Study On The Characteristics Of The Generation And Management Of Construction And Demolition Waste In China

China is still in the stage of rapid urbanization.Due to the scarcity of urban land resources,the large-scale demolition and urban renewal of urban area is becoming an important mode of construction activities instead of urban expasion.However,large-scale urban construction and renwal activities will make the whole building "razed to the ground" quickly,which will bring a lot of construction and demolition(C&D)waste.At present,landfill disposal of C&D waste will not only encroach on valuable land resources,but also bring great pressure on the ecological environment.At the same time,these wastes are also a great waste of renewable building materials.Therefore,it is of great significance to estimate the volume,trend,and study the management of C&D waste scientifically and reasonably,which will make feasible strategies for C&D waste management and planning.Firstly,a series sruveys of construction,renewbal and renovation activities have been conducted,which could identify different types of newly building,renovation and demolition wastes,study the generation characteristics and material composition,and obtain the on-site data.Secondly,in terms of the principles of “generation source,flows and amount” of Materaisl Flows Analysis(MFA)theory,three typical approaches have been put forward to arrive the accurate estimates:(1)Weight-per-construction-area method,using construction and demolition floor area data with waste generation rate(per floor area)data;(2)buildings' lifespan-based method,using the buildings floor area(stock)data and their average lifespan;(3)Records-based accounting,combining major cities' C&D wastes generation per capita estimates with urban population data across all cities,total national quantities of generated C&D wastes.The methods were conducted to quantitatively estimated and systematically analyzed the generation,material composition and flow management characteristics of C&D waste in China.The total amount,material composition and flow management characteristics of construction waste in China are quantitatively estimated and systematically analyzed.The results show that the total amount of C&D waste generation in China is estimated to be 2-3 billion tons through three quantitative methods.Taking the weight-per-construction-area method as an example,demolition wastes are the largest part of C&D waste(accounted for 77%),which generated 2.4 billion tons in 2015;construction waste generated about 440 million tons,the rest is renovation waste(280 million tons).From the study of C&D waste flow analysis,metal recovery rate is the highest,which close to 100%.Followed by plastic and paper materials,which reach to 97% and 92%,respectively.However,the recycling rate of brick and concrete,which are the most part of C&D waste,could only reach to 3.8% and 1.9 respectively.Finally,based on the investigation of the generation,flow,recycling technology and energy consumption of C&D wastes,the environmental effect was evaluated by this paper.Overall,based on much investigations,and combining the method and idea of material flow,this paper studied C&D waste genenration characteristics and flow management,the results can provide the basic data for management of C&D waste,and provide a methodological reference for regional or national scale C&D waste quantitative analysis.