So, what problems does the illegal dumping of construction waste reflect? Is there a feasible path for resource utilization? With these questions, the reporter interviewed relevant people.
Efficient utilization of construction waste resources is the direction
Construction waste mainly includes five categories: engineering muck, engineering mud, engineering waste, demolition waste, and decoration waste.
According to the calculations of the housing and construction department, our country's annual production of urban construction waste exceeds 2 billion tons, which is about 8 times the amount of domestic waste and accounts for about 40% of the total urban solid waste.
"The simple and disorderly landfilling of construction waste not only increases the burden of ecological and environmental pollution, but also brings a series of social additional costs and negative impacts, and ignores its own potential resource value attributes, which is contrary to the new management concept of 'waste-free city' and green construction." Hao Linbo, chief engineer of the third business department of China Construction Technology Group Zhongcheng Institute (Beijing) Environmental Technology Co., Ltd., said.
In Hao Linbo's view, although the construction waste itself is complex and difficult to fully realize the front-end classification, but through the steady development of the past 20 years, our country's construction waste treatment industry has gradually moved towards the stage of automated production, and "efficient resource utilization" will become the theme of construction waste treatment.
For the construction waste that can be used for resource utilization, Liu Jianguo, professor of the School of Environment of Tsinghua University and director of the Institute of Solid Waste Control and Resource Utilization, gave a specific explanation: engineering muck is mainly sand, gravel, fill, etc., which can be used for engineering backfilling, greening landscaping, terrain piling, etc. as much as possible, and can also be used to produce recycled sand and gravel; The engineering mud is a slurry-water mixture, which is used locally by means of on-site cleaning, sediment separation, etc. as much as possible, or further processing and utilization of sediment after dehydration and drying. Engineering waste mainly includes concrete, bricks, blocks, metal and other waste materials, which can be directly reused for the project after processing on site, and cannot be used on site. Demolition garbage mainly includes waste steel bars, concrete, bricks, blocks, wood, plastics, etc., and higher value steel bars, aluminum-plastic doors and windows can be separated on site and enter the renewable resource recycling channel, and the remaining part is produced with engineering waste to produce recycled products. The source of decoration waste generation is more dispersed, the components are more volatile, there are more debris, and the quality is lower, and it should enter professional facilities to produce recycled building materials, derivative fuels, etc.
"From the perspective of form, the resource utilization methods of construction waste include material recovery, material conversion (transporting the recycled construction waste to the resource treatment plant, and converting it into recycled products or materials that can be used to make new products through technical means) and energy transfer (converting the energy contained in construction waste into recyclable energy after treatment)." Hao Linbo added.
These pilot explorations can be used as a reference
In order to strengthen the management of construction waste, the Ministry of Housing and Urban-Rural Development organized 35 cities (districts) including Beijing to carry out pilot exploration work on construction waste management in 2018, forming a number of good experiences and practices, which have been replicated and promoted in various places.
For example, Beijing has clarified the applicable standards for 12 types of recycled building materials from construction waste, included the use of recycled products in the application and review of government investment projects, and required that the proportion of recycled products used in government investment projects should not be less than 10%.
In November 2022, Beijing issued the "Opinions on Further Strengthening the Classification and Disposal of Construction Waste and the Comprehensive Utilization of Resources", proposing to promote the construction of construction waste resource disposal facilities in combination with Yonglin (referring to the overall consideration of the construction of permanent facilities and temporary facilities). The construction waste resource disposal facilities should be finely adjusted into on-site disposal facilities, temporary disposal facilities, and fixed disposal facilities, and the installation and operation of various facilities should meet the relevant standards of the state and the city. Qualified construction units are encouraged to build construction waste screening and crushing production lines within the red line of the project, implement local disposal of construction waste, and dismantle the disposal facilities and restore them to their original state before completion.
"Since 2018, nearly 100 million tons of recycled products have been widely used in key projects such as Winter Olympic venues, Winter Olympic Park, Universal Studios Beijing, urban sub-center, Daxing International Airport Expressway, landscaping, river management, and temporary construction of houses." Liu Jianguo said.
"The ecological restoration project of the Jingxi Basin of the Yongding River has used more than 60,000 tons of recycled water purification filter material, which is put into use as an important carrier for water purification in the wetland system, and can purify and treat 60,000 cubic meters of reclaimed water every day." Li Shuo, deputy general manager of Beijing Construction Engineering Resource Recycling Co., Ltd., introduced.
In addition, according to Hao Linbo, Shenzhen's first construction waste treatment project - Dagangwei reclamation fill pre-site processing and disposal area project - construction waste treatment project, including two pretreatment lines of construction waste and muck, two recycled product lines of recycled pressed bricks and recycled concrete batching plants, with a total investment of about 450 million yuan. Among them, the design treatment scale of demolition and construction waste is 500,000 tons/year, the scale of muck treatment of long-term construction projects is 2 million tons/year, and the single-line production capacity of recycled pressed bricks has reached the first place in Asia.
In the interview, Liu Jianguo also mentioned that Shenzhen has comprehensively promoted the separation of engineering muck and sediment, built the largest sediment separation production line in China, with a design processing capacity of 6 million cubic meters per year, effectively alleviating the difficulties of engineering muck disposal.
Promote the resource utilization of construction waste
"In 2020, the utilization rate of construction waste resources in our country will be about 9%, which has further increased in the past two years." Liu Jianguo made a further analysis of this figure. He pointed out that on the one hand, because our country and developed countries have different construction waste scopes and statistical calibers, and the calculation formula is also different, if according to the calculation method of developed countries, our country's construction waste resource utilization rate is about 40%. On the other hand, because our country's construction waste components are more complex, resource utilization is difficult, facility capacity is insufficient, supporting and support policies are not perfect, product prices do not have market advantages, and market promotion and social acceptance need to be further improved, resulting in our country's construction waste resource utilization rate is significantly low.
In order to better promote the resource utilization of construction waste, Liu Jianguo suggested that at the level of institutional norms, the competent departments and local governments should strengthen the refined control of the source of construction waste, establish a unified and standardized construction waste classification and statistical system, grasp the generation and flow direction of various categories of construction waste, and promote classified collection, classified transportation, classified treatment and classified utilization.
In addition, in order to improve the capacity of facility construction, construction waste utilization and disposal facilities should be regarded as an important part of urban infrastructure construction, and the layout and scale of construction waste transfer and distribution, consumption and disposal, and resource utilization facilities should be reasonably determined. At the same time, establish and improve the product quality standards and application system of recycled building materials from construction waste, continuously improve the technical and management level of the industrial technology and management of construction waste resource utilization and the quality of recycled building materials products, and gradually eliminate market barriers.
Liu Jianguo also suggested that the safeguard measures for the utilization and disposal of construction waste should be implemented in terms of planning land security, cost mechanism, fiscal and tax preferential policies, green procurement, etc., combined with the "double carbon" goal to improve the market competitiveness of construction waste recycling products, and cultivate a number of backbone enterprises for the resource utilization of construction waste.
Hao Linbo pointed out that in order to promote the high-quality development of the industry, it should be based on mechanism research and based on key technological innovation to improve the added value of resource products; On the basis of in-depth diagnosis of "urban diseases" and "foci", identify breakthroughs in development and make overall planning.
