Enriched biochar from forest industrial residues for fertilizing plants and woodland, NärSkog 2

Important results from the project

With the NärSkog 2 project, we wanted to find out if it is technically and economically possible to -reduce amounts of waste at Swedish pulp mills -reduce the use of mineral fertilizers at nurseries and forestry. -increase the amount of ash that is returned to the forest -contribute to increased sustainable resource utilization of skogsresursen By considering sludge and ash as resources and processing them into enriched hydrocoal that is then recirculated back to the forest, either together with plants or on a larger scale as a soil improver, all goals can be achieved.

Expected long term effects

Karlstad University has, in a successful collaborative project together with Stora Enso AB, Stora Enso Skog, Mellanskog, Econova, Karlstad municipality, the Swedish Forestry Agency, Paper province and Umeå University, developed and tested a new type of fertilizer for forest plants and forest land. We have evaluated various residual products from pulp mills with regard to nutrient content and heavy metals and found that it is possible to use sludge and ash for fertilizing forest plants but also on a larger scale for forestry. The sludge must first be processed into biochar or hydrochar.

Approach and implementation

Through the project, ideas have been tested practically. Cooperation with industrial actors led to large-scale experiments with industrial relevance. Two larger cultivation trials have been carried out at the nursery with approx. 10,000 plants in each round of trials. Some of these plants have then been planted out on selected clearings. Technology to pellet the material was developed into continuous production. The interdisciplinary composition of the project group has led to us all learning a lot from each other.