Abstract
Bread waste is a major contributor to food waste in the UK, creating significant environmental and resource management challenges. This study develops an integrated bread waste biorefinery framework to support circular bioeconomy objectives by simultaneously addressing environmental, economic, and social performance. A multi-objective optimisation model, formulated as a mixed-integer nonlinear programming problem and solved using an augmented ε-constraint approach, was applied to optimise net present value (NPV), global warming potential (GWP) savings, and employment generation. The framework integrates anaerobic digestion and incineration with biorefinery pathways under three heat supply strategies: fully internal, partially external, and fully external heat provision. Results reveal clear trade-offs between objectives. Fully internal heat supply maximises environmental performance, achieving up to 361,741 tCO₂-eq yr⁻¹ GWP savings, while external heat supply delivers superior economic and social outcomes, with NPV up to 733 M$ and 4881 jobs. The proposed framework provides robust decision support for sustainable food-waste management.