Solid biofuels properties of Miscanthus X giganteus cultivated on contaminated soil after phytoremediation process

Abstract

Following the objectives of the 2030 climate and energy framework as well as the European Green Deal strategy to 2050, renewable energy sources have been defined as an important factor in the process of climate change mitigation. Renewable energy sources are the basis of the aspirations of the EU to achieve low-carbon energy self-sufficiency. Under the classification of renewable energy sources biomass obtained by cultivating energy crops is also included. In order to avoid collisions between energy production and food/feed production, the cultivation of energy crops should be based on marginal soils, which also include soil contaminated by heavy metals. The use of energy crops in the process of phytoremediation is a multifunctional methodology that manifests itself through the cleaning of contaminated soil with the biomass production. The usefulness of using certain biomass types in the ignition process is valorized by the determination of biomass properties. The aim of this three years’ investigation was to analyze the biomass quality (proximate and ultimate analysis, calorific values, micro and macroelements) of Miscanthus x giganteus cultivated on soils with three cadmium (Cd) and mercury (Hg) contamination levels. All analyzed parameters, except Cd, K and Cr, are compatible with or have only expected differences from the literature data and/or ISO 17225–1:2014 norm for solid biofuels. The values of ash, volatile matter, C content and lower heating value as one of the most important energy parameters, are in the range 1.35–3.66%, 86.28–90.39%, 46.34–49.91% and 16.24–16.93 MJ/kg respectively.