Andreas Dyreborg Martin defends his PhD thesis
Andreas Dyreborg Martin defends his PhD thesis "Utilization of local biomass resources in integrated anaerobic digestionpyrolysis biorefineries in a circular bioeconomy context."
The defense is public, and everybody is welcome; the defense is scheduled for a maximum of three hours and will be held in English.
Follow the defense online via Zoom
The Doctoral School at Department of People and Technology will host a small reception afterwards from 16.00 - 17.30.
Supervisors and assessment
Assessment committee:
- Morten Ambye-Jensen, Associate Professor, Institut for Bio- og Kemiteknologi - Industrial Biotechnology, Aarhus University, Denmark
- J?rgen Held, M.Sc. i Mechanical Engnieering, Institute of Tecnology, Lund University, Sweden
- Thomas Budde Christensen, Professor, Department of People and Tecnology, 真人线上娱乐 University, Denmark (Chair)
PhD Supervisors:
- Tyge Kj?r, Associate Professor, Department of People and Technology, 真人线上娱乐 University, Denmark
- Tobias Pape Thomsen, Associate Professor, Department of People and Technology, 真人线上娱乐 University, Denmark
- Rikke Lyb?k, Associate Professor, Department of People and Technology, 真人线上娱乐 University, Denmark
Abstract
The thesis explores optimization local biomass resource utilization within a circular bioeconomy framework through integration of anaerobic digestion (AD) and pyrolysis technologies. The focus is on sustainability through innovative biorefinery systems that enhance nutrient recycling, carbon sequestration, and energy generation while to solve challenges regarding resource depletion and greenhouse gas emissions. This is mainly done through assessing potential synergies, bioresource mapping and municipal involvement.
The study is structured into two interconnected parts.
Part 1 focuses on mapping and assessing the availability, quality, and distribution of biomass resources across Danish and Swedish municipalities. The research utilizes GIS-based methodologies to evaluate the potential of second-generation biomass resources, including food waste, agricultural residues, and road verge grass. These resources are assessed for their spatial distribution, dry matter content, and nutrient composition. The results reveal notable geographical disparities in biomass availability, with areas facing critical deficits or surplus of essential nutrients like nitrogen and phosphorus. Some areas are more suited than others for integration of anaerobic digestion and pyrolysis, as low bioresource density and few available types of bioresource hinders flexibility which is required when establishing biorefineries. This uneven distribution underscores the need for localized strategies that prioritize the right nutrient recirculation and resource efficiency for the specific area.
Another component of this part is the co-development of a decision-support tool in collaboration with municipal stakeholders. This tool aims to bridge gaps in data accessibility and usability, enabling municipalities to assess biomass potential more effectively and design tailored strategies for sustainable resource utilization. Workshops conducted with municipal representatives highlight the importance of adapting technical data with local priorities and addressing challenges such as stakeholder collaboration and policy alignment.
Part 2 explores the integration of anaerobic digestion and pyrolysis technologies, evaluating their combined potential to enhance the efficiency and sustainability of biorefinery systems. The research explores two primary synergies:
- The use of biochar, a co-product of pyrolysis, as an amendment in anaerobic digestion to optimizemethane production.
- The application of biochar for hydrogen sulfide removal from biogas.
Biochar amended digestate can optimize anaerobic digestion but can also have the opposite effect. Additionally, biochar proves to be an effective adsorbent for hydrogen sulfide in gas, offering a low-cost solution for biogas purification but some biochar performs very poorly. Therefore, effective utilization of biochar differs depending on the application it is used in and it is suggested to use biochar for multiple purposes by operating anaerobic digestion and pyrolysis systems in parallel, allowing each technology to capitalize on its strengths while contributing to a cascading system of resource utilization.
The cascading use of biochar is highlighted as a promising approach to maximize its value. Initially, biochar is employed to optimize anaerobic digestion and biogas purification processes. Subsequently, it is applied as a soil amendment, where its long-term benefits can include carbon sequestration, improved soil fertility, and enhanced water retention. These cascading applications illustrate the potential of biochar to serve as a multifunctional tool in circular bioeconomy systems.
This research contributes to the growing field of circular bioeconomy by providing actionable insights into the codevelopment and integration of anaerobic digestion and pyrolysis technologies. It demonstrates that these technologies, when strategically aligned with local resource dynamics and supported by robust stakeholder collaboration, can transform biomass into high-value products while addressing critical sustainability challenges. The findings have significant implications for policymakers, researchers, and practitioners, offering a scalable framework for implementing circular bioeconomy practices at the municipal level and beyond.
In conclusion, this thesis provides a comprehensive framework for enhancing the utilization of biomass resources through the synergistic integration of anaerobic digestion and pyrolysis. By addressing technical, environmental, and social dimensions, it lays the groundwork for advancing sustainable transitions in Denmark, Sweden, and possible similar regions worldwide.
The dissertation will be available for reading at the 真人线上娱乐 University Library before the defense (on-site use). The dissertation will also be available at the defense.