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ARS Home » Plains Area » Las Cruces, New Mexico » Cotton Ginning Research » Research » Publications at this Location » Publication #409638
Research Project: Improving the Production and Processing of Western and Long-Staple Cotton and Companion Crops to Enhance Quality, Value, and Sustainability

Location: Cotton Ginning Research

Title: Forest industrial waste materials upgraded to fertilizer pellets for forest soil

Author
item SANDBERG, MARIA - Karlstad University
item FRODESON, STEFAN - Karlstad University
item BRUNZELL, LENA - Karlstad University
item Tumuluru, Jaya Shankar

Submitted to: Sustainability
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/20/2024
Publication Date: 3/29/2024
Citation: Sandberg, M., Frodeson, S., Brunzell, L., Tumuluru, J. 2024. Forest industrial waste materials upgraded to fertilizer pellets for forest soil. Sustainability. 16(7). https://doi.org/10.3390/su16072868.
DOI: https://doi.org/10.3390/su16072868

Interpretive Summary: The focus of the study is to utilize residual products from the forest industry and upgrade these to a biochar-based nutrient pellet for adding back nutrients to forests. The pulp and paper production sludge, bark and ash, blend was hydrothermal carbonized and pelletize at different ratios and studied for their performance in forests. The blend pellets produced met the ISO standards in terms of pellet quality attributes of bulk density and durability. The nutrient leaching studies conducted on the pellets indicated that heavy metals leach slowly compared to micronutrients. Adding back the nutrients to forests can have great impact on improving the forest soils fertility and support the circular bioeconomy.

Technical Abstract: In a circular economy, the efficient utilization of all materials as valuable resources, with a focus on minimizing waste, is paramount. This study shows the possibilities of upgrading the lowest-valued residuals from the forest industry into a new product with both liming and fertilizing properties on forest soil. Hydrothermal carbonized sludge mixed with bark and ash in the proportions of 45:10:45 was densified into fertilizer pellets that meet the nutrient requirements of 120 kg N per hectare when 7 tons of pellets is spread in forests. The pellets met a high-quality result according to durability and density, which were above 95% and 900 kg/m3. However, pellets exposed to wet and cold conditions lost their hardness, making the pellets dissolve over time. Small amounts, <5‰, of nutrients, alkali ions, and heavy metals leached out from the pellets under all conditions, indicating good properties for forest soil amendment. The conclusion is that it is possible to close the circle of nutrients by using innovative thinking around forest industrial residual products.