A Life Cycle Assessment of Flue Gas Treatment Technologies for Municipal Solid Waste Incineration in China: Cost and Environmental Benefits and Regional Adaptability

To balance environmental compliance and industrial sustainability in flue gas treatment from waste incineration, this study systematically evaluates the application patterns and environmental-economic impacts of eight mainstream technologies based on survey data from more than 300 incineration plants across China. Findings indicate that Selective noncatalytic reduction + semidry + dry + activated carbon injection + bag dust + selective catalytic reduction constitutes the dominant configuration nationwide (accounting for over 50%). Research indicates that the T6(Selective noncatalytic reduction + semidry + dry + activated carbon injection + bag dust + selective catalytic reduction + wet), demonstrates optimal performance across multiple environmental metrics. Considering both operational costs and external costs, the T6 process costs 87.9 CNY, making it the most cost-effective option. Notably, following the implementation of the T6 replacement, NOX emissions will decrease by 8.2 × 104 tons, and SO2 emissions will decrease by 3.87 × 104 tons. It also exhibits the lowest values across key performance indicators such as global warming potential (GWP), primary energy demand, and water use, resulting in the smallest indirect emissions. Scenario simulations indicate that promoting technological iteration effectively reduces acidification potential (AP) and GWP. Scenario 3, featuring T6 replacement, achieves optimal emission reduction efficiency, reducing 2.16 × 104 tons SO2 eq and 2.01 × 105 tons CO2 eq. However, GWP exhibits a complex pattern of rising initially and then declining during this process due to the combination of multiple methods and the use of chemical agents. Furthermore, technology upgrade pathways must be tailored to city scale: first-tier cities with annual incineration volumes exceeding one million tons demonstrate significant economies of scale, while smaller towns require cross-regional collaboration to control costs. This study ultimately provides critical scientific support for developing differentiated technology upgrade strategies to achieve the synergistic goals of pollution reduction and carbon mitigation.