Workshops

E. Ficara (Politecnico di Milano), S. Weinrich (Münster University of Applied Sciences), G. Wells (Northwestern University), J.-P. Steyer (INRAE), A. Catenacci (Politecnico di Milano), T. Lippert (Northwestern University, Norwegian University for Science and Technology), D. Carecci​​ (Politecnico di Milano), H. Nielsen (Northwestern University), A. Meola (DBFZ), L. Raskin (Yale University), D. Batstone (The University of Queensland), J. Rodríguez (Khalifa University), R. Kleerebezem (Delft University of Technology), K. Gernaey (Technical University of Denmark)

Anaerobic digestion (AD) has evolved from sludge treatment to a versatile technology processing diverse organic waste streams, while its objectives now include both biomethane production and ensuring digestate quality as a key fertilizer product. Growing diversity in substrates and goals has driven new modeling efforts, integrating additional metabolic pathways and multi-criteria tools for system optimization. As AD applications expand—addressing climate impacts, resource recovery, and high-value bioproducts—future models must reflect this complexity. Building on the success of ADM1, this workshop will explore pathways toward harmonized modeling frameworks, model integration, and the potential development of a generalized ADM2 or interoperable model suite.

S. Hellmann (DBFZ), T. Lippert (Northwestern University, Norwegian University for Science and Technology), D. Carecci (Politecnico di Milano), H. Nielsen (​Northwestern University), G. Capson-Tojo (INRAE), J.-P. Steyer (INRAE), S. Weinrich (Münster University of Applied Sciences), L. Raskin (​Yale University), E. Ficara (Politecnico di Milano), G. Wells (​Northwestern University), D. Batstone (The University of Queensland), E. Fioribello (YWP) (INRAE), T. Segura (YWP) (INRAE), YWPs to be confirmed.

This second part of the workshop builds on the modeling concepts introduced in the morning session and focuses on making anaerobic digestion (AD) models operationally effective. As AD applications diversify, models must be both comprehensive and practically applicable at laboratory and full scale. Operational usefulness requires appropriate monitoring and automation, high-quality process data, and uncertainty-aware calibration of mechanistic and data-driven models. Addressing these interlinked elements is essential yet challenging due to hardware and data limitations. The workshop offers two parallel tracks: a hands-on introduction to AD modeling and a practice-oriented track on implementation, using real plant data and scenarios.

K. Koch (Technical University of Munich), S. Astals (University of Barcelona), S. Weinrich (Münster University of Applied Sciences), J. Carrillo-Reyes (Universidad Nacional Autónoma de México), S.D. Hafner (Aarhus University)

This workshop addresses the persistent variability in biochemical methane potential (BMP) measurements, which limits comparability and hinders effective anaerobic digestion (AD) research and implementation. Participants will gain the knowledge and practical competencies required to conduct accurate, reproducible BMP tests through theory, hands-on guidance, and critical data evaluation. The program covers core BMP principles, experimental design, high-quality data collection, data processing, and rigorous interpretation. Emphasis is placed on best practices consistent with the Standard BMP Methods (SBM) platform. Attendees will also be introduced to digital tools such as the Online Biogas App to support planning and data analysis.

Z. Cetecioglu (KTH Royal Institute of Technology), C. Chen (Beijing University of Chemical Technology), S. Greses (Universitat de València), A. Regueira (Universidade de Santiago de Compostela)

Anaerobic mixed cultures are highly sensitive to environmental conditions, making it difficult to predict the conversion and selectivity of carbon-rich substrates into specific carboxylates. This uncertainty remains a major barrier to advancing technologies based on the carboxylate platform. In contrast, anaerobic digestion has progressed significantly through the widespread use of the biomethane potential (BMP) test, a robust method for estimating methane yields. This workshop aims to consolidate ongoing initiatives toward developing an analogous carboxylate potential test, fostering discussion, coordination, and identification of concrete steps needed to advance its standardization, validation, and broader implementation.

Marina Arnaldos (Cetaqua), Celia M. Castro-Barros (Cetaqua), Javier Santos (Veolia), Mario Ruiz (Aigües de Barcelona), D. Parry (Jacobs), S. McClelland (Encina Wastewater Authority)

Water and wastewater utilities are undergoing a transition toward climate-neutral, circular resource platforms integrating energy production, water reuse, and nutrient recovery. Anaerobic digestion (AD) is central to this shift, transforming sewage sludge into renewable energy and recoverable resources, yet scaling advanced circular digestion models faces technical, regulatory, and social barriers. This workshop examines AD as a backbone technology for future utilities through flagship full-scale case studies in Spain and the USA, complemented by innovation perspectives and multi-stakeholder dialogue. Key questions address pathways for WWTPs to become circular, energy-positive systems and the most promising utility-scale innovations under current frameworks.

J. Lema (CRETUS), H. Carrere (INRAE), S.I. Pérez-Elvira (Institute of Sustainable Processes, University of Valladolid), D. Miguel (FACSA), D. Polanco (teCH4+), D. Parry (Jacobs), S. McClelland (Encina Wastewater Authority), D. Bolzonella (University of Verona), I. Pastor (FACSA), JB. Van Lier (Delft University of Technology)

This workshop addresses the persistent gap between research advances and full-scale implementation in sewage sludge anaerobic digestion (AD). It begins by outlining sector-wide barriers to technology transfer before focusing on pretreatment technologies, including thermal hydrolysis, supported by real success cases from full-scale WWTPs. The second part examines innovative AD configurations beyond conventional CSTRs, highlighting dual-temperature phased and cascade digestion systems that can enhance performance and reduce solids retention time. A final round table will gather researchers, technology providers, and operators to discuss operational lessons, remaining challenges, and priority innovation pathways, integrating fundamental research with full-scale experience.

S.K. Khanal (The Hong Kong University of Science & Technology), A.J.V. Cavaleiro (Universidade do Minho), L. Raskin (Yale University), P.H. Lee (Imperial College), L.T. Angenent (University of Tübingen), G.Y.A. Tan (City University of Hong Kong), M. Kreuk (Delft University of Technology), J.B. Lier (Delft University of Technology), R. Lindeboom (Delft University of Technology), B. Kraakman (Jacobs Engineering), K.C. Surendra (The Hong Kong University of Science & Technology), Z. Wu (Imperial College), M. Ho (Imperial College), T.Y.C. Lam (City University of Hong Kong), A. Pereira (Universidade do Minho), S. Duarte (Universidade do Minho), M. Zhou (The Hong Kong University of Science & Technology), K. Gemeinhardt (University of Tübingen), R. Karki (University of Michigan), S. Skerlos (University of Michigan), M. Picavet (Colsen)

Anaerobic digestion (AD) faces persistent challenges including process instability, slow hydrolysis, limited long-chain fatty acid degradation, reduced biogas quality, and hydrogen sulfide emissions. Micro-aeration—dosing small amounts of air or oxygen into the digester—has emerged as a promising strategy to overcome these bottlenecks. It enhances stability by reducing VFAs, accelerates hydrolysis, supports LCFA degradation, and effectively suppresses sulfide in both liquid and gas phases. Micro-aeration may also promote chain elongation and improve digestate dewaterability, enabling higher loading rates and methane yields. This workshop brings together leading researchers to explore the emerging field of micro-aerated AD and its technological potential.

J. L. Willis (Brown and Caldwell), Y. Bajón Fernández (Cranfield University), A. Al-Omari (Brown and Caldwell), R. Pfeufer (Eliquo Technologies), M. Haddad (Suez), C. Shekulski (USP/Trojan Technologies (Veralto)), E. Elbeshbishy (Toronto Metropolitan University), G. Nakhla (Western University), D. Batstone (University of Queensland), P. Berna (IWE Industrial Water Evaporator)

Anaerobic digestion (AD) is central to resource recovery and supports carbon-neutral, circular-economy objectives in WRRFs. However, post-digestion methane emissions, hydraulic constraints, and ammonia inhibition still limit climate-neutral and intensified operation. Emerging vacuum-based technologies—vacuum degassing, evaporation, and heat recovery—offer integrated, economically viable solutions. Operating under reduced pressure enables capture of dissolved methane and CO₂, nutrient recovery, and improved digestion performance. Vacuum degassing mitigates methane leakage, while vacuum-driven evaporation concentrates solids and removes ammonia, increasing digester capacity. This workshop presents advances in vacuum-enhanced AD, covering climate impacts, resource recovery, process intensification, modeling, and pathways toward policy and commercial adoption.

Cigdem Eskicioglu (Polytechnic University of Catalonia-BarcelonaTech), Isaac Owusu-Agyeman (KTH Royal Institute of Technology), Marina Arnaldos Orts (Cetaqua), Raquel Lebrero Fernandez (University of Valladolid), Raul Munoz Torre (University of Valladolid), Sergi Astals Garcia (University of Barcelona), Yadira Bajon Fernandez (Cranfield University), Graham Aid (RagnsSells)

Anaerobic bioprocesses are established for methane production and increasingly explored for generating value-added biochemicals, yet many waste streams remain underutilized. This workshop examines the potential of such streams within circular biorefinery concepts. Municipal wastewater and food waste hold significant recoverable resources, but large-scale implementation is limited by collection, separation, and anaerobic processing constraints. Source-separated fractions—such as blackwater or food waste—enable higher recovery efficiencies due to their concentrated carbon and nutrient content. Given the environmental burden and scale of global food waste, the workshop will explore anaerobic pathways and products that can unlock the untapped potential of these waste resources.

M. Elvira (Aqualia), C. Holohan (Radboud University), F. J. C. Magalhães (University of Rio Grande do Sul), M. A. Boncz (Federal University of Mato Grosso do Sul), J. Carrillo (University of Valencia), R. Muñoz (University of Valladolid), J. Kim (Inha University – TBC), L. Florencio (Federal University of Pernambuco – TBC)

Mainstream anaerobic wastewater treatment offers a pathway to efficient water resource recovery-oriented systems aligned with EU 2030 goals. Technologies such as UASB and AnMBR enable high-rate treatment, solids retention, energy recovery as biomethane, and production of high-quality effluents for reuse. However, large scale adoption remains constrained by challenges including cold climate performance, dissolved methane emissions, nutrient removal and recovery requirements, and operational limitations. This workshop will examine state of the art solutions, parallel processes for water and nutrient recovery, and biogas upgrading strategies. Key open questions include mitigating dissolved methane, ensuring effluent quality for reuse, and addressing nutrient management when fertigation is not feasible.