China has a construction waste problem. Like anywhere else, China’s structures gradually reach the end of their useful life as they fall into disrepair or age beyond usefulness, whereas others face more dramatic destruction due to natural hazards. Unfortunately, much of this construction waste in China is … wasted. But to what degree, and why? This article explores the elements affecting this abundant resource, and the opportunities available to those that decide to capitalise on its surprising value.
How does China define this waste?
Waste is generated during construction, refurbishment, and demolition by contractors, as well as domestic decoration and renovation. China divides this waste into soil and mud, and waste derived from construction, demolition, decoration and refurbishment.
Soil and mud are generated mainly from construction, trenching and basic engineering works.
The table below summarises the composition and common uses (or lack thereof) of each of the types of waste:
Construction waste resource utilization includes waste generation, storage, transportation, disposal, and the comprehensive use of recycled products. This involves traditional construction, and the production and transportation of building materials. It should be emphasised that utilization of construction waste should start from the design phase and continue through construction. In the former, for example, we should consider the intended lifespan of certain elements, and which will be able to be reused after dismantling. This recycling can be achieved through simple physical processing, or through burning. The products commonly produced include sintered goods, such as bricks, and road engineering materials, like backfill soil and concrete aggregate. Concrete is broken and used as aggregate to produce cement products, including bricks, blocks, and wall panels.
The current status of construction waste in China
In our study, we analysed the 2018-19 national statistics of 35 cities in China. These 35 construction waste pilot cities generated 1.369 billion tonnes of waste, from which we extrapolated that the national volume was 3.5-4 billion tonnes. This construction waste was mainly soil, and particularly clay, accounting for 70% of the total. A dataset from June 2020 indicates that among these cities, nearly 600 waste utilisation projects were carried out. Their designed capacity was 550 million tonnes/year, with the actual capacity reaching 350 million tonnes/year.
In other words, waste recycling and processing capacity is low, and even then it is underutilised. This is likely a problem not limited only to China. Unlike other countries, however, China has the means to do better. Unfortunately, due to the constraints of the system, including technological, the sector has not fully developed.
It is estimated that in the next few years, China's annual construction waste resource treatment capacity will reach 500-800 million tonnes, of which aggregate will make up 350 million tonnes. Data from 2020 shows that the rate of urban construction waste recycled is only about 10%. Of course, there is still a big gap between China and developed nations, with the EU, for example, having a rate closer to 90%.
Currently, the main targets for utilization are those that affect people's lives or otherwise have a sizeable influence in the overall process, such as concrete, masonry, and other demolition waste. We estimate that this accounts for about 30% of construction waste emissions, and therefore is our focus. In the past, most of this waste simply went to landfill, but now the trend is towards recycling.
Enterprises engaged in this field in China have been doing so since the early 1990s. In the past, they were mainly private enterprises, but they have been gradually transitioning into state-owned or national central enterprises. These enterprises, whether municipal or regional in scale, traditionally neglected the issue of waste recycling. However, many in recent years they have started to become more aware. This has revitalised the sector.
Construction waste recycling and treatment
National regulations
China’s state has attached great importance to the utilisation of construction waste in recent years, producing two main laws.
Construction waste is subject to both these laws.
Since 2015, various ministries and commissions have also put forward a series of documents and regulations concerning construction waste.
o In 2015, the Ministry of Finance issued the "Catalogue of Preferential Value-Added Tax on Products and Labor Services for Comprehensive Utilization of Resources", which includes in particular some of the scrap metals produced by demolition.
o In 2016, the State Council also put forward the comprehensive utilization of urban construction waste in the “Opinions on Further Strengthening the Management of Urban Planning and Construction”.
o In 2019, the Ministry of Industry and Information Technology put forward the standard conditions for the utilization of construction waste resources, and it put forward regulations for enterprises engaged in this industry.
o In 2020, the Ministry of Housing and Urban-Rural Development published "Guiding Opinions on Promoting the Reduction of Construction and Demolition Waste".
Over the years there have in total been over ten national-level regulatory documents.
Local regulations
At the local level, many provinces and cities, including 17 provincial-level administrative regions, have issued guidance or management methods related to construction waste management and recycling. 189 city-level administrative regions have also formulated rules and regulations. About one-third of the country now has stipulated that construction waste should be managed and utilised effectively.
The following table summarises policy documents at all sub-national levels in China,
Industry standards
There are several standards and technical guidance documents that we want to use to promote the recycling of construction waste, one of which being the 2018 "Technical Guidelines for Recycling Construction Waste", prepared by myself, now the industry standard in China. There is also the "Technical Specification for Stationary Construction Waste Disposal" - a series of standards negotiated with our housing and construction and information technology industries. Since 2019, 14 industry and local standards related to construction waste have been promulgated and implemented, including the "Construction Waste Carbon Reaching Peak Carbon Neutralization Path Index System" research, proposed in 2021.
The table below outlines some other relevant national and local standards.
Enterprises engaged in recycling
There are various types of enterprises engaged in recycling construction waste, including private, state-owned, and even China’s relatively large “national central” enterprises. There are naturally then many departments involved in the recycling of construction waste, making supervision difficult.
Local governments have gradually begun to attach great importance to the utilization of construction waste resources, whilst exploring the sector’s modes of operation. It currently depends on a franchise model, which in many cities follows this format:
1. The city's contract is put out by relevant department for public tender.
2. Winning businesses are granted licenses.
3. Construction waste generators apply for licenses.
4. Construction waste transporters apply for licenses.
5. Treatment facilities process the construction waste.
6. Disposal fees are processed, including certain financial subsidies intended to encourage and support enterprises to engage.
Technology
The actual process of recycling construction waste is outlined in the below chart.
Certain technologies are extremely important to the recycling of construction waste, covering classification, separation, vibration-crushing, aggregate-regeneration, and finished product manufacturing. Developed countries provide much of the experience in these areas. Advanced technologies are being continually introduced here in China, in particular those related to environmental protection, dust removal, and air purification functions. AI is also now starting to replace more traditional pneumatic, electromagnet and manual methods of sorting, though it is not yet as comprehensive as required for full adoption. Generally, the technology China uses for construction waste recycling is shared with nations around the world, and can be divided into the below types.
Development prospects
Finally, we will explore the development prospects for this sector.
China’s built environment covers 50-60 billion m², of which 1 billion m² annually is buildings demolished due to aging and other damage. Simultaneously, the total amount of construction waste stored in China now exceeds 50 billion tonnes, and is only increasing each year. The 35 cities in the afore mentioned sample alone contribute an extra 3-5 billion tonnes annually to this figure. But, with China’s annual recycling capacity being only 350 million tonnes (around 7-11%), processing such a gargantuan backlog would take more than 100 years.
Clearly, construction waste needs to be reused more, as the supply is more than adequate. Luckily, China’s demand is also not lacking.
China's urbanisation rate is far from complete, and so the demand of the construction market for materials in considerable. This rapid and continuing urbanisation is driven by the very top, with the recently concluded 20th Congress of the Communist Party of China proposing to build China into an increasingly powerful country, one cornerstone of this defined as being a high urbanisation rate. China’s is currently only just over 60 percent, lower than that of developed countries at over 75-80%. The state will continue to incentivise the population to relocate to the urban areas, and so there will be an obvious need to expand cities and reduce the size of villages, mainly through construction. To complement these new cities, during the 14th Five-Year Plan period, 25,000 Km of new expressways will be built, and an additional one million Km will be resurfaced or otherwise maintained.
One type of material needed in great quantities to build the houses and roads for these future city-dwellers is sand and stone. According to the China Sand and Stone Association, the annual supply should be maintained at about 20 billion tonnes. In the past, this was mainly sourced from dredging and quarrying. However, the state has implemented a national “Double Carbon” policy (the two carbons being “peak” and “comprehensive”), with a focus on key goals of being “people-centred” and protecting “clear waters and green mountains”. Clearly, dredging and quarrying is incompatible with the latter. It is proposed that, to minimise the use of natural resources, a significant proportion of construction waste should be used to satisfy the demand for natural aggregate.
However, it is not only new construction that demands waste to be reused – demand also stems from the state’s desire to better manage natural resources and the environment. By 2022, China's construction waste emissions reached an estimated 3.5-5 billion tonnes. If 90% of this waste could be efficiently reused, around 16.5 million acres of land would be made available, and the natural resources unlocked for other use, reducing the burden on the environment from quarrying and dredging.
Conclusion
The Chinese government has promised to the global community that, although it is a developing country, it will still commit to reach its carbon peak in 2030, and neutrality in 2060. The scale of this task must not be underestimated. China has a large and still rapidly urbanising population, and much infrastructure to modernise to support this, requiring colossal amounts of construction and building materials.
Recycling and resource utilization of construction waste is conducive to carbon reduction and the development of the circular economy, and marries well with the economic benefits of solving the constraints of limited resources and a fragile environment. The reuse of this waste will reduce resource consumption, protect the natural world, and allow the development of an environmentally friendly society.
China’s main obstacle is a construction waste recycling rate much lower than other major global powers – 10%, paling in comparison to Europe’s and US’ roughly 90%, and the 95% of Japan and South Korea. If China can fully utilise its abundant supply, matchmaking it with the significant demand of its increasingly wealthy and urbanised populace, it could unlock economic value estimated to be in the trillions of yuan, which we can all agree should be a strong enough motivator for change.