The content of this article comes from the Capital Science Lecture Hall hosted by Beijing Science and Technology Association , hosted by Beijing Science Center, and co-organized by Beijing Science and Technology News Agency. The lecture hall invites academicians and experts to give lectures every week to spread scientific knowledge and scientific methods, promote the scientific spirit and scientific culture, and promote the public to fully and correctly understand science.
Recently, The Ministry of Ecology and Environment issued the "Notice on Release of the List of Construction of "Waste-free Cities" in the "14th Five-Year Plan" Period". The notice clearly states that during the "14th Five-Year Plan" period, the Ministry of Ecology and Environment will promote the construction of " waste-free city " in about 100 cities at the prefecture level and above, and encourage provinces with conditions to promote the construction of "waste-free city" throughout the region. What is a "waste city"? What are the standards for the construction of "waste-free cities"? How can ordinary citizens participate in the construction of "waste-free cities"?
This issue of the Capital Science Lecture Hall invites Tsinghua University School of Environment Long-joined professor Li Jinhui to explain to us how "waste-free cities" can turn waste into resources.
guest speaker:
Li Jinhui
Tsinghua University School of Environment, United Nations Environment Programme Union Environmental Programme Executive Director of the Asia-Pacific Regional Center of the Basel Convention, and Executive Director of the Asia-Pacific Regional Center of the Stockholm Convention
▲How far is the "waste city" from us? (Part 1)
▲How far is the "waste-free city" from us? (Part 2)
Solid waste problem plagues urban development
We are building livable city , its standards include high social civilization, high economic affluence, high environmental beauty, high resource bearing, high living cheapness, and high public safety.
▲Living City (Photo provided by Li Jinhui)
But livable cities face a very big challenge - the problem of solid waste. Humans will produce various kinds of waste in the process of production and life, some of which are solid waste, and the others are wastewater, waste gas, etc. Our country is a country with a large population and must be a country with a large solid waste production. Currently, the cumulative storage of various solid wastes in my country is about 80 billion tons, with an annual production volume of nearly 12 billion tons, and is showing an annual growth trend. If not properly handled and utilized, it will cause great waste of resources, seriously pollute the environment, and have a bad impact on society.
▲The current cumulative storage of various solid wastes in my country is about 80 billion tons, with an annual production volume of nearly 12 billion tons, and is showing an annual growth trend (Photo provided by Li Jinhui)
In fact, solid waste is first of all the resource attributes - urban minerals. We can regard solid waste as urban minerals, and garbage is a resource that is placed in the wrong place. For example, recycling non-ferrous metal in some waste slag, recycling waste glass into new glass products , etc. In addition, we can transform the performance of solid waste. For example, waste glass and waste rubber are used to produce paving materials. Another type is to convert solid waste energy, such as using solid waste to produce electricity.
solid waste has one most important attribute, which is the risk of the ecological environment. The harmful components of solid waste that have been stacked in the open-air for a long time migrate to the surrounding and deep soil through soil pores through soil adsorption and other effects of soil, which in turn pollutes the plants growing in the soil. The severely polluted land cannot even be cultivated, and loses its use value.
solid waste will also cause air pollution. If the corresponding protection and purification measures are lacked during transportation and processing, fine powder and dust will scatter with the wind; waste piled and landfilled and waste seeped into the soil will release harmful gases through volatile and chemical reactions, which will seriously pollute the atmosphere and reduce the quality of the atmosphere.
solid waste can also contaminate water bodies.Solid waste is carried into the water by rainwater by surface runoff, or tiny particles floating into the air fall into the surface water body through rainfall and gravity settlement. The water body may dissolve harmful components, pollute water quality and poisonous organisms. Some simple landfills, leachate produced by filtration of rainwater or biochemical degradation of waste, contain high concentration of suspended solid substances and various organic and inorganic components. If this leachate enters groundwater or shallow aquifers, it will lead to severe water pollution and will be difficult to manage.
We live in the environment, using the atmosphere, water and soil as the medium, and can directly ingest harmful waste in the environment into the human body from the respiratory tract, digestive tract or skin, causing disease. Therefore, we must "clean and scientifically process urban domestic waste".
solid waste will also affect the city appearance. The open-air piles and simple landfill of domestic waste will not only occupy a large amount of land resources, but also the domestic waste piles in the suburbs are prone to breed mosquitoes, flies, maggots and stench, affecting the cityscape and hindering the landscape. As garbage is thrown away, plastic bottles floating on the water surface and plastic bags hanging on the trees seriously affect the view of the natural landscape.
solid waste also has safety risks. During the corrosion process of domestic waste, it will produce biogas and harmful substances, including methane , carbon dioxide , carbon monoxide , ammonia, hydrogen sulfide , etc., which will produce foul odor, which is prone to spontaneous combustion and self-destruction, and poses safety hazards.
The problem of solid waste also has social attributes. Every member of society produces and discharges solid waste. The generation of solid waste means the consumption of social resources and has an impact on society. The emissions, treatment and disposal of solid waste and their pollution affect the interests of others.
▲The social attributes of solid waste determine that reducing solid waste is everyone’s responsibility (Photo provided by Li Jinhui)
The social attributes of solid waste involve the “neighbor avoidance movement”. "Nearby and Avoid Sports" means "don't build garbage disposal facilities near my home." In the 1970s, someone discovered that dioxins appeared in the fly ash in three garbage incinerators in Finland . Dioxin is a carcinogen, so the public is worried that the incineration of garbage may produce carcinogenic substances and harm the public's health. Therefore, it resists the construction of waste incineration treatment facilities.
With the continuous improvement of social and economic development and consumption levels, the changes in public living habits and urban environment, the production of urban domestic waste has increased rapidly, and environmental risks are becoming more and more prominent. Many cities in the world have experienced "garbage siege" situations, which has seriously restricted urban development.
So where do we go to the garbage?
actually has the following way out. The first way out is to enter the incineration plant of domestic waste. In China, the proportion of waste incineration has reached more than 60%. At present, China's technology and management level are in a relatively advanced position in the world. There are also some domestic waste incineration plants in Beijing, and everyone can make an appointment to visit.
▲The proportion of garbage incineration in China has reached more than 60% (Photo provided by Li Jinhui)
Waste incineration is the process of reducing the capacity through appropriate thermal decomposition, combustion, melting and other reactions, and reducing the capacity of the garbage after oxidation at high temperature, becoming a residue or melting solid substances.
Waste incineration facilities must be equipped with flue gas treatment facilities to prevent heavy metals, organic pollutants, etc. from being discharged into the environmental media again. Recycling of heat generated by waste incineration can achieve the purpose of waste resource utilization. The advantage of waste incineration is that the incineration technology can reduce capacity by more than 85% and reduce capacity by more than 75%, highlighting the reduction and harmlessness. The heat generated by the incineration process can be used to generate electricity to achieve energy-based waste. The disadvantage is that improper control of incineration conditions will cause flue gas pollution problems and huge investment in equipment.
The second basic method of garbage disposal is landfill.Its advantage is that it is simple to operate and can handle all kinds of garbage. However, its disadvantage is that it covers a large area and has serious secondary pollution. For example, garbage ooze will pollute groundwater and soil, and the odor generated by garbage dumping seriously affects the air quality around the site. The methane gas produced by garbage fermentation is both a hidden danger of fire and explosion, and will also produce greenhouse gas when it is discharged into the atmosphere. The most important thing is that the landfill has limited processing capacity, and after the service period expires, it is still necessary to invest in the construction of a new landfill to further occupy land resources.
▲Landfill is the most basic method of disposing of urban garbage (photo provided by Li Jinhui)
garbage disposal method and compost. Our family’s kitchen waste is actually organic and can be made into fertilizer. We use special equipment to crush organic garbage and ferment in a concentrated manner, and add specially cultured microorganisms to degrade the organic matter in it and form compost. Its advantage is that the process is relatively simple and suitable for the disposal of perishable substances, and the investment is greatly reduced compared to simple incineration treatment. The disadvantage is that it cannot handle non-rotten organic and inorganic substances, so the degree of capacity reduction, volume reduction and harmlessness is low. Relying on compost treatment alone still cannot completely solve the garbage problem. Fresh garbage must be sorted first, and then perishable organic components are fermented to effectively prevent heavy metals and other substances from infiltration, thereby ensuring that organic fertilizer products meet national standards and truly achieve harmlessness and resource utilization.
▲Schematic diagram of garbage composting (photo provided by Li Jinhui)
What is the concept of "no waste"?
So what is the concept of "no waste"? The International Alliance for No Waste (NGO) first gave "no Waste" (zero) in 2004 Waste)’s working definition, and in 2009, organized experts to revise the definition: “Waste-free is an ethical, economical, efficient and visionary goal to guide people to change their daily lifestyles and practices to emulate the sustainable cycle of nature. All waste materials are designed as resources available for use by other processes. ‘Waste-free’ requires systematic design and management of products and processes, avoiding and reducing the amount of raw material use and waste production, reducing toxic substances in raw materials and waste, protecting or recycling all resources, rather than treating waste in incineration or landfill.”
“waste-free” concept adheres to a principle of domestic waste management, first of all, reducing quantification. Of course, in China, our understanding is actually deeper. Not only is the reduction of the process, we also regard the improvement of social governance and the adjustment of industrial results as an integral part of the reduction. The second is resource utilization. We collect more recycled resources so that they do not enter the incineration plant of domestic waste. The third is energy utilization, such as incineration and power generation. The fourth is harmless landfill. During the landfill process, we use appropriate engineering methods to prevent environmental pollution.
The entire system becomes a loop, which is what we call a loop chain. All matter is circulated in this circle, and we can obtain more resources to support it without the help of external forces.
The concept of "waste-free city" is determined in relevant national documents, but "waste-free city" does not produce waste, but reduces the amount from the source through the transformation of green production methods and lifestyles, and uses it in order to minimize the amount of incineration and landfill.
The concept of "waste-free city" is not just a problem with the waste itself, but actually a reverse pressure mechanism. After all, if cities want to develop, the economy needs to develop, production still needs to be carried out, so it is to promote the sustainable development of the social economy through reverse pressure mechanisms. Therefore, it is another new model of urban development.
"Waste-free city" will bring many benefits. The first is that through this work, we can form a rapid development of the solid waste treatment and disposal industry.If policies are guaranteed and a group of key enterprises will meet the conditions to carry out technological innovation, then the development of this industry will be sustainable.
The second is that the construction of "waste-free cities" can promote the construction of solid waste treatment and disposal facilities.
The third is that the construction of "waste-free cities" can vigorously promote social sustainability. For example, "wasteless" hotels, "wasteless" scenic spots, "wasteless" islands, "wasteless" communities, "wasteless" campuses, etc., including green packaging, these are "wasteless" cells for the construction of "wasteless cities".
The fourth is that the construction of "waste-free cities" can vigorously promote the public to reduce waste and reduce the consumption of energy resources. Through the dissemination of "wasteless city" culture, everyone will have a "wasteless" awareness, do not waste resources, and do not waste energy, and the sustainability of society will be greatly improved.
The construction of "wasteless cities" in the world
973, Dr. Paul Palmer of Yale University proposed for the first time "wasteless". In 1989, California, the United States passed the Integrated Waste Management Act, setting a waste landfill reduction target. In 1996, the Australian capital, Canberra , passed the No Waste by 2010 Act, becoming the first city in the world to officially establish a "no waste" goal. In 2003, San Francisco, the United States and Katsumachi, Japan respectively set high-standard waste-free targets in the same year: to completely replace landfill and incineration by 2020.
▲The development process of the concept of "no waste" (photo provided by Li Jinhui)
Europe formulates a "no waste" plan, Japan promotes a circular society, Singapore put forward a "no waste" national vision, and also drives its partners to build "no waste city". For example, in China, Singapore established a "waste-free city" in Suzhou Industrial Park , and Tianjin Eco-City is actually an achievement of China-Singapore cooperation.
Japan actually promotes social construction based on the utilization of material recycling .
There is a regional 3R forum and C40 cities in the Asia-Pacific region. C40 cities are mainly an international network to deal with climate change, and put forward a declaration to accelerate the "wasteless" process. In fact, the management of solid waste is closely related to climate change. UNHabitat and Environment’s smart cities also have waste reduction actions. The Basel Convention regional center managed by the United Nations Environment Program is also promoting the construction of "waste-free cities".
China's "waste-free city" construction
my country's foundation for solid waste treatment is very weak. Although there are laws, the coordination between laws is insufficient and there are deviations in implementation.
First of all, the basic number of solid waste in my country is unclear. Our statistics on domestic waste are actually a transportation volume, which means that residents put the garbage in the garbage can, and there are the amount collected by the sanitation department. However, the statistical data that was subsequently dumped or processed in a distributed manner were not included in the statistics. In addition, we are not sufficient in the innovation of solid waste treatment technology. The country's investment is relatively small, the technical team is not strong, and the social participation is relatively low.
▲Zhejiang Province took the lead in building a "waste-free city" information platform (photo provided by Li Jinhui)
In September 2019, the Ministry of Ecology and Environment, combined with the opinions of 17 other departments, announced to the public the first batch of pilot projects for the construction of "11+5" "waste-free city" to the public. Beijing Economic and Technological Development Zone is one of the pilot projects, and other cities include Shenzhen, Sanya , Baotou , Tianjin, etc.
"Waste-free city" construction has achieved some results. First, the development of the indicator system for the construction of "waste-free city" has enabled my country to have corresponding evaluation indicators when carrying out the construction of "waste-free city" in the "14th Five-Year Plan", "15th Five-Year Plan" and "16th Five-Year Plan".
Second, it is to explore the establishment of a comprehensive management system and technical system for the construction of "waste-free cities". Some pilot cities have formulated some policies and standards, which can be directly referenced in other places; some technologies developed can be used directly in other places.
Third, it is to form a batch of replicable and popularizable "waste-free city" construction models.
, cultivate a group of backbone enterprises for the resource utilization of solid waste. The most core key node in the construction of "waste-free cities" is to undertake it by enterprises.
Some parts of my country have achieved some results in the construction of "waste-free cities".
Himing'an New District builds a "waste-free city" to create a green Xiong'an. In the new construction area and the upgrading and renovation area, the sanitation facilities are scientifically laid out, the demolition and construction management are comprehensively promoted to the design, construction and operation of green buildings, guide the selection of green building materials, actively and steadily promote prefabricated and recyclable building methods, and promote green and high-standard full-process management of construction.
Sanya City through the construction of all-round "wasteless" cell project , establishing a green tourism brand image, establishing a "wasteless" concept publicity system for the tourist population, using tourists as the main body of dissemination of green life and green consumption models, creating a "wasteless city" publicity window, and expanding the radiation and influence of "wasteless city" construction across the country and the world.
Shenzhen City builds a benchmark city of "waste-free cities". In terms of construction waste, through the reduction of emissions at the source of the construction process, resource utilization of construction waste and multi-channel disposal, intelligent supervision of the entire process.
▲Shenzhen's "waste-free" treatment of construction waste (photo provided by Li Jinhui)
Beijing Economic and Technological Development Zone is the first in the industrial field to write the source reduction of solid waste into the "Beijing Economic and Technological Development Zone Clean Production Management Measures", reducing the production of solid waste from the entire production process of enterprise. The " Internet + source classification" model is formed in Ronghua Street. "One household, one code" establishes a QR code for community residents, "One household, one bucket" realizes the classification and collection of kitchen waste , and "One household, one bag" promotes the classified disposal of recyclables. Using the full-link solution for garbage classification - the platform system of JD Life Classification Space Station, the collection weight, number of collections, points collection and back-end collection and transportation of recyclables are refined.
▲Beijing Economic and Technological Development Zone embarked on the road of "wasteless" (photo provided by Li Jinhui)
Weihai City uses "wasteless city" to create a "exquisite city - happy Weihai ". Through model innovation, the ecological restoration of mine pits and the construction of tourist attractions in the Longshan area will be carried out, and the mine pits will be built into 5A-level scenic spots to drive the development of the regional economy.
On October 24, 2021, the State Council issued the "Action Plan for Carbon Peak Before 2030", which will integrate carbon peak into the entire process and all aspects of economic and social development. In December 2021, the Ministry of Ecology and Environment and 18 other departments jointly issued the " Work Plan for the Construction of "Waste-free City" in the "14th Five-Year Plan" period. On April 24, 2022, the Ministry of Ecology and Environment released a list of "waste-free cities" construction during the "14th Five-Year Plan" period.
country is promoting, so what should we do? In fact, it is a very important challenge for us. We must establish "wasteless" institutions, "wasteless" schools, "wasteless" communities, "wasteless" shopping malls, "wasteless" scenic spots, "wasteless" hotels, "wasteless" factories, "wasteless" parks, etc. For example, in a "wasteless" school, every student can use used books for lower grade students to use, whether paper can be used less, whether it can be recycled, etc.
▲The resource value of garbage can be enhanced through garbage sorting (photo provided by Li Jinhui)
In addition, everyone should actively spread the "waste-free" culture. Millions of students across the country should all transmit the concept of "no waste".
Another thing is to implement the classification of domestic waste. We develop habits in our lives and dispose of garbage according to the standards of garbage classification.
Countries are also constantly increasing investment in solid waste management and research and development, and continuously strengthening solid waste management and policy and institutional innovation. These support makes our "waste-free" vision look forward to.
I hope everyone will strive to be an advocate, practitioner and leader of "no waste".
(The pictures and videos of this article are from the Capital Science Lecture Hall in Issue 766)
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Source: Capital Science Lecture Hall
Editor: Gulu
