Lignin4BioGas: 3D-Printed Lignin Electrodes for Enhanced Biomethane Production in Microbial Electrolysis Cell-Integrated Anaerobic Digestion

Project Description

Ireland aims to reach net zero emissions by 2050, with the National Biomethane Strategy targeting 5.7 TWh of biomethane production by 2030. However, anaerobic digestion (AD), the primary biomethane production technique in Ireland, faces challenges such as low biomethane concentrations (50–70%), high CO₂ content (30–50%), slow organic matter degradation, and process instability due to accumulation of volatile fatty acids (VFAs). Lignin4BioGas addresses these issues by integrating Microbial Electrolysis Cells (MEC) with AD systems, using novel 3D-printed lignin-based carbon electrodes.

Lignin, a renewable by-product of Ireland’s agricultural and forestry sectors, will be used to fabricate electrodes with high surface area, porosity, conductivity, and tailored surface chemistry. These electrodes will be integrated into MEC-AD systems to enhance microbial colonisation, electron transfer, and organic breakdown, promoting electro-methanogenesis for CO₂ conversion into biomethane. The system performance will be tested with various agro-industrial wastes, and a Life Cycle Assessment (LCA) will quantify its environmental impact.

Lignin4BioGas potentially boosts biogas output by up to 50%, methane concentrations up to 85-88%, and reduces VFA accumulation by 30%, significantly improving system performance and stability. Additionally, 3D printing allows precise customisation of electrode geometry and configuration, reducing internal resistance and supporting scalability.

This will be the first project to apply lignin-based electrodes for biomethane production, positioning Ireland as a global leader in bioenergy innovation and waste stream valorisation. It aligns with SEAI Fellowship objectives by strengthening national sustainable energy capabilities and contributing to the 2030 biomethane target while supporting global climate action under SDGs 7 and 13.