Evaluation of the utilization potential of debarking residue based on the requirements of Finnish waste legislation

The utilization aspects of debarking residue originating from the debarking of roundwood at an integrated pulp and board mill complex were investigated from the point of view of utilization under Finnish legislation. In Finland, the landfill deposition of organic material was restricted in 2016. The very high total organic carbon value of 385 g kg⁻¹ (d.w.) and the loss on ignition value of 91.0% (d.w.) of the studied debarking residue both exceeded the limit value of 10% for organic materials allowed to landfill at a conventional landfill in Finland. Therefore, this residue is not allowed to be sent for landfill disposal. Due to the low dry matter content of 27.5%, this residue is also uneconomic to incinerate. Therefore, other options than incineration or landfilling must be found for its management. Due to the low total heavy metal concentrations, which were lower than their current Finnish limit values for ash used as a forest fertilizer, this material is a potential industrial residue to be used, e.g. as a fertilizer or a soil amelioration agent. According to the sequential extraction procedure, heavy metals are tightly bound to the sample matrix and this supports the possible utilization of this residue. The total heavy metal concentrations in the debarking residue were lower than the current Finnish limit value for maximum allowable heavy metal concentrations for materials used as an earth construction agent. Therefore, this residue is also suitable for use for various landscaping purposes.