Comparative study of municipal solid waste incinerator fly ash reutilization in China: Environmental and economic performances

Harmless disposal and reutilization of municipal solid waste incinerator fly ash (IFA) attract growing interests due to the gap between increasing IFA generation and limited landfill space. Therefore, an economical-affordable and environmentally friendly approach to deal with IFA is required. Herein, major IFA reutilization technologies in China (IFA-to-cement, glassy slags, rock wool, and ceramsite) were evaluated and compared with the landfill using life cycle assessment (LCA) and environmental life-cycle costing (eLCC). Prior to assessments, material flow analysis (MFA) was used to establish a heavy metal transfer coefficient model. LCA results indicate IFA-to-cement and IFA-to-ceramsite outperform others while eLCC results show that IFA-to-ceramsite and IFA-to-rock wool are preferred, breaking even at years 3 and 5 compared to IFA-to-cement (new plant) at year 11. To reveal true costs of reutilization technologies, whole life costing (WLC) was applied to include externality costs via monetizing emissions. Major pollutants contributed to externality costs of these technologies were identified. IFA-to-ceramsite and IFA-to-rock wool technologies remain preferred with payback time as 4 and 6 years respectively. A scenario analysis suggests that replacing sintering aids with polluted soil and Sec-FA recovery could further improve the overall performance of IFA-to-ceramsite option. Policy scenario analysis reveals that corporate income tax and environmental protection tax have negligible impacts but waste disposal subsidy is vital for IFA reutilization technologies being economic feasible even without externalities.