Biohydrogen Production from Biowaste: HAZOP Analysis Applied to a Pilot-Scale Reactor

This paper focuses on the HAZOP (Hazard and Operability) analysis applied to a dark fermentation process designed to produce biohydrogen. A pilot reactor for hydrogen production from sludge and the organic fraction of municipal solid waste was studied. With reference to the fermenter (the key process node), operating conditions both maximizing process efficiency and representing the worst-case scenario in terms of process safety have been chosen. The HAZOP analysis enabled the identification of deviations from normal operating conditions, looking for causes, consequences, and countermeasures, including the effects of microbial community variations on process efficiency. The analysis highlighted significant engineering solutions (gas detectors, temperature and flow transmitters, Distributed Control System, etc.) aimed at increasing process efficiency while simultaneously enhancing safety levels for operators and the environment. Finally, the results of the pilot reactor analysis can be applied to the development of full-scale plants.