In 2019, we ran a pilot to turn a problematic side stream, green liquor dregs, into crushed geopolymers. The solution turned out to be a resource efficient way to replace natural stone in infra construction.
Last year together with a Finnish forestry company, Betolar piloted how green liquor dregs (GLD) could be utilized as an infra construction material. Using Betolar’s recipe and methodology, GLD was turned into crushed geopolymers and used in the sub-base of field structure, substituting stone material.
For forestry companies, GLD is one of the most challenging side streams to recycle. It is produced during pulp manufacturing and amounts to over one million tons per year. Though the forest industry has actively been innovating ways to recycle it, there has not yet been found any large-scale applications. Thus, most of the global GLD is currently landfilled. (Kinnarinen et al. 2016)
After the pilot, Betolar had a natural resource report conducted by a third party. Compared to conventional crushed natural stone, Betolar’s piloted solution saves natural resources up to 95%.
The lysimeter tests also showed that the heavy metal leaching of the end product is clearly below the Finnish standards, Government Decree on the Recovery of Certain Wastes in Earth Construction (843/2017).
The pilot demonstrates that Betolar’s solution to turn GLD to crushed geopolymers is well suitable to be used in the sub-base of field and road structures. The crush is especially suitable and sustainable when the location of the end product is close to the production site of the GLD.