| Construction solid waste has characteristics of its complex composition with huge amount.Recycling and reuse are directions for its treatment and disposal.Classified collection of construction solid waste in accordance to material category is the premise for its resource utilization and harmless disposal.It is a research hotspot to develop new technologies for treatment and resource utilization of construction solid waste.In this paper Fuzhou City was employed as a case to research and analyze the resource utilization of urban construction solid waste.Firstly,based on the influencing factors of regional building material metabolism,the dynamic material flow analysis(DFMA)method was established for the building system by employing the whole life cycle analysis(LCA)as the benchmark frame.Basically,The relationship of existing buildings and building solid waste changes with the temporal and spatial variation was investigated.And the evaluating method of the material input/output intensity of building system in a specific area over a specific period.The results provide a theory for the transformation and high-quality utilization of urban construction solid waste into building materials,reducing carbon emissions in the construction industry,and improving resource utilization.Secondly,combining the dynamic material flow theoretical model of the building system with the improved grey prediction model,the building system in Fuzhou was taken as a case,the increment and inventory of building was analyzed.Moreover,the input/output mass flow amount of buildings in Fuzhou from 1950 to 2050 was estimated.The results show that,with the improvement of people’s living standards and the large influx of foreigners,the demand for housing construction in Fuzhou urban areas increases rapidly,the number of new buildings,demolition and renovation projects of old houses increases sharply,and the material input and output of the building system increase significantly.According to the trend analysis results of demolition garbage and new construction area,it can be seen that the accumulation efficiency of buildings under the development mode of large demolition and large construction is low.Although it can play a certain role in improving the city,it will cause serious damage to the environment.This behavior must be obtained.The key to increasing the accumulation efficiency of buildings and improving the urban environment is to promote the technology of strengthening and prolonging the life of buildings.The research on the amount of demolition waste has shown that under the same building stock trend,the extension of the building life will reduce the amount of demolition waste exponentially.If the building life is extended to 50 years,the demolition waste can be reduced by more than half.From the calculation results,the total output of building solid waste will reach 7.0×10~8tons in Fuzhou in 2050,among which the solid waste from demolition construction will account for 85.9%.This will put enormous pressure on resources and the environment,and the promotion and promotion of construction solid waste recycling is imminent.Finally,on the basis of the constructed environmental analysis cost accounting framework,the green ceramsite project with consumption of 1.5 million tons of construction solid waste in Fuzhou was employed as an example to analysis its environmental cost.It is clear that the environmental benefit of reducing the transportation distance is 66,700 yuan/a.The environmental benefit of replacing natural building materials is 4.31 million yuan/a,the environmental benefit of reducing landfill is82.8 million yuan/a,and the environmental impact cost during the operation of the project is 18.61 million yuan/a.The total environmental benefit of the project after accounting is 68.56 million yuan/a.The results show that the resource utilization project has significantly improved the environment,but the environmental pollution during the operation of the project is still relatively serious.Therefore,vigorously developing the resource recycling industry is an important way to build an intensive society,and further improving the level of resource recycling technology is the key to reducing environmental costs. |
