Critical review on life cycle assessment of conventional and innovative waste-to-energy technologies

Felix Mayer; Ramchandra Bhandari; Stefan Gäth

doi:10.1016/j.scitotenv.2019.03.449

Critical review on life cycle assessment of conventional and innovative waste-to-energy technologies

Sci Total Environ. 2019 Jul 1:672:708-721. doi: 10.1016/j.scitotenv.2019.03.449. Epub 2019 Apr 1.

Authors

Felix Mayer¹, Ramchandra Bhandari², Stefan Gäth³

Affiliations

¹ Institute for Technology and Resources Management in the Tropics and Subtropics, TH Köln (University of Applied Sciences), Betzdorfer Strasse 2, 50679 Cologne, Germany. Electronic address: felix.mayer1@th-koeln.de.
² Institute for Technology and Resources Management in the Tropics and Subtropics, TH Köln (University of Applied Sciences), Betzdorfer Strasse 2, 50679 Cologne, Germany.
³ Department of Agricultural Sciences, Nutritional Sciences and Environmental Management, Justus-Liebig-University, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany.

PMID: 30974361
DOI: 10.1016/j.scitotenv.2019.03.449

Abstract

In this study 315 peer-reviewed studies on environmental life cycle assessment (LCA) of waste-to-energy (WtE) technologies were critically analysed. The technologies considered were anaerobic digestion, hydrothermal carbonization, pyrolysis, gasification and incineration. It was found that overall increasingly more studies are concerned with LCA on waste-treatment systems. Although incineration and anaerobic digestion were primarily assessed, especially in recent years, a growing number of LCA-studies investigated advanced thermal treatment options. The geographical scope within the studies under review focused mainly on European (195 studies) and Asian (68 studies) regions. In regards to their quality, a majority of the analysed studies were marked by several shortcomings and showed poor compliance with the ISO 14040 and ISO 14044. 55 studies did not present a functional unit and >45% of all reviewed studies did not present a life cycle inventory. More than 50% of the reviewed studies omitted a sensitivity analysis and a comprehensive assessment of all impact categories was not present in most studies. By selecting studies that analysed two or more different WtE treatment options, the global warming potential and the acidification potential of the considered five different technologies were compared. By contrasting advanced treatment options against incineration, substantial environmental benefits of advanced treatment options could not be observed. However, only 34 studies fulfilled the criteria to be taken into account for this comparison. The main finding within this scope, was that anaerobic digestion and gasification seemed to outcompete incineration in the conversion process of waste. Cascaded waste treatment, i.e. combining several treatment technologies, was only present in few studies. Environmental benefits could be assigned to these treatment paths in most cases. Lastly, techno-economic aspects are highlighted and appropriate policies are deducted from the obtained results.

Keywords: Advanced waste treatment; Cascaded waste treatment; Ecological life cycle assessment; Energy recovery; Waste-to-energy.

Publication types

Review