With the development of society and the continuous improvement of economic level, people produce more and more domestic garbage, especially rural domestic garbage. It mainly includes batteries, light bulbs, pesticide bottles, paint buckets, waste water silver thermometers, expired drugs, ink cartridges, selenium drums, non-degradable plastic products (ultra-thin plastic bags, agricultural films) and so on. With the development of rural and urban-rural integration, the amount of this kind of garbage is increasing year by year. This kind of garbage has the greatest potential harm to the rural ecological environment and needs special safety treatment. For example, button cell contains toxic heavy metal mercury; Rechargeable batteries contain harmful heavy metal cadmium; Dry batteries contain mercury, lead, acid and alkali substances and other substances harmful to the environment. However, waste plastic products are difficult to decompose, destroying soil and reducing plant growth by 30%; Groundwater may be polluted after landfill; Incineration will produce harmful gases. How to treat rural domestic garbage to be truly harmless? What about the home where we live? We can't help worrying. Therefore, the first problem to be solved is to carry out popular science propaganda and enhance farmers' awareness of environmental protection. Because it is very important to shape the social participation consciousness of social individuals and even social organizations through effective environmental education. Doing a good job in rural domestic garbage disposal requires the active participation and cooperation of rural residents, and environmental protection departments, news media and teaching units need to go to the countryside to publicize and popularize environmental protection knowledge. We should be good at combining and using World Environment Day, Earth Day and National Patriotic Health Month. Hanging environmental protection propaganda slogans in public places, organizing cadres, the masses and students to carry out environmental sanitation cleaning, using radio, television and other media for publicity, holding mass environmental protection knowledge contests and other activities to attract the active participation of the general public and gradually improve residents' environmental awareness. The publicity and education of environmental awareness should start with the details that are closest to farmers' lives, so that environmental knowledge can be in "zero distance" contact with them in the form of small moves and tricks, so as to narrow the distance between knowledge and life, eliminate the plot of farmers' conflict and improve the publicity effect.
The treatment technology of "fast, harmless, non-surplus, resource-based and industrialized" is referred to as "LJ five-oriented" treatment technology. This craft set: 1
Uniform feeding of municipal garbage and automatic sorting system of large-particle garbage; 2
Bagged garbage automatic bag breaking and organic matter automatic crushing system; three
Fully enclosed mechanized sorting system for municipal solid waste; four
Organic hydrolysis water thermal oxidation fertilizer system; five
Inorganic building material system; five
Plastic refining or granulation system; six
Non-recoverable combustible pyrolysis gasification and waste heat utilization system; seven
Exhaust gas treatment system; eight
Eight treatment systems, such as sewage treatment system, are combined into one, which can treat municipal solid waste generated in various places on the same day and produce products on the same day. This technology has been successfully applied to waste treatment plants in Guangdong, Zhejiang, Yunnan, Guizhou, Hebei, Liaoning, Shanxi and other places, and has achieved obvious economic and social benefits in various places, realizing the recycling and industrialization of waste treatment to the maximum extent. Experts agree that this technology treats waste with waste, which meets the requirements of circular economy development and represents the development direction of garbage disposal in China.
2. Classification of rural domestic waste
There are four common methods to deal with rural domestic garbage.
1. thermophilic aerobic composting technology
Composting is a metabolic process of microbial degradation of organic matter in garbage, and the organic matter in garbage becomes stable organic residue after high temperature decomposition. Aerobic composting process usually includes pretreatment, main fermentation, post-fermentation, post-treatment and storage. When the organic matter content in garbage is more than 15%, composting can make garbage harmless and reduce it. Garbage compost can be used in agricultural production to increase soil organic matter content. Therefore, the recycling benefit of waste composting method is remarkable, but composting requires high organic matter content and low heavy metal content in waste.
2. Biomass gasification technology
This technology uses rich organic waste resources in rural areas, such as straw, firewood, chaff and other wastes, to generate combustible gas after pyrolysis at high temperature. It has many advantages, such as high energy conversion rate, low energy consumption, long combustion time, large and stable firepower, and no pollution in the combustion process. It can not only improve the rural production and living environment, but also save resources and energy. The organic waste purification furnace adopting this technology is convenient to use and low in cost, and has three functions of cooking, heating and showering.
3. Earthworm composting technology
The basic principle of earthworm composting technology is to make use of the characteristics of earthworm eating carrion, eating a wide range and eating a large amount. Its digestive tract can secrete protease, lipolytic enzyme, cellulolytic enzyme, chitinase, amylase and other enzymes, and feed the organic solid waste fermented to earthworm as food, which is transformed into feces with good physical, chemical and biological characteristics through digestion, metabolism and extrusion of earthworm digestive tract, so as to achieve the purpose of harmlessness, reduction and resource utilization.
4. Anaerobic fermentation technology
Anaerobic fermentation is an energy source that makes organic matter produce combustible gas-biogas through microbial fermentation in anaerobic environment, and converts organic matter into domestic fuel. At the same time, biogas and biogas residue are high-quality fertilizers. This method makes the organic matter fully resource. Fermentation raw materials are mainly human and animal feces. It has the advantages of recycling waste, convenient management, less investment, simple operation and so on, which is convenient for popularization and use in the vast rural areas.
3. Scientific knowledge in rural domestic waste treatment
The integrated technology project of harmless treatment of municipal solid waste is led by Guangzhou Institute of Energy, Chinese Academy of Sciences, and implemented by Chen Yong, the chief scientist. Chengdu Institute of Biology, Chinese Academy of Sciences completed the demonstration project of comprehensive utilization technology of municipal solid waste as resource and energy, which is one of the 100 scientific and technological innovation projects in Guangdong Province.
The demonstration project was built in Boluo County, Guangdong Province, with 100 projects specially supported as the starting capital, with a total investment of 22.85 million yuan. This is a 200-ton/day energy self-sufficient municipal solid waste comprehensive treatment and utilization system. The first phase of the project deals with 54,000 tons of domestic garbage every year, and produces 65,438 tons of organic compound fertilizer+8,000 tons. The problem of urban garbage disposal affects the national economy and people's livelihood, and the output of garbage increases sharply, which seriously harms the environment.
The annual storage of garbage in China is 6 billion tons, 1.997, and the annual output of garbage in China is1.40 billion tons, with an annual growth rate of 8- 10%. Up to now, the vast majority of municipal solid waste in China is still mainly piled and buried in the open air, which not only occupies valuable land resources, but also causes serious secondary pollution to the environment. It is imperative to study the comprehensive management technology.
On the one hand, the main obstacle to the resource utilization of garbage lies in the complex composition of garbage itself and the difficulty of resource utilization. On the other hand, the research and development of related technologies has not kept up. The existing utilization technology often adopts a single mode (such as incineration for power generation) to treat different garbage components in the same way, which leads to large consumption and poor economy in the treatment process itself.
Therefore, it is of great significance to study the key technologies of comprehensive treatment according to the different components of garbage according to local conditions, which is a major event related to the national economy and people's livelihood. The demonstration project is ingenious in conception and comprehensive in technology. Cities at home and abroad mainly adopt landfill, composting, incineration and other methods, among which landfill technology occupies a large area; Composting technology has the disadvantages of volume reduction, reduction and low degree of harmlessness; Using garbage incineration technology has a high degree of reduction, but the investment is huge.
Therefore, relying solely on a certain technology to deal with garbage is not the fundamental method to solve the garbage problem that is suitable for China's national conditions. According to the characteristics of municipal solid waste in China, and from the viewpoint that garbage is a kind of misplaced resource, this project has developed a new technology and process of garbage treatment and recycling with low investment, high treatment efficiency and low cost-energy self-sufficient municipal solid waste comprehensive treatment and utilization system.
According to the different components and physical and chemical properties of garbage in China, different garbage treatment technologies are organically combined to achieve the goal of reduction, reduction and harmlessness, and at the same time, the treatment cost is minimized and the garbage resources are comprehensively utilized as much as possible. On the basis of studying the composition of domestic waste in Boluo County, the researchers of this project put forward a system integration technology combining sorting, organic waste fermentation, fertilizer processing, combustible pyrolysis-incineration, gasification power generation and inorganic waste landfill: (1) sorting municipal domestic waste and recycling renewable materials, such as renewable plastics, metals, waste paper and glass; Combusting separated combustible materials; Fermenting the sorted perishable organic garbage, and making the treated organic garbage into organic fertilizer; Inorganic waste can be used for landfill, paving or soil improvement (fine inorganic waste).
(2) During the fermentation process, municipal organic waste can be harmlessly decomposed by microorganisms to produce organic fertilizer, which can provide organic fertilizer for agriculture. Rotten organic waste comes from spontaneous combustion and returns to nature, thus maintaining the ecology of nature. The process can adopt rapid aerobic fermentation and high temperature ripening, and the treatment period is 15 days.
The waste gas produced by closed fermentation is concentrated and discharged at a high level, and the exudate produced in the fermentation process is recycled without wastewater discharge. (3) Organic Waste Treatment and Fertilization Technology The way out for urban organic waste after treatment is to produce fertilizer. The fertilizer is sold smoothly and has a wide application range, which makes the garbage treatment go smoothly and will also obtain certain economic benefits.
In terms of product quality, besides the quality of compost, the treatment of organic waste is also very important. The treated organic waste is processed into fine powder fertilizer by secondary screening, making coarse compost or drying, which can be used in paddy field, dry land and various crops.
In addition, it can also be made into organic-inorganic compound fertilizer, which not only has obvious yield increase effect, but also can improve the utilization rate of chemical fertilizer. (4) Incineration technology has the characteristics of rapid reduction and is suitable for the treatment of combustible organic wastes. This treatment technology uses combustible organic matter separated in the separation process for incineration.
Because the garbage used for incineration has low moisture content and high calorific value, there is no need to increase auxiliary combustion during incineration, and the generated heat energy is used for fertilizer making and drying, which can save energy. The process adopts pyrolysis and incineration technology to reduce the volume and quantity of combustible organic waste.
Pyrolysis incineration is an advanced incineration technology developed internationally. This technology takes advantage of the high volatility of organic matter in garbage. First, the garbage is pyrolyzed (or gasified), and then the volatiles are released for gas phase combustion.
Through pyrolysis, gasification and incineration, dust, NOX, SOX and HCl in flue gas are removed and washed to ensure that the tail gas reaches the standard. (5) The gasification power generation technology adopts the waste gasification-internal combustion engine power generation technology of Guangzhou Institute of Energy, Chinese Academy of Sciences, and the principle is the same as pyrolysis (gasification) incineration.
Combustible gas burns at high temperature in internal combustion engine, which can completely burn harmful macromolecular organic substances and generate small molecular harmless substances such as CO2 and H2O. The process has the characteristics of small installed capacity, low investment and flexible and convenient start-up.
This process is the key link to reduce the production cost. (6) Landfill technology The original landfill facilities are used in the landfill part of the system.
Scientific and technological innovation has overcome difficulties, and technological integration has solved a series of unique key scientific and technological problems. Mathematical simulation of pyrolysis and incineration and amplification effect of pyrolysis and incineration gasification equipment: Research on gasification and power generation technology and equipment development of organic wastes: Formation mechanism and control method of pollutants during heat treatment: Research on integration, optimization and control of technologies such as sorting, composting, pyrolysis and incineration heating, gasification and power generation, and water gas residue purification.
Through the original unit processing technology. Pyrolysis incineration is a waste incineration technology. On the basis of previous studies, our hospital has developed a strong cyclone pyrolysis incineration technology.
4. How should rural domestic waste be classified?
According to the actual situation of rural domestic waste, domestic waste is divided into four categories according to the treatment and disposal methods or the possibility of resource recycling.
(1) Compostable (organic matter): the main component is domestic organic garbage such as kitchen waste, and the treatment direction is livestock and poultry digestion, direct return to the field, composting, fuel production and biogas production. (2) Inert (inorganic matter): refers to coal cinder, construction waste, etc. Treatment methods include road construction, embankment construction, building filling and landfill.
(3) Recyclable wastes: including waste plastics, paper, glass, metals, waste furniture and electrical appliances, fabrics, leather and rubber. The treatment method is to recycle them by economic means. (4) Hazardous wastes: such as pesticide bottles, expired drugs, batteries, lamps, paint buckets, etc. Strengthen management and concentrate on safe disposal.
5. How to classify rural garbage?
In the garbage sorting yard, more than a dozen sorting workers weigh and load the sorted and packaged garbage. The large forklift in the garbage factory shovels the waste garbage that needs to be buried into the cleaning car, and the whole garbage sorting process is carried out in an orderly manner.
Garbage classification will be an important part of garbage disposal in the future. At present, Guangzhou is implementing garbage sorting in the whole city, but the effect is not obvious. It is difficult to classify urban garbage, especially in rural areas. In this case, Zhong Luotan Town, Baiyun District, Guangzhou adopted a compromise approach: set up a garbage transfer point, that is, through the transfer point, the garbage in the whole town will be concentrated in the sorting yard, and then classified. Garbage classification map
Zhong Luotan takes the lead in setting up a garbage sorting yard in Baiyun District, and cooperates with the ongoing village sweeping and town transportation project to sort the garbage to maximize the rational utilization of garbage resources. This method can not only recycle valuable waste resources, reduce landfill, protect the environment, and make resources get reasonable returns, but also establish a more scientific long-term mechanism for garbage disposal, saving resources for cleaning and environmental protection.
In addition, Zhong Luotan Town also operates the garbage sorting yard in a market-oriented mode of bidding, and contracts the garbage sorting yard to a professional cleaning company in the form of bidding. Market-oriented operation cannot solve all problems. At present, Zhong Luotan Town is mainly responsible for the supervision and coordination of enterprises, and collecting cleaning fees after getting rid of heavy garbage transfer.
The town's garbage compression station is located in fertile fields and bamboo fields, far from the garbage sorting yard. Because there is no garbage compressor in the sorting yard, the garbage that needs to be landfilled needs to be reloaded and transported to two garbage compression stations for reprocessing. The way of garbage disposal in Zhong Luotan provides a reference for rural garbage disposal.
6. What is rural garbage?
Rural waste refers to objects including domestic waste, livestock and poultry breeding waste, crop straw, forest product waste and other wastes.
Among them, domestic garbage includes furnace ash, muck, commodity packaging, human and animal feces (excluding large-scale industrialized farming feces), waste batteries, kitchen garbage, gardening garbage, abandoned daily necessities and other wastes. Livestock and poultry breeding waste refers to solid waste such as feces, sewage generated by farms, padding of livestock and poultry houses, waste feed, scattered feathers, and malodorous gases such as hydrogen sulfide and ammonia.
Crop straw is the general name of the residue of crops after processing and extracting seeds. As far as Zhejiang Province is concerned, there are many kinds of crops, including rice, wheat, corn, beans, potatoes, melons, oilseeds, cotton, sugar cane and so on.
Straw and rice husk after rice is taken out are called straw. The waste of rural forest products mainly includes abandoned wooden furniture, wooden buildings (such as wooden doors and windows), wood shavings, sawdust and disposable chopsticks. In addition, waste writing paper and paper beverage boxes also belong to the waste of forest products.
7. Common sense of garbage classification
Judging from the classification methods of municipal solid waste at home and abroad, it is generally classified according to the composition and output of garbage, combined with the resource utilization and treatment methods of local garbage. For example, Germany is generally divided into paper, glass, metal, plastic, etc. Australia is generally divided into compostable garbage, recyclable garbage and non-recyclable garbage; Japan is generally divided into combustible garbage, nonflammable garbage, and so on. At present, domestic garbage in China can be roughly 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 for power generation, composting and resource reuse.
Recyclable waste
It mainly includes waste paper, plastic, glass, metal, cloth and so on.
kitchen waste
Include food waste such as leftovers, bones, roots, leaves and peels.
hazardous waste
Including waste batteries, waste fluorescent tubes, waste water silver thermometers, expired drugs, etc. These wastes need special safety treatment.
other waste
Including bricks and tiles, waste residue, toilet waste paper, paper towels and other wastes that are difficult to recycle, sanitary landfill can effectively reduce the pollution of groundwater, surface water, soil and air.
8. What problems should be paid attention to in the successful implementation of classified collection and treatment of domestic waste in rural areas?
Rural residents in China generally have a low level of education and the distribution density of villages is low, especially in natural villages in mountainous areas and coastal areas. To establish the collection, transportation, treatment and disposal system of rural domestic waste in China, we should pay attention to the selection of collection and transportation equipment, the planning of transportation routes and the investment of system operation funds.
In addition, in order to ensure the normal and continuous operation of the system, it is necessary to continuously increase environmental protection propaganda and improve villagers' environmental awareness. Generally speaking, to successfully implement the classified collection and treatment of rural domestic waste, we should pay attention to the following issues.
(1) In view of the present situation of disorderly discharge of rural garbage, a system of source sorting and classified collection and transportation should be established according to the characteristics of rural population distribution density, from the aspects of collection and transportation cost, resource recovery and classification treatment. On this basis, the garbage on both sides of rural roads, on both sides of rivers and around farmers' houses will be cleaned up and transported to counties (cities) for treatment through township transfer stations.
In addition, we should also increase the development and popularization of economical and effective technologies for recycling rural domestic waste, such as recycling biogas by garbage fermentation and producing organic and inorganic compound fertilizer by composting. (2) To find a suitable source of funds to ensure the continuous and stable operation of garbage sorting.
The cost of the continuous and stable operation of the garbage collection and transportation system is difficult to maintain only by the financial support of towns and villages. Due to insufficient financial input, garbage collection and transportation equipment and cleaning personnel in some places are uneven.
Therefore, the financial department should arrange special funds for rural garbage collection, transportation and treatment every year for the construction of sanitation facilities and the operation of sanitation systems. (3) Strengthen management to ensure that management is in place.
On the issue of classified collection, treatment and disposal of rural domestic garbage, we should give full play to the leading role of * * *, invest in the purchase of garbage collection devices, special vehicles for removal, and build garbage transfer stations, which are managed by the town government and actively participated by villagers. (4) Improve villagers' environmental awareness.
Villagers are the first executors of classified collection of domestic garbage. It is very important to improve villagers' awareness of environmental protection and strengthen their understanding of garbage classification for the successful implementation of classified collection of domestic garbage. At the same time, we should also pay attention to determining the classification name according to local living customs, villagers' habits and economic development level. Too much manual subdivision will increase the difficulty of work and reduce the feasibility.
In daily life, everything that can be reused should be reused, and things that can't be reused but can be sold as waste (such as glass bottles, cans, bottles, old rain boots, sandals, etc.). ) should be collected. But in general, due to the poor sales channels, the enthusiasm of rural residents for the classified collection of domestic waste has weakened.