Study On Life Cycle Assessment And Carbon Footprint Of Decoration Waste In Megacities

Decoration waste refers to the discarded materials and other wastes generated in the process of decoration of houses that are not subject to construction permit management according to national regulations.It mainly comes from the decoration of residential houses,public buildings,shopping malls,and enterprises and institutions.With the acceleration of urbanization in China,the real estate industry has been developing rapidly,and the residential reconstruction has attracted increasing attention.As the decoration styles are becoming more and more diversified,the degree of decoration is getting higher and higher,and the decoration materials used are becoming more and more complicated,resulting in a large amount of decoration waste.Most of the decoration waste has no proper treatment methods,and is eventually landfill and illegal dumping.Extreme decoration waste treatment methods not only occupy a lot of land resources,causing a waste of resources,but also cause environmental pollution,which has brought a certain impact on the ecological environment.Moreover,it destroys the harmony between man and nature and violates the requirements of the scientific outlook on development.Therefore,how to dispose the decoration waste reasonably,and how to evaluate the environmental impact of the decoration waste disposal process has become a hot topic in the whole society.According to the main disposals,technological characteristics,disposal characteristics and physical and chemical properties of each component of decoration waste in Shanghai over the years,this paper carried out life cycle impact assessment on decoration waste,and set up five scenarios:"landfill"（S1）,"recycling+incineration power generation+landfill"（S2）,"recycling+brick making+aggregate making+incineration power generation+landfill"（S3）,"aggregate making+brick making+landfill"（S4）,and"incineration+aggregate production+landfill"（S5）.The Ga Bi software was used to establish a life cycle assessment model.The emission of pollutants produced by different treatment modes in different stages was quantified.Nine environmental impact types in CML2001-Aug.2016 were selected as evaluation criteria to calculate the characteristic value of environmental impact,obtain the normalized value of decoration waste management life cycle,and compare the environmental impact generated by three treatment modes.The characteristic values of environmental impacts were calculated,and the normalized value of the life cycle of decoration waste management was obtained,and the environmental impacts generated by the three treatment modes were compared.In addition,this paper also adopted the carbon emission factor method to conduct carbon footprint verification at each stage of the five scenarios.The possible carbon emission sources in the waste treatment process were listed in detail,and the electricity consumption or energy consumption of each emission source and the reduction of power generation in the treatment process were calculated.Finally,the net carbon emission in the three treatment modes was calculated and compared.The result shows that:（1）In the life cycle assessment and analysis of decoration waste,in terms of the environmental impact of each scenario,the S1scenario has the largest environmental impact,with a normalized value of 1.62E-08,and the S3 scenario has the smallest normalized value,with a normalized value of6.05E-09,which is 3.7 times less than S1.In terms of environmental impact types,the most significant type that has the most significant impact on the five scenarios is the marine aquatic ecotoxicity potential（MAETP）,which accounts for more than 80%of the total impact.（2）In scenario S3,energy consumption can be reduced due to the recycling of recycled aggregate,recycled bricks and incineration for power generation.On the whole,it can directly inhibit the generation of pollutants,which is the most environmentally friendly way among the five scenarios.In addition,the sale of recycled aggregate and recycled brick can also bring some economic benefits and environmental benefits,which has become an active way to dispose of decoration waste.（3）The environmental impact of each stage is ranked from large to small as follows:landfill>sorting>transportation and unloading>incineration power generation>aggregate bricks.Compared with simply incinerating waste,the use of waste incineration for power generation has a reduction effect and can reduce the consumption of 106,340 MJ of electric energy,which is 641 times the power consumption of the incineration process.Compared with no subsequent utilization,the use of recycled aggregate and bricks instead of natural materials as materials has an offset effect on the environmental impact,which can reduce the consumption of18 MJ electric energy,36 kg diesel oil and 17,696 kg coal.（4）Diesel consumption is the main energy carbon emission source.（5）The net carbon emissions of the five scenarios are ranked from largest to smallest as S1>S4>S5>S2>S3,and S3 generates292%less carbon emissions than the S1 scenario.Incineration for power generation,aggregate recycling and reuse,and aggregate brick-making processes as sinks to reduce greenhouse gas amounts generated by landfill and other processes are3.07E+04 kg-CO₂eq,1.17E+02 kg-CO₂eq and 2.86E+04 kg-CO₂eq,respectively,which are 1.78,0.0068 and 1.66 times the carbon emissions of 1 ton of decoration waste from landfills.（6）As far as the treatment stage is concerned,landfill is the stage that contributes the most to carbon emissions in the S1 scenario,accounting for 96.2%of the total.Power generation by incineration is the main measure to reduce carbon emissions in decoration waste disposal.In scenarios S2,S3 and S5,carbon emissions can be reduced by 3.07E+04 kg-CO₂eq,which is equivalent to reducing power emissions by 2.95E+04 k W·h.The aggregate brick production stage can reduce the energy and matter consumed by natural brick production,and in the S4 scenario,it can reduce the carbon emission of 2.87E+04 kg-CO₂eq,which is equivalent to reducing the electric power emission of 2.76E+04 k W·h.