Estimate Of The Demolition Waste Generation And Its Management Countermeasure By Using Building Lifespan Methods

The large-scale urban renewal and renovation of Shenzhen,especially in the process of buildings'demolition and re-construction,have resulted in a large amount of demolition waste,which has rarely been recycled.The simple treatment and disposal mode of demolition waste-being sent to landfill(dumping)or shipped to neighboring cities-could not only occupy the valuable land resources,but also arouse environmental safety concern.Therefore,scientifically and accurately estimating and predicting the generation characteristics of demolition waste and its spatio-temporal changes is an important basis for strengthening the environmental management of construction and demolition waste,it's also benefits for promoting the sustainable urban development.Based on the literature review and urban planning data analysis,this paper first determines the building floor area of different types of buildings in Shenzhen in past decades.With the help of field investigation(buildings demolition activities)and urban renewal and re-construction plan,actual service lifespan all buildings have been estimated.Meanwhile,a few demolition projects have been selected to conduct on in-depth investigation to gather the first-hand data–determination of the generation rate of demolition waste,waste composition,flows and ultimate disposal in Shenzhen.Furthermore,the demolition waste disposal situation in Shenzhen city in the future is predicted,and the reduction potential and recycling measures are analyzed through scenario analysis.The results show that:(1)the average lifespan expectancy of residential and industrial buildings is 22 years(±7.2)and 23 years(±5.4),respectively,while commercial and public categories are 26 years(±5.2);(2)The generation rate of demolition wastes of residential,industrial,commercial and public building units are 1,612kg/m~2,1,257kg/m~2,1,468kg/m~2 and1,368kg/m~2 respectively;(3)In 2017,the total amount of demolition waste generated in Shenzhen was 13 million tons.In 1979-2016,a total of 98.4 million tons of demolition waste was generated cumulatively in Shenzhen,2017-2036(according to the existing lifespan)will also generate 320 million tons of demolition waste,with an annual growth rate of 27%.According to the current 87%landfill rate,theoretically,14 demolition waste landfills with a capacity of 20 million tons need to be constructed;(4)In fact,if the the designed service lifespan(50 years)is adopt to calculate,the generation of demolition waste in 2017-2036 will be reduced dramatically;(5)In terms of composition,concrete debris accounted for the largest proportion,reaching 50%,followed by masonry waste(22%).Further analysis of the current situation of demolition waste management in Shenzhen shows that the current disposal and treatment method for demolition waste is relatively simple(mainly by landfill);Optimizing urban planning strategies and extending building lifespan can significantly reduce the generation of demolition waste.Meanwhile,there is an urgent need to increase the recycling rate and comprehensive utilization level of demolition waste.The research results of this paper can provide a basis for the optimization of demolition waste management plan and the formulation of waste reduction strategy,so as to improve the environmental management level of construction and demolition waste,promote the sustainable development of urban construction.