Building Waste Brick Making Machine Production Line Needs "Speed-up" for Building Waste Resource Utilization
Cyclic development is an important strategy for China's economic and social development and an important way to build ecological civilization and promote green development. The 13th Five-Year Plan period is the strategic decisive period for building a well-off society in an all-round way. It is more urgent to improve the quality and efficiency of development and promote the green cycle of low-carbon development. At present, referring to recycling development, the most widely used traditional projects are general industrial solid waste comprehensive utilization, crop straw comprehensive utilization, urban kitchen waste resource utilization and so on. However, the resource utilization of construction waste is still not paid enough attention, the development of related industries is still in the exploratory stage, and few enterprises have good profits.
The increment of construction waste is huge, and the treatment method is relatively backward.
The increase of construction waste in China mainly comes from the demolition of existing buildings and the construction of new buildings. Since 2012, although the area of building demolition in China has been decreasing year by year, from 650 million square meters to 460 million square meters in 2017, the production of building waste per unit area has increased due to the structural transformation of demolished buildings to reinforced concrete structures. Therefore, the annual production of building waste is still about 500 million tons. In terms of housing construction, the construction area of the whole country has increased rapidly since 2006, and the growth rate has slowed down in the past two years, but it remains at a high level. In 2018, the construction area of the whole country is 14.08 billion square metres, which produces 0.055 tons of construction waste per square metre, generating about 700 million tons of construction waste. According to this calculation, China adds more than 1.2 billion tons of construction waste every year.
Corresponding to the increase of construction waste, the disposal methods of construction waste in China are still in a relatively extensive stage of landfill and storage. At present, domestic standards for recycled products of construction waste resources have not formed a system. Landfill, Hill piling and on-site mobile equipment disposal are the main disposal methods of construction waste resources, and environmental pollution is serious in the process of disposal. According to 10,000 tons of construction waste covers an area of 2 mu (heap height of 5 meters), about 1.2 billion construction waste is produced annually in China, and the occupation of land resources will exceed 240,000 Mu a year.
Landfill treatment of construction waste has serious drawbacks. First, dust and ash are flying everywhere in the process of cleaning, transportation and storage, which pollutes the environment. Second, landfill occupies national land and wastes land resources. Thirdly, paint and coatings in construction waste contain harmful substances, which are not easy to be decomposed after landfill, thus polluting groundwater. Fourthly, landfill will also destroy soil structure and cause surface subsidence.
In some areas, fixed facilities are disposed of, and the rate of resource utilization is generally below 80%. Unresourced parts will cause serious secondary pollution. The profit model is mainly supported by government subsidies and policies. Without subsidies, it can not operate normally and does not form a business model recognized by the market. China's construction waste industry is in urgent need of resource-based disposal and high value-added utilization. However, the current national standards for recycled products are small in number, low in standard and old in standard age. Clear standards are needed to regulate all aspects of construction waste recycling.
Low disposal rate of construction waste and slow improvement of disposal capacity
In recent years, although a series of laws and regulations related to construction waste management have been issued, due to the limited capacity of government-designated construction waste disposal sites, the construction unit's construction waste can not be effectively disposed of through formal channels, and most of the construction waste is treated privately by illegal ways by construction units.
Only 10% of the construction waste in most cities is transported to designated disposal sites. The main reasons for these extensive disposal methods are as follows: firstly, there is no classified collection of construction waste; secondly, there is a lack of professional construction waste recycling institutions; thirdly, the technology level of construction waste disposal and resource utilization in China is relatively backward; fourthly, the government has little support for the resource utilization of construction waste.
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