How do fruit peels and leaves classify garbage?

White pollution is a unique environmental pollution in China. 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 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, plastic products should be recycled as much as possible, because the main source is exhausted oil 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. Facing the increasingly serious problem of white pollution, people hope to find a plastic substitute, which can replace the existing plastic properties without causing white pollution. Degradable plastics came into being. The characteristic of this new functional plastic is that after reaching a certain service life, its chemical structure will degrade obviously under certain environmental conditions, 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, which leads to the decline of the mechanical properties of the film. At the same time, the self-oxidant added in the formula reacts with the metal salt in the soil to generate peroxide, which breaks the chain of polyethylene and degrades it into small pieces that are easily swallowed by microorganisms, which are absorbed by the natural environment and play a role in improving the soil.

Domestic waste refers to solid waste generated in daily life or activities providing services for daily life, and solid waste regarded as domestic waste according to laws and administrative regulations.

Garbage classification refers to the classification of garbage into different categories according to its different components, attributes, utilization value and impact on the environment, and according to the requirements of different disposal methods.

Domestic garbage can generally be divided into four categories: recyclable garbage, kitchen garbage, harmful waste and other garbage. At present, the commonly used garbage disposal methods mainly include comprehensive utilization, sanitary landfill, incineration and composting.

Recyclable garbage includes paper, metal, plastic, glass, etc. Through comprehensive treatment and recycling, pollution can be reduced and resources can be saved. If every 1 ton of waste paper is recycled, 850 kilograms of paper can be made, 300 kilograms of wood can be saved, and pollution is reduced by 74% compared with the same output; Every 1 ton plastic beverage bottle can recover 0.7 tons of secondary raw materials; Every recovered 1 ton of scrap steel can produce 0.9 tons of steel, which saves 47% of the cost compared with ore smelting, reduces air pollution by 75%, and reduces water pollution and solid waste by 97%.

Kitchen waste includes food waste such as leftovers, bones, vegetable roots and leaves. After in-situ composting by biotechnology, 0.3 tons of organic fertilizer can be produced per ton.

Hazardous wastes include waste batteries, waste fluorescent tubes, waste water silver thermometers, expired drugs, etc. These wastes need special safety treatment.

Other wastes include bricks and tiles, waste residue, toilet waste paper and other wastes that are difficult to recycle. Sanitary landfill can effectively reduce the pollution of groundwater, surface water, soil and air.

Classification of medical wastes.

Disposable medical devices after use, whether the needles are cut or not, and whether they are contaminated by body fluids, blood and excreta of patients, are all medical wastes and should be managed as medical wastes.

All kinds of glass (disposable plastic) infusion bottles (bags) that are not contaminated by patients' blood, body fluids and excreta after use are not medical wastes and need not be managed according to medical wastes. However, this kind of waste cannot be used for its original purpose when it is recycled, and should be used for other purposes according to the principle of not endangering human health. The ball is our home and provides us with such a beautiful environment. However, with the rapid development of social economy and the high concentration of urban population, the output of domestic garbage has gradually increased, and our home is surrounded by garbage.

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 occupies a lot of farmland. Garbage stays in nature for a long time: cigarette butts and woolen goods 1-5 years; Orange peel for 2 years; Can be 80- 100 years; Plastics 100-200 years; Glass 1000.

Second, pollute the air. Garbage is a complex mixture. In the process of transportation and open-air stacking, the decomposition of organic matter produces stench, which releases a lot of pollutants such as ammonia and sulfide into the atmosphere, including 100 kinds of volatile organic gases, which contain many carcinogens and teratogens. Plastic film, paper scraps and dust fly with the wind, forming "white pollution".

Third, pollute the water source. Harmful components in garbage are easily washed into underground water by rainwater, and a large number of acidic and alkaline organic pollutants will be produced during garbage stacking or pit filling, and heavy metals in garbage will be dissolved. If garbage is directly thrown into rivers, lakes or oceans, it will cause more serious pollution. Look: plastic bottles and lunch boxes floating on the surface of Qinhuai River, plastic bags and bread paper hanging on the branches. Not only causes environmental pollution. And if animals eat white garbage by mistake, it will not only harm health, but even die.

Fourth, fire hazards. Garbage contains a lot of combustible substances, which will produce methane and other combustible gases during natural stacking. In case of open fire or spontaneous combustion, it is easy to cause fire and garbage explosion accidents, causing heavy losses.

Fifth, 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.

As a serious environmental problem, municipal solid waste has been placed in front of city managers. In 2000, the rough statistics of domestic garbage removal in 668 large and medium-sized cities in China have exceeded 654.38+0.5 billion tons. Due to the limitation of funds and technology, most of the domestic garbage has not been treated in time and effectively, and many cities have been surrounded by garbage, which has become a very headache for city managers. The author believes that the treatment of domestic waste should also adhere to the principle of sustainable development, implement maximum reduction, and then implement resource utilization and industrialization. The feasibility, social benefits and specific operations of domestic waste reduction are discussed below.

1 Feasibility of reduction

At present, sanitary landfill is the most common way to treat domestic waste in China. Most of these domestic wastes are not classified. Among them, there are some toxic substances, such as used batteries and used electrical appliances (such substances are hazardous wastes and the state explicitly prohibits landfill treatment). There are many recyclable materials, such as waste paper, metal, glass and so on. The direct landfill of these wastes without treatment will not only cause serious pollution, but also waste some available resources.

Before the energy structure with coal as the main domestic energy source has been adjusted, the domestic garbage in small and medium-sized cities can be reduced first and then treated. Therefore, the author conducted a field survey in a boarding school and a residential area in Changsha. The school covers an area of about 15 1 800m2, with students 1300 and 400 staff and their families. The residential area is about 20 000m2, with 1 12 households and a population of about 400 people.

Table 1 is the composition and content of domestic waste obtained by the author after a field investigation in a school and a community for a period of 1 week (7 days); Table 2 shows the composition and content of municipal solid waste in Changsha and Chenzhou. Table 3 shows the composition and content of domestic waste in public sectors and Heping District (1995) in Beijing.

Position waste paper metal plastic glass humus grey battery leather fabric

School/%2.890.42 7.40080.80080808885

Residential area/) .854.05438+017.545.091.81.5.7802 (32 branches) 1.754.5438+05.

Located in a residential area in Changsha, the property management is completely closed, no other scavengers enter the residential area, and there are no coal-burning households, which belongs to the above-average living standard. During the investigation, with the assistance of the property management company, three cleaners are arranged every day to weigh and fill the paper, metallic glass, plastic, humus, battery, leather, cloth, muck and other forms in the garbage bin at each entrance. In the tree-lined area of the school area, a large number of fallen leaves and weeds pulled out every day are classified as humus. The school boiler supplies the steam for steaming rice in the student canteen and the boiling water and hot water for students, but it does not include the slag generated by the boiler. If the boiler slag is included, the statistical data of each component will become:

Position waste paper metal plastic glass humus grey battery leather fabric

School/%1.760.264.770.3919.7972.180.0360.82

Residential area/) .854.05438+017.545.096438+0.815.7802 (32 branches) +0.754.5438+05.

Table 2 Composition and content of domestic waste in Changsha and Chenzhou

Regional flora and fauna, furnace ash, slag, stone, paper, plastic, glass, metal cloth, bamboo and wood.

Changsha (1995) 0.22 ~1.305.67 ~ 20.3755438+0.55 ~ 69.9418.56 ~ 20.570.50 ~1.780.

Chenzhou (2001) 9.78.9558.52.84.51.21.26.41.8

Table 3 Composition and Content of Domestic Waste in Beijing Business District and Heping Community (1995)

Location: lime soil, food, paper, brick, plastic, vegetation, glass fiber, metal.

Business area 4.4529.3412.78 3.271.1122.911.203.

Bungalow area 22.4042.796.522.338+010.493.672+060.50089.00000000066

According to the classification survey of domestic waste, the content characteristics of each component are as follows: the content of various available waste paper, metals and plastics (including beverage bottles, etc.). ), leather and so on. All of them were left after rough selection by health and cleaning personnel, but they are generally similar to the statistical data of domestic waste in Changsha, Chenzhou and other areas. If the available substances in the current domestic garbage are further classified and recycled, the weight of the garbage will be directly reduced by 25.74%, and humus (mainly composed of leaves, weeds, vegetable leaves, peels, discarded food, etc.). ) will be classified, collected and concentrated, which will not only become a good fertilizer, but also reduce the weight of domestic garbage by about 50%. From this point of view, it is feasible to reduce domestic waste.

Of course, there are many ways to reduce the amount of garbage, such as reducing the amount of garbage from the source, implementing clean vegetables into the city, slaughtering inedible vegetable roots, leaves and livestock in the rural areas outside the city for agricultural fertilizer use, and cleaning vegetables into ordinary families will also reduce humus. The content of paper and other substances will increase, so that more and more components can be used in domestic garbage, and less and less garbage needs to be landfilled. The relevant departments of our government have made some specific provisions on this, and many cities are also carrying out this work and have achieved certain results. With the improvement of urban residents' living standard, the change of residents' fuel structure and the improvement of living fuel mode, liquefied petroleum gas, gas and natural gas will gradually replace coal, and the output of ash will drop sharply, which has obvious effect on waste reduction.

2 the benefits of reduction

The benefits of landfill after waste reduction can be calculated from two aspects.

The first is indirect income. Building a landfill requires a large area of open space, and the service life of a landfill that costs tens of millions or even hundreds of millions of yuan is limited. For example, Changsha 1998 invested 66.2 million yuan to build a new landfill with an area of 792 000m2 and a volume of 50 million m3, with an estimated service life of 60 years. The landfill site with an investment of19.44 million yuan in Chenzhou started construction in August 2002 and is expected to be completed by the end of August 2003. Covering an area of 98,000m2, it receives domestic garbage1640,000 tons every year, and its expected service life is LL ~ 12 years. At the same time, the location of the new landfill is 7 kilometers away from the urban area as required, so it is increasingly difficult to find a place around the city that meets this condition. Landfill treatment after the reduction of domestic waste can prolong the service time of landfill, indirectly reduce the annual cost of landfill and improve economic benefits.

The second is to benefit directly. As far as the composition of domestic waste is concerned, if waste paper is 0. 15 yuan/kg, metal is 0.25 yuan/kg, glass is 0. 15 yuan/kg, plastic is 0. 15 yuan/kg, and beverage bottles are 0.05 yuan/bottle, the monthly resident population is less than/kloc-. According to relevant data (Beijing Daily, June 5438+1October 13), the garbage army of 82,000 people in Beijing collected 3.5 million tons of garbage from the source, with a total income of 930 million yuan. In that year, only 2.7 million tons of garbage were removed by the Environmental Sanitation Bureau of the Eighth District of Beijing, and the municipal government spent 750 million yuan to dispose of the garbage. Therefore, the implementation of waste reduction can not only increase employment opportunities, improve the income of relevant personnel, but also reduce government financial expenditure.

3 reduction of ordered operation

The key to implement waste reduction is to classify waste, which is not only the work of environmental protection and sanitation departments, but also involves the comprehensive management of a community and a city. It needs the cooperation of many departments in the community and the city and all citizens. Domestic waste sorting is an orderly and purposeful activity, which requires a large number of specially trained cleaning staff to collect and sort, and at the same time, it also solves the re-employment problem of a group of surplus labor.

First, the present situation and utilization of urban garbage disposal industry.

(1) Municipal solid waste and its treatment status

At present, the daily output of municipal solid waste is 837 tons (calculated by actual tonnage), and the annual output is 305,500 tons. With the continuous growth of urban population, the output of municipal solid waste is steadily increasing. All domestic wastes are centrally treated by Chengnan Domestic Waste Sanitary Landfill and Xishi Garbage Harmless Treatment Plant, of which Chengnan Plant has a sanitary landfill capacity of 230,000 tons and Xishi Plant has a composting capacity of about 70,000 tons.

At this stage, the urban garbage treatment measures are as follows:

1. In order to further control the phenomenon of "littering", the Nanning Municipal Government issued a notice, adopting a management mode of combining education with punishment, and imposing the highest fine on individuals who litter. According to the circular, those who throw chewing gum, melon and fruit peels, cigarette butts, food packaging and other wastes will be fined between 65,438 yuan and 65,438 yuan in 50 yuan; Spitting, urinating, throwing objects or splashing water inside and outside buildings and car bodies shall be fined from 50 yuan to 200 yuan; Dumping, spilling or piling up construction waste at will, the unit shall be fined between 5,000 yuan and 50,000 yuan, and the individual shall be fined between 200 yuan.

The medical waste in seven counties under the jurisdiction of this city has a unified "destination". In order to reduce the pollution of medical wastes, all medical wastes in six counties will be concentrated in special waste treatment limited liability company for unified disposal.

2. Citizens should pay for the domestic garbage. The Municipal People's Government began to collect the municipal solid waste disposal fee from July, 2003 10, exempting retirees and halving the collection for vulnerable groups such as residents who enjoy the minimum living guarantee. The specific collection standards of domestic waste (including construction waste and muck, excluding industrial solid waste and hazardous waste) are as follows: urban residents (villages) collect it by households, and each household will have a monthly 7 yuan before July 10, 2005 (combined with the current garbage removal fee); The temporary population in the city is charged per person, and before July 2005 10, 2 yuan per person per month; State organs, institutions, social organizations and other institutions are charged according to 2.5 yuan/person/month; The catering and entertainment industry is charged according to 3.3 yuan/Luo/time (25 Jin per Luo); Market stalls charge from 1.3 yuan to 1.8 yuan/booth/day; Hotels, restaurants and guest houses charge 2 yuan per bed per month according to the actual number of beds; Production and processing enterprises, according to 80 yuan/ton; Commercial outlets outside the catering and entertainment industry are charged according to the operating area; In the past, long-distance and short-distance passenger vehicles were charged according to the approved seat 1 yuan/seat/month; Units will be garbage removal to the garbage dump, according to the 50 yuan/ton charges; Construction waste is charged at 15.8 yuan/ton.

It is understood that more than 95% of domestic waste treatment is carried out in the southern domestic waste landfill in Liangqing District. The site was built in 1995, and has treated more than 3 million tons of domestic garbage so far, far exceeding the original design capacity. In 2004, Nanning Municipal Party Committee and Municipal Government listed the second phase expansion project of the site as a key project for private practical work. According to the introduction of relevant municipal departments, this expansion project plans to invest more than 200 million yuan, which is the largest domestic garbage dump in southwest China, with a service life of 2 1 year. In terms of environmental protection, the domestic advanced horizontal seepage control technology is adopted to treat leachate simultaneously to meet the high domestic standards; The comprehensive utilization rate is high, and the landfill construction is carried out simultaneously with the cdm project (comprehensive utilization of domestic waste gas treatment) introduced by foreign capital.

(2) The main problems existing in the treatment and the suggestions and countermeasures to solve them.

The main problem of municipal solid waste treatment is serious secondary pollution, and the discharged wastewater, waste gas and waste residue cause certain pollution to the external environment. Sanitary landfill, which accounts for a large proportion of garbage disposal, only transfers the generated domestic garbage from one place to another and treats all the garbage as waste. The utilization rate of garbage resources is zero, which does not meet the requirements of building a conservation-oriented society in China. Therefore, the secondary pollution caused by garbage disposal is shocking and more harmful than the garbage itself. Waste treatment plants using other methods are not running smoothly because of the high treatment cost and no market for products.

The change trend of calorific value of domestic waste is linear and gentle, which is inversely proportional to the change of water content of waste. There is still a certain gap between the low calorific value and the national requirements for waste incineration above 5000kj/kg. At the same time, due to the restriction of regional economy, domestic garbage can not be directly burned, and the content of nitrogen, phosphorus, potassium and organic matter in garbage is high, so the characteristics of garbage are still suitable for composting. In addition, the local demand for garbage compost products is still large, so it can be seen that in the future, sanitary landfill is the main treatment method of urban domestic garbage, supplemented by high-temperature composting, which is both practical and scientific.

However, due to the high operating cost of composting plants and the difficulty in selling fertilizers, the development of municipal solid waste composting methods in Nanning is not smooth. In recent years, due to the improvement of composting technology and the reduction of cost, composting has been re-listed as one of the important ways to recycle municipal solid waste in Nanning. To sum up, due to the simple recycling and low cost, and the limitations of incineration power generation and composting in terms of capital and technology, it is the best way to give priority to recycling and moderately develop composting treatment, which is in line with the development reality.

Second, the experience and enlightenment of garbage composting and multi-channel recycling in the United States

Composting municipal solid waste (MSW) was once the main garbage disposal method in the United States, and it was also one of the main measures to turn waste into treasure. Due to the quality of waste composting products, the operating funds of composting facilities and the expansion of composting products market, all large-scale mechanized waste composting plants in the United States were basically closed in the 1980s and 1990s, which made waste composting enter a trough. In recent years, with the United States paying more and more attention to the development and utilization of waste resources, waste compost has been widely used as an important part of waste resources, especially yard waste and kitchen waste compost, which has been widely used in the United States and has become one of the main measures for waste resource recovery and recycling. The United States produces an average of 26.29 million tons of kitchen waste every year, accounting for 1 1.4% of the total solid waste in the city. How to make good use of compost to treat kitchen waste and turn waste into treasure has been tried in many States in the United States, and the effect is obvious.

The implementation measures to realize multi-channel recycling in the United States mainly include:

1. Improve the design, manufacture and packaging of products. Actively use alternative materials for production, make products easy to recycle, simplify commodity packaging, and use easy-to-recycle materials for green packaging. In the United States, the laws of nearly half states prohibit the production and use of product packaging that cannot be decomposed, reduced or recycled.

2. Establish a roadside resource garbage sorting and recycling system. Since the end of 1980s, some cities have actively established a roadside resource waste sorting and recycling system, that is, residents are required to sort and concentrate their domestic waste and put it on the roadside for recycling by special personnel, so as to promote the reuse of resource waste. At present, 44 states have formulated laws and regulations on classified recycling.

3. Implement various forms of recycling. In addition to roadside recycling, the United States has also established other forms of municipal solid waste recycling, such as the recycling method of dropping centers, the recycling method of commercial outlets and the recycling method of large containers on the streets. By setting large sorting containers in densely populated areas, it is convenient for people to put in resource garbage.

The beneficial enlightenment of the recycling of municipal solid waste in the United States is that by formulating laws and regulations and policies for recycling of municipal solid waste led by relevant government departments, the enthusiasm of enterprises and residents to participate and support can be stimulated, so as to accelerate the recycling of municipal solid waste and finally realize the harmony between urban development and ecological environment.

Third, the countermeasures and suggestions for the development of municipal solid waste resource industry

No matter from the scarcity of resources or from the effective experience of foreign countries, the gradual development of urban solid waste recycling industry is not only to alleviate the shortage of urban resources, but also to implement the goal of Scientific Outlook on Development and achieve sustainable economic development.

(A) to strengthen the classification and recycling of municipal solid waste.

Classified recovery of municipal solid waste is an important prerequisite to realize the recycling of municipal solid waste. In order to promote the classified recycling of garbage, garbage containers with different signs should be placed in residential areas, businesses, cultural and entertainment centers. At the same time, formulate corresponding punishment systems and measures to ensure that residents consciously put garbage into categories and realize classified collection of garbage. If garbage can't be collected or classified separately, the useful resources in garbage can't be recycled. Developed countries have their own effective methods and systems in the field of classified recycling. Their experience shows that garbage sorting and collection can get twice the result with half the effort. Therefore, it is necessary to establish a garbage sorting and recycling system.

(two) gradually improve the city life garbage disposal fee system.

The key to perfecting the charging system of urban garbage disposal is to establish an effective operating mechanism in line with the market economy. In the second half of 2003, the urban garbage disposal fee began to be piloted, and it was gradually on the right track in 2004. Urban garbage disposal fees have been fully rolled out in the whole city, and breakthroughs have been made. In the whole year, * * * collected 23.723 million yuan for domestic garbage disposal. To some extent, this provides a certain financial guarantee for the effective operation of urban garbage disposal enterprises. Although the cost itself is not directly related to the environmental impact, through this economic stimulus, garbage producers can bear part of the external environmental costs, increase the funds for recycling urban garbage, improve the environmental awareness of urban residents, and force them to reduce the amount of urban domestic garbage through recycling and promote the recycling of urban domestic garbage.

(C) the realization of industrial management of municipal solid waste treatment

Industrialization of municipal solid waste treatment can achieve economic, environmental and social benefits. To realize the industrialization of municipal solid waste treatment, the government should start from the following aspects:

1. Diversification of business entities. As far as the current situation of urban garbage disposal is concerned, it is not possible to achieve complete marketization. Therefore, we can only implement a semi-market and semi-social management model. Change the past situation of complete control and single operation by the government, and realize diversification of handling. It can be invested by the government and entrusted to a specialized operation company for operation after completion. To realize the industrialization of municipal solid waste, we must follow the laws of market economy, and on the basis of ensuring social benefits, constantly broaden channels and realize industrial management.

2. Encourage innovative research and development of garbage disposal technology, improve technical content and develop circular economy.

On the premise of comprehensive utilization of municipal solid waste, through scientific and technological progress and innovation, we can fully rely on the market to realize large-scale production. Through the introduction of technology, digestion and absorption, scientific research institutions focus on supporting research and development, and so on, we will gradually form a sound scientific and technological system for recycling municipal solid waste, and promote the development of municipal solid waste recycling industry.

3. Introduce a competitive mechanism to gradually realize the market-oriented management of domestic waste.

Urban garbage disposal industry has become a sunrise industry in many developed countries, and many entrepreneurs have taken a fancy to this opportunity and gained a lot of benefits in this respect. In China, because the central government insists on Scientific Outlook on Development and vigorously develops circular economy, many enterprises have realized the potential economic benefits of municipal solid waste and used it as a recyclable resource. After a period of publicity, environmental protection industry has been paid more and more attention. The government should actively guide the economy to participate in the treatment of municipal solid waste, thus forming a competitive mechanism and promoting the market-oriented management of municipal solid waste.

4. Develop and cultivate the urban garbage disposal industry market.

Neither a single investment mechanism nor full government investment in China is a long-term solution. The government should pay special attention to the cultivation of technical product market, capital investment market and technical service market. The public should actively support the production and operation activities of municipal solid waste recycling enterprises and create a good policy environment and market space for the development and growth of enterprises.

References:

[1]. Liu Yong. Jun Lv. Study on the development of China municipal solid waste resource treatment industry under the background of urbanization. [j]。 Scientific and technological progress and countermeasures. 2007.3008+00.

[2]. Ray JIU. Chen peisheng Present situation and trend of municipal solid waste treatment in the United States. [j]。 Research and discussion. 2007+2008+0