Alteration of biomass toxicity in torrefaction: A XDS-CALUX bioassay study

Łukasz Sobol, Arkadiusz Dyjakon, Marek Korendał, Marzena Styczyńska, Dominika Sabat, Antoni Szumny, Bogdan Z. Dlugogorski

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Torrefaction constitutes one of the promising technologies for the management of waste biomass and the production of high-carbon products for combustion, gasification, adsorption of pollutants or soil treatment. Unfortunately, waste biomass may be contaminated with toxic persistent organic pollutants, such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF) and dioxin-like biphenyls (dl-PCB). Literature does not provide consistent measurements on how the low-temperature thermochemical processing, such as torrefaction, affects the toxicity of biomass. This contribution assesses how a torrefaction treatment, conducted at 200 °C, modifies the toxicity due to PCDD/PCDF/dl-PCB in biomass. We deploy the XDS-CALUX biotest on five types of waste biomass (sewage sludge, tree bark, cattle manure, spent coffee ground, common reed), before and after treatment. The content of total dioxin- & biphenyl fraction compounds in the raw biomass, investigated in this study, varies from 0.14 to 3.67 pg BEQ·g−1d.m., and in the torrefied biomass between 0.17 and 6.00 pg BEQ·g−1d.m.; BEQ stands for bioanalytical equivalent. This increase is statistically insignificant at p = 0.05, taking into account all types of examined biomass. This proves that low-temperature torrefaction cannot detoxify biomass, i.e., chars, produced from biomass characterized by elevated concentration of PCDD/PCDF/dl-PCB, will reflect the contamination of the feedstocks. With respect to heavy metals, we conclude that only the content of Cd in biomass, and, to a lesser extent, the abundance of Cu and Fe, modify the toxicity of this material during its thermochemical treatment at low temperature.

Original languageEnglish
Article number141258
Pages (from-to)1-10
Number of pages10
Publication statusPublished - Mar 2024

Bibliographical note

Funding Information:
The publication is financed under the individual student research project “Młode umysły—Young Minds Project” from the subsidy increased for the period 2020–2025 in the amount of 2% of the subsidy referred to Art. 387 (3) of the Law of 20 July 2018 on Higher Education and Science, obtained in 2019. This research was funded/co-founded by Wrocław University of Environmental and Life Sciences , grant number N010/0010/22 . The APC is financed by Wrocław University of Environmental and Life Sciences.

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