Carbon emission reduction potential of low-value recyclables classification and treatment in municipal solid waste

The classification and management of municipal solid waste (MSW) from residential areas is a significant source of urban greenhouse gas (GHG) emissions. The sorting of low-value recyclables (LVR) in MSW contributes to the achievement of waste reduction and the maximum utilization of resource, playing a critical role in the development of an environmentally friendly and resource-efficient society. This study took the pilot community of LVR classification in Xiamen as a case study, analyzing the composition, carbon emission characteristics, and carbon reduction potential of residential waste low-value recyclables based on the IPCC inventory guidelines. The results of the study indicated that: ① Diverse economic levels resulted in significant differences of LVR composition between communities, where plastic waste comprises the highest proportion (52.62%～58.40%), followed by paper (16.42%～19.29%) and glass (8.80%～11.58%), with the remainder being ceramics, textiles, and impurities.②In accordance with different scenarios that were based on LVR sorting rates, net carbon emissions (measured in CO₂-eq per ton of LVR) decreased from 645.86 kgCO₂-eq/t to -374.24 kgCO₂-eq/t as the scenario changed from scenario one (incineration + landfill) to scenario four (30% LVR recycling).③Uncertainty analysis shows that an 8% increase in incineration energy efficiency and a 20% reduction in product substitution from recycling led to a reduction of 239.15 kgCO₂-eq/t and an increase of 172.56 kgCO₂-eq/t, respectively, in scenario four.④When the residual waste incineration amount reaches 1,613,700 tons,  30% LVR recycling from residual waste is able to cause 927,000 tons of carbon  emission reduction .