Environmental Benefits Evaluation Of Urban Industrial Symbiosis System Based On LCA

Urban industrial symbiosis is an important mode for the development of regional circular economy and the construction of“no-waste city”in China.Through the internal products and the by-products of industrial systems and urban systems,waste exchange and reuse,the effective use of regional resources can be realized,and it can also reduce waste production and environmental impact.An objective and scientific evaluation of the environmental benefits of the urban industrial symbiosis system can effectively evaluate the level of urban industrial symbiosis system construction,understand the importance of various factors to the construction of urban industrial symbiosis system,and provide a basis for urban management and decision-making.Dalian has a strong industrial base and is also an important shellfish culture area in China.Therefore,we took Dalian as the research object.Firstly,we studied the utilization of shellfish resources in Dalian and chose the best way of reusing shell resources.Then,we identified the existing symbiotic scenarios of Dalian,and increased the virtual symbiosis scenarios that could be implemented,then constructed the urban industrial symbiosis system of Dalian.It evaluated the environmental benefits of the system by using LCA.It provided theoretical guidance and technical support for the development of circular economy and the construction of“no waste city”.The main research contents and results of the thesis are as follows:?1?Selection of shell resources utilization methods in Dalian.In view of the shortcomings of the development and utilization of shell waste in Dalian,this study evaluated the environmental impact of conventional treatment methods of shells and three resource utilization methods of shells by using life cycle assessment methods to compare the differences in the environmental impacts such as Chinese abiotic depletion potential,global warming potential and so on.The results showed that when the function unit was 1 kg shell,the environmental impact of scheme 0?landfill?was 1.04E-14;the environmental impact of scheme 1?instead of limestone in cement production?was-3.78E-12;the environmental impact of scheme 2?instead of the ceramsite filler in the immersion biofilter column?was-1.85E-14;the environmental impact of scheme 3?instead of sand as building material?was3.62E-14.Compared with the other three schemes,scheme 1 had better environmental benefits.So scheme 1 was selected as the resource utilization method for shells in Dalian.?2?Environmental benefit evaluation of urban industrial symbiosis system in Dalian.This study constructed a perfect urban industrial symbiosis system in Dalian by identifying existing symbiotic scenarios in the symbiotic system and designing a viable virtual symbiosis scenarios.This research integrated LCA with system expansion to evaluate the environmental impacts of the symbiosis system,and the eBalance software was used to model and calculate.The results showed that the environmental impacts avoided by the urban industrial symbiosis system in Dalian included 1.17E+07 kg SO₂e acidification gas,2.98E+09 kg CO₂e greenhouse gas,1.38E+11 kg fresh water consumption,and 9.22E+09 kg Coal-Re resource consumption,4.89E+06 kg COD emissions,3.13E+06 kg PO₄^3-e eutrophication,3.85E+06 kg PM2.5e respirable inorganics,1.54E+09 kg solid waste,3.75E+10 MJ Energy consumption.The environmental impact value of the symbiotic system is-2.94E-02,which had positive effects on the environment.The type of environmental impact that contributed the most to environmental impact values was Waste Solid?WS?,followed by Chinese Abiotic Depletion?CADP?.The benefits of all symbiotic scenarios were positive for the environment,and scenario 13 brought the greatest environmental benefits.