Valorization of agricultural and industrial side streams: energy potential and environmental assessment

Abstract

The growing global demand for food, energy, chemicals, and materials has intensified the pressure on natural resources. In this context, biomass residues emerge as a promising alternative for producing energy and bio-based products. To that end, it is essential to prioritize the use of domestic, agricultural, and industrial waste streams, thereby mitigating concerns commonly associated with conventional bioenergy production, such as deforestation, biodiversity loss, and food security risks. A shift in perspective is required: biomass residues should no longer be viewed merely as waste, but as valuable feedstocks that can be reintegrated into industrial and agricultural cycles.

The effective valorization of biomass residues is complicated due to their heterogeneous nature. The wide variety of feedstock types and their differing physicochemical properties demand careful characterization and process-specific evaluation. The performance of any conversion method is heavily influenced by feedstock composition, moisture, ash content, and other factors that affect energy yields, process stability, and product quality. Untreated biomass often presents limitations for large-scale applications, requiring tailored pre-treatment or conversion strategies. To address these challenges, the present dissertation employed a multidisciplinary approach that integrates analytical characterization, experimental studies, simulation, and environmental assessment to evaluate the potential and implications of valorizing various biomass residues.

This research contributes to the broader understanding of biomass resource recovery by focusing on both agricultural and industrial contexts. It investigates the valorization of several underutilized biomass streams through advanced conversion technologies, with a particular emphasis on hydrothermal treatments. The agricultural residues studied include those from major Colombian agro-industrial crops, while the industrial side-streams focus on kraft lignin and pulp mill biosludge from the Nordic pulp and paper industry. Across these cases, the study demonstrates that such residues can be transformed into energy carriers or value-added bioproducts, supporting the transition toward sustainable energy systems and circular economy models.