The deliverable D6.3 addresses a thorough evaluation of the physico-chemical and phytotoxic properties of the different type of biomass ashes produced during the FPBO production process. This includes the reference biomass ashes obtained from clean pinewood ‘crumbles’, as well as those derived from four different waste streams (forest residues, wheat straw, bark and Miscanthus sp.). The final aim by doing so is to assess the potential applicability of the characterised ashes as soil amendments in agriculture and forestry. Overall, the physico-chemical properties from the aforementioned ashes seem to be similar to those from other type of ashes reported in the literature. They showed a high nutrient status and an alkaline pH (around 12), which indicates that they can be used as a replacement for lime so as to reduce soil acidity. Their potential inhibitory effect on plant growth also disappeared after being diluted; and, in addition, very low (or negligible) polycyclic aromatic hydrocarbon levels were found in the ashes, suggesting a good combustion process regardless of the initial feedstock used for the fast pyrolysis. The only concern is their level on heavy metals specially Cr, that could limit their use as soil amendments in the long-term.
|D6.3 Ash characterization|