Qingdao, a green city, is the first in China! Out of ＂Qingdao Model＂ of Construction Waste Recycling in ＂Zero Carbon Factory＂
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As the first pilot city for the construction and development of green cities in China and the only pilot city in the north where government procurement supports green building materials to improve building quality, in recent years, Qingdao has actively implemented the national "double carbon" strategy, accelerated the implementation of green projects, and achieved a series of positive results. From now on, this newspaper will open the column "Green City Qingdao First", focusing on the city’s green and low-carbon development, approaching pioneers, outstanding enterprises, industrial parks and low-carbon communities, telling the story and successful experience of Qingdao’s green development, showing Qingdao’s fruitful achievements in the fields of green energy saving, green construction, green life and green transformation and development in recent years, and writing a "green answer sheet" for Qingdao to achieve the goal of "peak carbon dioxide emissions, carbon neutrality".
Peninsula all-media reporter Guo Zhenliang
In recent years, Qingdao has continuously innovated the production technology of recycled building materials, promoted the development of green cities, pushed the 5 million tons of construction waste resource utilization project "Zero Carbon Factory" into operation smoothly, and took the lead in forming a "50" production cycle system with zero waste, zero waste water, zero exhaust gas, zero waste heat and zero energy consumption in the country, realizing 100% full utilization of construction waste. In 2021, the annual utilization of construction waste in Qingdao reached 37 million tons, and the utilization rate exceeded 70%, which kept the national leading level, and created a replicable, scalable and sustainable "zero-carbon path" for creating a beautiful Qingdao with "ecological priority, green and low carbon".
Qingdao "Zero Carbon Factory" realizes 100% full utilization of construction waste.
With the increasing expansion of urban scale, Qingdao produces about 50 million tons of construction waste every year in the process of urban construction such as the transformation of old cities and old villages and infrastructure. For example, if the earthwork excavated by Jiaozhou Bay subsea tunnel is taken as the unit of measurement, the total amount of construction waste in Qingdao is about 50 million tons per year, which is equivalent to 20 subsea tunnels, which is a huge amount. Where did such a huge amount of construction waste go? What are the uses? Recently, the reporter walked into Qingdao Lufan 5 million tons construction waste resource utilization industrial park on the coast of Jiaozhou Bay with questions. Here, more than 10,000 tons of construction waste from various districts and cities in Qingdao are processed into recycled aggregate and various recycled building materials products after a series of processes such as sorting, crushing, screening and washing on the production line every day, and are used in various urban construction projects, and the waste materials glow with new life.
Chen Yong, chairman and general manager of Qingdao Lufan Recycling Building Materials Co., Ltd. told the reporter: "Construction waste mainly includes engineering dregs, waste concrete, metal, glass, wood, paper and other components. If it is not properly disposed, it will lead to a series of ecological problems such as soil pollution and water pollution. With the strong support of Qingdao government departments, we take the initiative to assume social responsibilities, revitalize construction waste, and build an integrated project of construction waste disposal, production and recycling, with 5 million tons of construction waste resources.
According to reports, the project has a total investment of 292.407 million yuan, covering an area of 158 mu. After it is completed and put into operation, it can handle 5 million tons of urban construction waste, produce 1.2 million cubic meters of recycled aggregate concrete, 600,000 cubic meters of stabilized soil for highway base, 80 million pieces of recycled aggregate fly ash bricks, 80 million pieces of permeable pavement bricks, 400,000 cubic meters of aerated concrete blocks, 150,000 cubic meters of sand aerated concrete slabs, and so on. After the project is fully completed and put into production, it can save 4.7 million tons of natural aggregate sand and gravel every year, greatly alleviating the current situation of over-collection of sand and gravel, saving 600 mu of landfill land, reducing the pollution of surrounding 1,600 mu of land and underground water sources, and reducing the emission of carbon dioxide by 1.5 million tons, with remarkable environmental benefits.
Last year, the first phase of the industrial park project was just completed and put into operation. Qingdao Lufan performed social welfare with excellent technical strength and properly disposed of a garbage mountain piled up by the sea for a long time. "At that time, mosquitoes and flies were everywhere, and the smell was stinking. It was estimated that there were nearly 600,000 tons of mixed garbage to be disposed of. If it was 10 tons per car, 60,000 trains would be needed for transportation. The huge workload became the first problem faced at the beginning of the completion of the industrial park, but in the end, after more than three months of working overtime day and night, we successfully ate this garbage mountain by the sea, turned comprehensive garbage into environmentally friendly building materials, and made Qingdao’s seaside environment return to green ecology. " Chen Yong said.
The reporter saw in the industrial park that although the machines in the production line building roared, the outside of the building was not affected by noise, and the whole park was not only neat but also quiet. In this regard, Chen Yong said that the construction of the park adopts a gentle slope design, which reduces the dust and noise pollution during processing, increases the public space and improves the air quality. In addition, a spacious green belt is designed around the building, and fresh water produced by rainwater collection system and waste steam desalination system is used for irrigation. Office and domestic electricity is not only supported by photovoltaic power generation, but also assisted by waste steam power generation.
The country took the lead in forming a "50" production cycle system.
Qingdao "Zero Carbon Factory" not only used recycled and environmentally friendly building materials in the construction process, but also formed a national leading "50" production cycle system with zero garbage, zero waste water, zero waste gas, zero waste heat and zero energy consumption in the production management stage after completion.
Chen Yong said: "One principle of our production and R&D is that the waste of the last product is the raw material of the next product. With the concept of recycling as the core, we turn construction waste into treasure through refined disposal and precise utilization. All the production processes adopted are independent research and development, and we have 16 patents at present. Typical technologies include light material rinsing and brick-concrete separation technology, and the separation rate reaches 100%, which ensures the quality of building materials products from raw materials. Large pieces of plastic produced in the separation process can be sold directly after cleaning, and wood, paper, cloth, etc. are directly used as fuels for biomass boilers in the field, thus achieving a high degree of matching between output and raw materials in different processes, and no waste is generated in the whole process. "
In order to meet the large water demand in the production process, Qingdao Lufan has realized the intensive utilization of water resources from two ways: open source and throttling. Firstly, the waste water generated in the production process is recycled after being treated in the field, and at the same time, the sediment in the waste water for cleaning aggregates is recovered to be used for producing quick-drying, high-strength and waterproof water-stabilized macadam, or mixed with red brick aggregate to produce fly ash autoclaved brick; After domestic sewage is treated, reclaimed water is used for production, and organic waste is used for producing organic fertilizer or planting soil. The second is to design a rainwater collection channel in the park, and the collected rainwater will be used for production after treatment. In the second phase of the project, it is also planned to use stone-like permeable pavement slabs to solve the problems caused by the large seasonal temperature difference of permeable concrete in the northern region by using structural permeable technology.
Chen Yong said: "A lot of steam will be generated in the production process. In order to avoid the environmental problems caused by direct discharge, the project will use the discharged primary steam for magnetic levitation power generation, the secondary steam for PC oxygen steaming room and seawater desalination system, and the generated high-temperature desalinated seawater will provide hot water for heating nearby residential quarters, and the tertiary steam will become high-pressure steam after passing through the steam generator, which will be used to produce board and fly ash autoclaved bricks. In addition to waste gas, a large amount of waste heat is generated in the production process. For this reason, a flue gas waste heat recovery system is designed, which is combined with seawater desalination system, and a seawater circulation system is added in the chimney to cool the flue gas to 40 degrees, and at the same time, it also wastes seawater, realizing colorless, heat-free and tasteless flue gas discharge, contributing to reducing the urban heat island effect. "
Finally, the energy system accounts for the largest proportion of carbon emissions and costs in the whole production process. In Qingdao Green Sail Construction Waste Zero-carbon Park, a zero-carbon energy solution integrating energy use, production capacity and function is formed through the integrated application of technologies such as photovoltaic, biomass boiler and energy cascade utilization, combined with the energy demand inside and outside the industrial park. The integrated photovoltaic design is adopted for the production power of the project. A solar photovoltaic power generation system is laid on the roof and south facade of the factory building, with an installed capacity of 6 MW, and the total power generation can meet the demand for production and lighting. At the same time, all concrete mixers in the field use electric vehicles, which are charged by photovoltaic green electricity in the factory area, and used as mobile electricity storage equipment of photovoltaic system to enhance the flexible electricity consumption in the park. In the second phase of construction, the whole building facade decoration and lighting are integrated with photovoltaic design to realize the construction of zero-carbon energy system in the whole park.
Create a beautiful Qingdao and walk out of the "zero carbon path"
In 2021, Qingdao’s annual utilization of construction waste reached 37 million tons, with a utilization rate of over 70%, and maintained a leading position in the country. From January to April this year, the city’s enterprises used a total of 10.636 million tons of construction waste, saving about 1,064 mu of land and reducing the pollution of surrounding land and water sources by about 3,192 mu, with an output value of about 1.097 billion yuan.
Li Yi, director of Qingdao Building Energy Conservation and Industrialization Development Center, said that we will take many measures and do a good job in resource utilization. Strengthen source management, conduct on-site investigation before construction projects start, and implement the primary responsibility of construction waste discharge units. Improve the way of disposal and utilization, constantly innovate the management mode of resource utilization of construction waste, research and develop new technologies for resource utilization, and improve the resource utilization rate. Strengthen coordination with the municipal urban management bureau and other departments, make full use of intelligent supervision, daily inspections and other means, strengthen the supervision of construction waste discharge, and promptly investigate and deal with illegal disposal and utilization of construction waste. Conscientiously sum up and popularize advanced experience, based on the development concept of "carbon neutrality in peak carbon dioxide emissions", comprehensively sum up the experience of "50" production cycle system in Green Sail Zero Carbon Industrial Park, and popularize it in the whole city.
According to the "14th Five-Year Plan" for building energy conservation and green building development, Qingdao will strengthen the resource utilization of construction waste, continue to strengthen the role of the Regulations on Resource Utilization of Construction Waste in Qingdao, further improve the mechanism and system for resource utilization of construction waste, and focus on policy system construction, industrial park planning, and research and development of new technologies and equipment. During the planning period, the resource utilization rate of construction waste will reach 75%, and the "Qingdao model" for promoting the resource utilization of construction waste will be improved.
