development to agricultural production, enabled crops to grow in any season and promoted market consumption. According to market statistics, from 1991 to 1995, the production of plastics increased at an annual rate of 8.9%, which has swept the whole earth. It can be called the "white revolution". But while it provides convenience for people, it also brings people a "white disaster".
Up to now, "white pollution" has become a well-known new term. It mainly refers to all kinds of foamed plastic bags, agricultural plastic films, etc., which have caused pollution to the environment and attracted widespread attention from the society.
Taiwan Province province of China issued a ban on "white products" in 1994, and a year later, the ban was cancelled.
As early as 1995, Hangzhou issued a notice prohibiting the local use of disposable foamed plastic tableware.
Guangzhou issued a government decree in June, 1997, stipulating that the production, sale and use of disposable non-degradable plastic lunch boxes were prohibited in the city from September 1st of that year.
based on this, in October, 1999, the State Economic and Trade Commission promulgated Order No.6 of 1999, which made it clear that disposable foamed plastic tableware, as an outdated product, should be completely eliminated before the end of 2111, and the production, sale and use should be completely banned from 2111.
From the above materials, it can be seen that more than a year has passed since the deadline, but disposable foamed tableware can still be seen everywhere. At that time, the government has changed its attitude from "banning white" to "ambiguous", often perfunctory, and the "banning white" has become a dead letter.
in view of the above situation, we have carried out various investigations and studies, consulted various materials, and obtained various aspects of various new substitutes developed and put on the market in China so far, and analyzed and summarized them.
hard journey we went to xigu district environmental protection bureau, where we were warmly received. during the conversation, we realized the true composition of "white pollution", got a preliminary understanding of the concept of "white pollution" and got some understanding of the current plan to control "white pollution" (with a question and answer record). We went to Xinhua Bookstore, provincial library and school stacks, but there was very little information about "white pollution", only the components of polyethylene, polypropylene and polyvinyl chloride, and the research process was blocked. In order to get rid of difficulties, we decided to use today's information technology-surfing the Internet. We found a vast space on the Internet, which made us have a deeper understanding of "white pollution". And it has greatly helped us to write the paper. With the above foundation, we decided to further understand the "white pollution" in Lanzhou. We have interviewed Hualian Supermarket, Electric Supermarket, and some retail stores and vendors. We are deeply shocked that so many plastic belts and foam lunch boxes are thrown away at will every day and every year, and people turn a blind eye to all this. We feel that it is too difficult to solve the problem of "white pollution" without improving the quality of residents. (A survey form is available)
"White pollutants" have such a strong vitality, and what kind of serious harm it will bring to our lives will be described in the following contents. First, let's know the composition of plastics.
1. Components of "white pollutants"
"white pollution" mainly refers to the pollution caused by white foamed plastic lunch boxes, various plastic bags and agricultural mulch to the environment. But "white pollution" is not what people usually think of as plastic products. As we all know, plastic is a new material with excellent comprehensive properties, and it is also a consumer product. Generally speaking, it is also a substance. Any substance has its life cycle, and the whole process of reaching the end of its life cycle is the degradation process. Therefore, plastic itself is degradable. It is only because of the stabilization technology, that is, adding light and heat stabilizers, antioxidants and so on to delay or inhibit its inherent biodegradability. Moreover, there are more than 311 kinds of plastics, and more than 41 kinds are commonly used, but only a small part of them can actually become white pollution. Therefore, "white pollution" cannot be equated with plastics.
The main components of "white pollution" are polyethylene (PE), polyvinyl chloride (PV), polypropylene (PP) and
polystyrene resin (PS). Let's make an understanding one by one:
Polyethylene:
Polyethylene is a thermoplastic resin prepared 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 a slightly white particle or powder, translucent, non-toxic, tasteless, good chemical stability, acid and alkali corrosion resistance. Commercially, polyethylene is classified into low, medium and high density. Generally, low density (1.92g/cm3-1.93g/cm3)
polypropylene:
without plasticizer is used for packaging, and its relative molecular weight is between 81,111 and 211,111. 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 (1.91 g/cm3-1.91 g/cm3), higher mechanical strength than polyethylene and good heat resistance. Among the three kinds of polypropylene, isotactic polypropylene has the largest output. Using titanium trichloride-diethyl aluminum chloride as catalyst, propylene was polymerized in hydrogenated gasoline to obtain isotactic polypropylene.
PVC:
The relative molecular weight is 51,121,111, and PVC is a thermoplastic resin, which is produced by free radical addition polymerization. Amorphous white powder with no fixed melting point and density of (1.35g/cm3-1.45g/cm3) has good chemical stability. Dissolved in cyclic ethyl ketone, chlorobenzene, dimethylformamide, toluene-acetone mixed solvent, etc.
polystyrene:
The average relative molecular weight is about 211,111. Colorless and odorless transparent resin with good light transmittance. The surface is glossy, flammable, and the density is (1.15g/cm3-1.17g/cm3). It has excellent water resistance, corrosion resistance and electrical insulation.
Production methods: bulk polymerization, suspension polymerization and emulsion polymerization. The bulk polymerization is introduced here. Initiator and a small amount of additives are added to styrene monomer, and then low-temperature polymerization is carried out in a prepolymerization kettle to prepare prepolymer, and then the prepolymer is transferred to a polymerization tower for high-temperature heating, and a certain temperature is maintained in stages. After the reaction, molten polystyrene is extruded into strips, cooled and hardened in water, and then diced and packaged.
The above are the main components of "white pollution". In addition, plasticizing agents, foaming agents, heat stabilizers and antioxidants are added to these pollutants.
2. The main causes of white pollution are extremely harmful:
1. The main reasons are: plastic garbage has not been properly managed and disposed of, garbage has not been collected separately, and it can be recycled
, and the final disposal method of garbage basically stops at the level of bare stacking or shallow burial. Some towns regard rivers, rivers and lakes as natural garbage dumps. Transportation and tourism, except railways, have not yet established a garbage collection system that is compatible with production and operation, leaving the garbage produced in the course of operation to its own devices. Weak management? There is a lack of relevant laws and regulations on plastic packaging waste and people's awareness of the environment is relatively weak; It is quite common to cause abuse and random dumping, which is not the responsibility of plastic products themselves.
2. major hazards:
"white pollution" mainly refers to two negative
effects of "visual pollution" and "potential hazards" on the environment.
"visual pollution" refers to the destruction of the city appearance and landscape by plastic waste scattered in cities. For example, a large number of polystyrene foamed plastic tableware scattered on both sides of railways, rivers and lakes and ultra-thin plastic bags flying all over the sky or hanging on branches have brought people bad visual stimulation, and people have strongly reacted to this.
"potential crisis" refers to the environmental problems caused by plastic waste entering the natural environment and being difficult to degrade.
Its harm mainly includes the following points: it is not easy to recycle, because the cost of recycling is high, but the utilization rate is low, so it can be said that businesses are unprofitable
, and it is difficult to attract the general public to carry out "white recycling" because of its low recycling price.
therefore, it is difficult to recycle. -Difficult to degrade. The recovered white waste is not easy to treat. At present, the main treatment methods are burning < P > burning and landfill. If it is burned, it will produce large