Comparative streamlined life cycle assessment for two types of municipal solid waste incinerator

Abstract

Abstract This study is a comparative streamlined life cycle assessment (CSLCA) for two types of solid waste incineration technologies, the fluidized-bed incinerator (FBI) and the mechanical-grate incinerator (MGI), both of which are commonly used in East Asia and Europe for burning similar composition municipal solid waste. Different consumption levels of energy and/or materials within the streamlined process were thoroughly evaluated for comparison, but disposal of incineration ashes and emissions from landfills were excluded. Within this context, one tonne of municipal solid waste (MSW) was chosen as the functional unit to support our inventory items in this study. To improve the reliability of our CSLCA both Eco-indicator 99 and ReCiPe assessment methods were selected for environmental performance evaluation based on designated life cycle assessment indicators. Through the use of life cycle inventory and impact assessment tools, the environmental impacts were collectively assessed for possible damage to human health, ecosystem integrity, and resources. Finally, a generalized numeric scheme was produced for the overall assessment. The weighted values of environmental impacts associated with MGI and FBI, respectively, were 0.047 and 17.91 Pt per kg waste incinerated based on Eco-indicator 99 and, in contrast, 47.47 and 45.03 Pt per kg based on ReCiPe. Overall, the fluidized-bed incinerator is deemed environmentally benign in a relative sense based on the CSLCA in this study. Concerning human health, ecosystem integrity, and resources, the environmental impact associated with human health is the most critical for both types of incinerators. This finding is evidenced by both assessment methods of Eco-indicator 99 and ReCiPe, albeit the two methods are not compatible. Further observations also helped identify two sensitive parameters, including carbon dioxide (CO2) emissions and electricity consumption across the two incineration technologies. Such a study helps identify the least burdening option for constructing municipal solid waste incinerators to meet the goal of urban sustainability.