Innovative use of bio-ashes from wood combustion for a more profitable and sustainable forestry management

The Ash Value project aims at converting waste bio-ashes into resources for more profitable and sustainable forestry and agriculture management. The project aims at developing a new ash-based soil improvement product. Further, a competence platform for establishing a national regulation on recycling wood ashes back to the forests should be established. Today there are no Norwegian national regulations for recycling of ash to the forest. Such regulations are needed to maintain productive forests, by  preventing soil acidification due to acidification from natural tree growing and acid rain deposits. In addition, there is a need for compensating for the slow depletion of nutrients that will occur as a result of increased harvesting of forest residues for bioenergy purposes.

In the Ash Value project, PFI is responsible for the work package on ash pretreatment or ash hardening. Here, PFI is exploring how various types of bioashes should be granulated (pelletised etc) and hardened in order to produce a hardened ash granulate suitable for handling and storage with desired leaching characteristics of alkaline salts. Hardening mechanisms are explored and both bottom ashes and fly ashes are tested either separately or in combination with nitrogen-containing organic waste fractions.