Recycling promotes the harmony of plastic packaging materials and the environment (3)

4 Simple evaluation of waste disposal methods for plastic packaging

4.1 Landfill treatment

For MSW treatment, landfill treatment is a relatively long-term, relatively simple technology and relatively economical method. However, this law occupies a limited amount of land resources on the earth. In addition, because of the poor facilities in ordinary landfills, exudates in landfills can contaminate groundwater sources, and the methane gas that escapes can pollute the air and are prone to explosion. As a result, it has received local governments in recent years. The crackdown of departments and local residents opposed; and the modern sanitary landfill has increased investment in landfills due to the addition of anti-seepage linings, exudate drainage devices, and methane drainage devices, and the landfill disposal fees. It also rose sharply. Therefore, although the amount of MSW in the world has been increasing in recent years, landfills have drastically decreased. In the future, this trend will continue, and most of the plastic wastes have been treated with landfills in the past. However, due to their light weight, large size, and good stability, long-term landfills are buried underground, and they are not easily decomposed. Substantially become garbage that has been buried underground for a long time. It does not solve the problem of polluting resources. Instead, it wastes valuable raw material resources and energy in a large amount of plastic waste. Therefore, disposal of plastic waste by landfill methods is considered unwise. Choice, and increasingly restricted.

4.2 Incineration treatment

Incineration treatment is an effective method for European countries to deal with MSW. Its main purpose is to eliminate waste. Because plastics generate a large amount of heat, and some plastics, such as PVC, generate harmful gases when incinerated, they can easily damage the furnace body and pollute the environment. In addition, the incinerator equipment investment is large and the processing cost is high. It is reported that the cost of incineration treatment per ton of MSW in Germany is 53. Dollars. Therefore, as a simple incineration treatment has been gradually limited. As the energy value of plastics in MSW is the highest and the average energy per kilogram is 4400 to 11000 kcal, it is increasingly regarded as a heat energy recovery and utilization. Some countries in Japan and Europe mainly generate electricity through incineration. Belgium and other countries incinerate and supply industrial steam. In addition to being used as heat energy, Japan also uses it as a solid fuel for ironmaking. They believe that the recovery of heat energy from incineration is a recycling of plastic waste. The important means are also the most realistic choices handled by MSW. In the United States, incineration treatment has long been opposed by the environmental protection agencies, and it is believed that the gas emitted by burning is harmful to national health, and it is considered that incineration treatment is still a wasteful use of available resources in the long run. In addition, because of the gas separation equipment necessary for incinerators, the investment in acid removal equipment is high, and the disposal of the remaining ash will increase the cost of incineration, resulting in a high cost of incineration and recovery of heat energy. Therefore, the proportion of incineration in the United States is far lower than in Western Europe and Japan. a lot of. However, in the past decade, the United States has also attached great importance to the recovery of thermal energy from incineration.

4.3 Recycling

The recycling of plastic packaging waste is considered to be a good way to better control environmental pollution, effectively use resources, and save energy. According to data reports, compared with new raw material products, plastic waste recyclable products can save 85 to 90% of resin production energy and save 6 to 17% of processing energy. However, due to historical conditions and technical and economic factors, the share of recycling in MSW processing to date remains low. The main problem is that a reliable and effective recycling channel has not yet been formed; the second is that MSW plastics are too dispersed and the components are mixed. It is difficult to separate and sort the technologies. Third, the recycling costs are high. It is reported that the German plastic waste recycling costs US$340 per ton. , Sort 528 US dollars, wash 400 US dollars. In addition, there are certain problems in the product direction and value of recycled materials, resulting in a low proportion of recycling. Although the recycling method has many technical and economic problems, it is not only beneficial to the protection of the environment, but also has great significance from the perspective of saving the limited resources on the earth and effectively utilizing renewable resources. Especially in the 21st century, human beings are faced with severe challenges in terms of resources, energy, and the environment. To get rid of the plight of resource scarcity, energy crisis, and environmental pollution, people are increasingly recognizing that the recycling of plastic waste is not only To come to economic benefits, but more importantly, social and environmental benefits. Therefore, the direction of disposal of plastic waste has gradually shifted to the development and utilization of renewable resources and secondary resources. Advances in science and technology have also created conditions for recycling. At present, many countries are gradually establishing a complete set of management systems for recycling, legislation, recycling, production, inspection, sales, etc., and research and develop a variety of recycling technologies, recycling and recycling technologies, recycling and recycling technologies, pyrolysis technologies, and oils. Technology, incineration and recovery of thermal energy technologies, and composting technologies are in the ascendant. Recycling has become an imperative trend in the plastics industry. According to relevant experts' prediction, the proportion of plastic waste recycling in the 21st century will increase to over 40% in plastic waste disposal, of which recycling and recycling will account for 42%, incineration and recycling energy will account for 26%, and pyrolysis And oil recovery chemicals and fuel oil accounted for 25%, other 4%.

4.4 Composting Technology

Composting, though old, traditionally adopts a method of treating domestic waste. However, with the advancement of technology and the development of biodegradable plastics, it has only recently begun to be approved by European and American countries for the feasibility of large-scale MSW. A directive European approach to composting as a way to recycle packaging materials by reusing organic waste to improve soils and establishing the ORCA (Organic Recycling and Composting Association) in Europe In the name of the government and legislative authorities, the paper on composting was published, stating that MSW composting could not only be used as a remedy for the soil being threatened, but also help to prevent the gradual decline of soil quality in continental Europe. Germany, Britain and France have begun to use compost as a means of recycling under the guidance of new regulations on waste disposal. According to a report released in the past few years by the Frankfurt School in Germany, there are about 15 cities in Germany currently adopting a composting method to process the organic components in MSW. Germany is widely promoting the use of composting systems and recommending the composting of biodegradable packaging materials. It should be regarded as equivalent to their recycling, which will make it easier for the national recycling industry to meet the recycling targets set by the packaging industry. France has more than 100 sets of composting equipment. These devices can process 1800 kt of household mixed waste each year, which can produce 700 kt of compost products. At present, the composting technology is gradually being put into practical use, and the composting equipment and sorting and processing technologies have been further improved. The corresponding quality standards have been established through the appraisal and monitoring systems. Therefore, it is considered as a development method with potential for development.

4.5 Degradable Plastics

The research and development of degradable plastics can be traced back to the 1970s. At that time in the United States, the use of plastic beverage bottles to lift rings and discarded fields after the use of agricultural films not only affected the appearance of the environment, but also endangered the life of wild animals, and were thus condemned and crusade by the environmental protection department. . For this reason, research on photodegradable plastics was carried out. In the 1980s, starch-filled “biodegradable plastics” were researched and developed, and they were blown up to be rapidly biodegradable under the influence of microorganisms in landfills or soils. The market was all the rage, but after years of practice, this material has been accused of exaggerating propaganda, false propaganda, and strong opposition from the environmental protection department for failing to obtain a convincing biodegradable effect. Degradable plastic technology has made great progress since the 1990s, and developed many new varieties such as light/biodegradable plastics, photothermal degradable plastics, starch blended degradable plastics, water-soluble degradable plastics, and completely biodegradable plastics. Since entering the 21st century, biodegradable plastics, especially biomass plastics, have met the principles of environmental protection and sustainable development and have received greater attention and further development.

Although the degradable plastics have made great progress, in general, the degradable plastics technology needs to be further improved and perfected. The performance needs to be further improved and the cost needs to be further reduced. Its role in the environment should be properly evaluated.

Degradable plastic is a member of the plastics family. It is required to maintain or have the characteristics of ordinary plastics before use, and after use, it requires rapid degradation under natural environmental conditions. Stability and degradation are a contradiction. It is achieved at different stages of the same product, and it is very difficult and it is a high-tech product.

Degradable plastic Because it has the function of easy degradation, it is only suitable for specific application fields and certain plastic products, such as disposable packaging materials, plastic film, medical and health materials, etc. These products are seriously polluted and difficult to recycle or even collect value of use. Small, little or no benefit, so the use of degradable plastics can make waste volume reduction, so as to achieve the purpose of reducing environmental pollution.

• Some of the degradable plastics currently entering the market are disintegratively degradable, and they cannot be quickly degraded and completely degraded, but they can be degraded and disintegrated into fragments that are easily consumed by the environment under certain environmental conditions and within a certain period of time. With time, it will eventually enter the natural world. Fully biodegradable plastics can be decomposed into CO2 and water faster and more completely under certain environmental conditions. Combined with composting treatment methods, they are complementary to recycling and are considered to be good for the pollution of plastic packaging waste. The measures are the current direction of international development.

·Research and development and application of biodegradable plastics, whether from the actual perspective of global environmental protection or the gradual replacement of inexhaustible renewable resources gradually reduced, and non-renewable petrochemical resources and the strategic height from the implementation of sustainable development All have important significance.