Environmental Impact Analysis Of Solid Waste Energy Conversion Based On Life Cycle Assessment Method

Human production and living activities generate a large amount of solid waste.Municipal solid waste and sewage sludge are important solid wastes.They are widely sourced,processed,and have many components with bad effects on water,air and soil.At present,the harmless treatment rate and resource utilization rate of waste and sludge in China are low,and the treatment level is insufficient.Especially the secondary pollution has become a hot spot of social concern.Models and methods to study the environmental impact of waste and sludge can provide important scientific support for sustainable Municipal solid waste and sewage sludge management.This paper applies a sustainable environmental management tool-life cycle assessment software Simapro,which compares the environmental impact of the linear addition of waste and sludge incineration with the environmental impact of waste and sludge mixed incineration to calculate the environmental load,explore the environmental impact mechanisms behind waste disposal,and identify key pollutants.The main conclusions are:?1?Compare the two most commonly used life cycle assessment methods in Simapro software:Impact 2002+and Recipe endpoint2016.The Impact2002+method includes 17 categories of intermediate evaluation index,and the Recipe endpoint2016method includes 15 categories.The main differences are climate change and land use.The Impact2002+method endpoint damage category includes four categories,namely,DALY?unit:Disabillity Adjusted life year?,and ecological quality?unit:PDF*M2*yr,PDF:Potentially Decrease Fraction.It stands for the amount of loss of a species in a particular area,in a given period of time?,resource consumption?unit:MJ?and climate change?unit:kg CO₂ eq?.Recipe endpoint 2016 method only includes three categories.In addition to the unit of human health,the other two units of ecological quality and resource consumption are inconsistent.The ecological quality in the Recipe endpoint2016 method is also evaluated by the number of species losses,but there is no specified area,and the resource consumption is in US dollars.?2?Although the evaluation units of the two methods are mostly different,the comparative results show that no matter which method is used for evaluation,the environmental effects of mixed incineration show positive effects,and the separate incineration shows negative effects.The impact on human health is not much different.It shows that the negative environmental effect caused by incineration alone is about 4times that of mixed incineration,the difference is the impact on ecological quality.The Impact 2002+method shows that the negative effect of individual incineration is small,accounting for only 0.35%of the positive effect of mixed incineration,while the negative effect of incineration evaluated by the Recipe endpoint 2016 method is about four times that of the mixed incineration.For resource consumption index,the Impact2002+method shows that the negative effect of separate incineration is about 8times that of the mixed incineration,while the negative effect of the separate incineration evaluated by the Recipe endpoint 2016 method is about twice the positive effect of the mixed incineration.The unit of the endpoint2016 method is currency,which leads to the evaluation result being affected by factors such as price,and the uncertainty is more significant.Therefore,the Impact 2002+method is more reasonable and comprehensive for the evaluation of climate change and resource utilization,and is applicable to the environmental impact assessment of solid waste energy.?3?The results of the evaluation of Impact 2002+method in Simapro software show that the mixed waste incineration treatment has the least impact on the environment,especially in terms of climate change and resource consumption.The total environmental impact is 6 times and 8 times smaller.This is mainly because the electricity required for drying sludge in the mixed waste incineration project is directly supplied by electricity and heat generated by waste incineration.It does not consume electricity and heat from the external network,and saves fossil energy,reduces carbon dioxide and other Emission of atmospheric pollutants.Although the results of this study have yet to be refined,they basically reflect the life cycle environmental impacts of municipal solid waste and sewage sludge.From the perspective of environmental management,this study has a reference role for the government to determine the urban waste and sludge treatment methods.