Final Activity Report Summary - CONTROL-AD4H2 (Control of Anaerobic Digestion Processes for Optimisation of Hydrogen Production) Bio-hydrogen production from organic waste sources or energy crops represents an important area of energy production for global environmental considerations. Bio-hydrogen is indeed a clean and environmentally friendly fuel which produces water instead of greenhouse gasses when combusted. Furthermore, it has a high energy yield, which is about 2.7 times greater than that of hydrocarbon fuels and can be directly used to produce electricity in fuel cells with high efficiency. Hydrogen can be biologically produced from organic wastes using several methods among which anaerobic fermentation is a very attractive one. However, the main obstacles in bio-hydrogen application as an industrial process are the low yields and non-optimised processes. This project focussed on these points studying the following main objectives: 1. identification of important parameters influencing metabolic pathways for optimal hydrogen production; 2. comparison of the different modelling approaches available in literature for anaerobic digestion processes and inclusion of hydrogen pathways; 3. investigation of process configurations for maximising energy output of combined bio-hydrogen, as first priority, and biogas, as second priority, in a combined treatment process; 4. development of appropriate control laws to optimise hydrogen and biogas production. The main scientific achievements were: 1. a clear definition of the limiting factors to be addressed in complex but structured models like the Anaerobic digestion model (ADM1) of the International Water Association to take into account hydrogen production; 2. the development of a simpler model to represent some experimental data obtained at the host institute during the course of the project on hydrogen production; 3. the development of a model to represent pathogens reduction in sludge because of thermal treatment; 4. participation in the implementation of a closed loop control law that regulated the propionate concentrations in order to keep anaerobic digestion process stable and improve biogas production.