Carbon reduction efficiency of community domestic waste separation at source and comprehensive treatment system under compulsory classification

Abstract

[Objective] In the context of compulsory classification, different source separation and collection methods will change the flow direction of municipal solid waste and the subsequent collection and disposal process, and then affect the life cycle carbon emissions and economic performance of the recycling system. According to the different scenarios of Beijing community garbage source classification and comprehensive treatment system, this study carried out carbon reduction efficiency analysis and optimization, in order to provide a scientific basis for the establishment of garbage classification and collection model according to local conditions. [Methods] The material flow analysis method (MFA) was used to analyze the material flow direction and flow in the whole process of recycling and treatment, and evaluated the carbon footprint and economic cost respectively with life cycle carbon emission accounting (LCCA) and life cycle cost analysis (LCC) methods. On this basis, a carbon reduction efficiency index was put forward and optimized. [Results] The life cycle carbon emissions of the baseline scenario (S1) and the optimization scenario (S2-S5) are -148.14 kgCO2e, -236.44 kgCO2e, -251.25 kgCO2e, -297.06 kgCO2e, -343.51 kgCO2e, respectively. Compared with S1, the four optimization scenarios show positive carbon reduction efficiency, and the carbon reduction efficiency values are S5 (2.20)>S4 (1.66)>S3(1.38)>S2 (1.31). Scenario 5 corresponding to the “garbage sorting station+recyclable intelligent recycling bin+garbage classification instructor” optimization model has the highest carbon reduction efficiency. Under the premise that the comprehensive treatment capacity of domestic waste and the treatment capacity of each component are sufficient, with the increase of the proportion of accurate classification, the carbon reduction efficiency is gradually improved. [Conclusion] The establishment and improvement of the source separation and collection system increases the front-end infrastructure operation cost, labor cost, and environmental impact, but effectively improves the back- end classification and treatment efficiency and the output rate of renewable resources, resulting in the improvement of life cycle carbon emission reduction benefits. With the increasing participation rate and accuracy of domestic waste classification in the future, the cost in the collection stage will be greatly reduced, and the carbon reduction efficiency can be further improved.

Keywords

• |municipal solid waste|waste classification|material flow analysis|life cycle assessment|life cycle cost|carbon reduction efficiency|beijing