Microbial electrolysis is a novel bioelectrochemical process that is capable of producing hydrogen from dissolved organic materials in wastewaters. Microbial electrolysis achieves this by applying electrochemically active micro-organisms. These micro-organisms oxidize dissolved organic materials and subsequently release the produced electrons to an electrode surface. By electrochemically coupling this so-called biological anode to a hydrogen producing cathode by means of a power supply, electrolysis of the dissolved organic materials into carbon dioxide and hydrogen is accomplished. The theoretical energy requirement of microbial electrolysis is only about 0.26 kWh/Nm³ H₂, whereas that of commercial water electrolysis is typically over 5 kWh/Nm³ H₂.
The objective of this study was to assess the potential of this system for practical application and to provide an overview of the most important technical challenges that need to be dealt with in order to achieve practical application. Based on recent laboratory work, it is expected that the volumetric hydrogen production rates of microbial electrolysis can be improved to over 10 Nm³ H₂/m³ reactor volume/day. To get to a mature hydrogen production technology, however, it is important to realize a cost-effective scale-up that considers Ohmic losses and material costs. Although some researchers have aimed to develop scaleable designs for bioelectrochemical processes, no study has yet demonstrated that these technologies can indeed be operated properly beyond the litre-scale. The Advanced Water Management Centre of the University of Queensland is currently starting up a bioelectrochemical pilot plant at the Foster’s Brewery Yatala to investigate such scale-up issues.