NOVELTY - Hydrogen is produced by introducing a feedstock comprising a biodegradable solid into a first stage anaerobic bioreactor and forming a liquid effluent, transferring the effluent into a second stage anaerobic bioreactor having hollow semipermeable fibers with an outer surface coated with a biofilm of hydrogenogenic bacteria, forming hydrogen within the lumen of the hollow semipermeable fibers, and removing the hydrogen from within the lumen.    USE - Used for producing hydrogen from manure of large animal production, food processing wastes, and energy crops such as grasses or corn. The hydrogen gas is used for energy production e.g. in fuel cell.    ADVANTAGE - The process provides beneficial disposition of high organic wastes generated by farms and industry.    DETAILED DESCRIPTION - Hydrogen production comprises introducing a feedstock comprising at least one biodegradable solid into a first stage anaerobic bioreactor and forming a liquid effluent; transferring the liquid effluent into a second stage anaerobic bioreactor having hollow semipermeable fibers having an outer surface coated with a biofilm comprising at least one hydrogenogenic bacteria, forming hydrogen within lumen of the hollow semipermeable fibers; and removing the hydrogen from within the lumen of the hollow semi-permeable fibers.    An INDEPENDENT CLAIM is also included for a system for producing hydrogen comprising a first stage anaerobic bioreactor vessel having a feedstock inlet and a liquid effluent outlet; a second stage anaerobic bioreactor vessel having a liquid effluent inlet in fluid communication with the liquid effluent outlet and a hydrogen gas outlet; and hollow semipermeable fibers disposed in the second stage anaerobic bioreactor vessel, hollow semipermeable fibers having an outer surface coated with a biofilm comprising hydrogenogenic bacteria.    DESCRIPTION OF DRAWING(S) - The drawing shows a diagram of the process design and the phenomenon in the second stage anaerobic bioreactor that generates the hydrogen.