Development of a comprehensive environmental guidance and sustainability assessment for different organic fraction of municipal solid waste-to-biofuel scenarios based on life cycle analysis

Abstract

The environmental impact assessment of organic fraction of municipal solid waste (OF/MSW)-to-biofuel structures is essential prior to scaling them up to identify worrisome impacts on ecosystems, resources, human health, and climate. The current article aims to address a sustainable and comprehensive guide for analyzing the environmental impacts (based on the life cycle analysis (LCA)) of different OF/MSW-to-biofuel structures. To analyze different structures, three pre-treatment procedures (namely, hot water/acetone organosolv/acid), two different hydrolysis treatment ways (acidic/enzymatic), and different fermentation alternative methods (ethanolic/acetone-ethanol-butanol fermentations) were considered. The findings of the research indicated that scenarios based on acetone-ethanol-butanol fermentation cannot address a favorable environmental performance (due to the insufficiency of the avoided effects of the output products to compensate the environmental burdens caused by acetone pre-treatment). In contrast, scenarios based on ethanolic fermentation integrated with hot water or acid-based pre-treatment process can address superior environmental performances compared to scenarios based on acetone-ethanol-butanol fermentation and ethanolic (with acetone pre-treatment). Comprehensively, Scenario S-4 (as most eco-friendly Scenario) yielded the greatest net environmental savings with reductions of −857.16 potentially disappeared fraction/m2 per year, −214.3 kg CO2 equivalent per ton of/MSW, and −3.33 GJ per ton of/MSW processed.