Study On The Generation Amount Prediction And Recycling Of Large-scale Demolition Waste

A large amount of demolition waste is produced in the urban renewal process,although with economy growth and urban competitiveness enhancement.Not only does the extensive management of demolition waste occupy enormous land resources,but also brings tremendous pressure to urban environmental supervision.Therefore,it is an urgent problem to be solved that how to effectively manage demolition waste generated during large-scale urban renewal.Accurate prediction of demolition waste generation and scientific estimation on recycling potential are both considered important prerequisites for effective demolition waste management.However,the existing studies fail to predict the generation of large-scale demolition waste and estimate its recycling potential quickly,accurately and efficiently,owing to the lack of basic data and information technology.Firstly,this study systematically summarizes the existing prediction methods of demolition waste generation.Prediction based on waste weight per floor area is considered an effective method to predict demolition waste generation during large-scale urban renewal.A prediction model is subsequently proposed based on two indicators of waste generation rate(WGR)and gross floor area(GFA).Then,this study comprehensively summarizes the existing acquisition methods of these two indicators.WGR could be accurately measured based on on-site measurement and the existing industrial standard data,while GFA could be obtained based on image recognition technology and Google Earth with high efficiency.Next,this study analyzes main paths and key links of demolition waste recycling,based on which,the key information and basic data indicators involved in each major path and each key link are clarified with methods of the on-site investigations of 36 demolition waste recycling enterprises in Shenzhen and the semi-structured interviews with 51 major stakeholders.Demolition waste fixed process flow model and mobile process flow model are accordingly established.Furthermore,the non-inert and inert demolition waste recycling potential estimation model are established based on economic benefits and mass conservation,respectively.Finally,509 urban renewal projects in Shenzhen are taken as a case study to predict the generation amount,composition,and proportion of demolition waste during large-scale urban renewal in Shenzhen,with the recycling potential estimated.As is shown in results,(1)different WGRs depend on buildings types and structure types.Old town area is the largest(Mean=1369.51 kg/m~2)among three kinds of building types,with urban village(Mean=1254.66 kg/m~2)and old industrial area(Mean=1114.86 kg/m~2)followed.As for structure types,frame structure has the largest WGR(Mean=1312.03 kg/m~2),followed by frame-shear structure(Mean=1214.91 kg/m~2)and brick-concrete structure(Mean=1212.09kg/m~2).(2)the major compositions of demolition waste include concrete,brick/block,mortar,steel,ceramic,aluminum,plastic,granite,glass,copper and timber.(3)demolition waste recycling disposal methods are mainly divided into fixed disposal and mobile disposal,and there are large differences between them.(4)different recycling potential depend on demolition waste types.(5)49.42 million tons of demolition waste may generate during large-scale urban renewal in Shenzhen.Concrete waste peaks the largest amount at 24.07million tons among major compositions,and brick/block contributes the second largest amount at 15.85 million tons.Following are mortar and steel waste,with 4.89 million tons and 1.79 million tons,respectively.These four types of waste account for 94.28%in total.The recycling potential of non-inert demolition waste is RMB 21.30 billion yuan.The recycling potential of inert demolition waste is 18.39 million tons of recycled bricks,7 million tons of recycled mortar and 28.32 million tons of recycled aggregate.Findings of this study improve scientificity and accuracy of the existing prediction methods and estimation methods for large-scale demolition waste.The methods proposed in this study,such as large-scale demolition waste generation prediction method,WGR measured method,GFA acquisition method,and demolition waste recycling potential estimation method could be generally applied in other regions.The basic data indicators measured in this study could be used for research in Shenzhen and other similar regions.In addition,the current research provides valuable reference for government departments in planning the amount,location and scale of demolition waste recycling enterprises and landfills.Besides,it provides basic data and decision support for further tailored policies of demolition waste management.