Construction and demolition waste management: China's lessons
'Solid waste production must peak this century without drastic action, population growth and urbanization will outpace waste reduction' warned by Hoornweg et al. (2013) A stark example of this prediction occurred in Shenzhen, China, on 20 December 2015, where an unstable deposit of construction and demolition (C&D) and other wastes catastrophically collapsed (Xu et al. 2015) The landslide buried nearly three dozen buildings and left at least 75 people missing, arising from the piling of C&D waste and other wastes. This dramatic situation illustrates that China is facing big challenges for managing C&D wastes with substantial urban development throughout the country. China's construction industry is expected to continue its considerable growth for the foreseeable future. In recent years, large scale urban construction programmes, particularly the extensive urban renewal activities in big cities, have produced billions of tonnes of C&D waste, and caused significant environmental impacts. A report from National Development and Reform Commission of China claims that China generated roughly 1 billion tonnes of C&D waste in 2013, which was five times more than the amount of municipal solid waste generated in China in the same period. However, only about 5% of the C&D waste was reused or recycled. Another report, released by the China Strategic Alliance of Technological Innovation for Construction Waste Recycling Industry, revealed that the quantity of C&D waste was expected to be 1.55 to 2.50 billion tonnes per year, which is two to three times higher than the total C&D waste generation in the entire European Union (25 counties) The residual (unrecoverable) C&D materials usually end up in landfills after manual separation and full recycling of metals and intact building materials. However, some building owners, demolition contractors, and waste collectors disposed of this waste improperly at unlicensed dumping sites to avoid high transportation costs and landfilling fees charged by regulated (formal) waste disposal facilities. It was found that waste dumping sites included gravel pits, farm land, abandoned residential land, borrow pits, and low lying areas (Xu et al. 2015) The countermeasures of C&D waste in China, ranging from collection, transportation, treatment to ultimate disposal, is incomplete in comparison with municipal solid waste. A few cities with developed economics, such as Beijing, Shanghai, and Shenzhen, have indeed taken actions to manage the C&D waste, however, the existing C&D waste management regulations are not rigid and are unenforceable in supporting the minimisation and environmentally sound management of C&D waste. Take Shenzhen city for example, it is a leading city in southern China for C&D waste management. The total generation of C&D waste reached 35 million tonnes in 2014, of which 16% was sent to seven recycling plants for reuse. The other 84% was disposed of by landfill. However, there were only six licensed landfill sites, which had an extremely limited capacity (approximate 10 million tonnes) to accept the C&D waste. This implies that over half of the C&D waste in 2014 was disposed of in unlicensed landfill sites or bydumping. Currently, the local government is making attempts to reclaim the land from sea by using C&D waste, which could probably arouse controversy owing to marine environmental damage and geological security. While the vast majority of construction materials are inert and managed as non hazardous wastes, buildings may either have used some environmentally unfriendly substances, or probably absorbed harmful elements, such as heavy metals. In general, 'clean C&D wastes' suitable for recycling or reuse (i.e. that which was not contaminated by heavy metals) includes the following scarp materials: broken concrete, bricks, rock and stone, and soil. C&D waste mixtures, which include plastic, paper, foam, wood, or other substances, likely would introduce contamination by heavy metals, particularly zinc. Therefore, the removal of surface materials is indispensable before recycling or other treatment activities. Brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) have been widely used in a variety of commercial and consumer products. The interest in BFRs from an environmental point of view has increased considerably during the last two decades. PBDEs and HBCD are currently being considered under the framework of the Stockholm Convention on Persistent Organic Pollutants (POPs) owing to their persistence in the environment, bioaccumulative capacity, and toxicity. At present, PBDEs in the environment are the most commonly studied BFRs, whereas data on the environmental concentrations of HBCD are scarce. Building materials also probably contain PBDEs and HBCD, used as a fire retardant. The distribution of HBCD and PBDEs in C&D wastes could be influenced by usage of polyurethane (PUR) foam materials. In particular, there is relatively little work to characterise the POPs in C&D waste. Additional risks related to C&D waste include asbestos removal. Asbestos has already been identified as a great threat to human health, because these fibres can be inhaled into the lungs and cause cancer and other lung diseases. Many old buildings that are entering the end stage of life in China contain asbestos. While asbestos used as building material has been phased out in many developed countries, and there are rigid and enforceable Construction and demolition waste management: China's lessons 647603WMR0010.1177/0734242X16647603Waste Management ResearchEditorial research article2016
Waste management research the journal of the International Solid Wastes and Public Cleansing Association, ISWA