Does inoculum really affect bio-hydrogen production from OFMSW?.

Biological production of hydrogen (H2) is an exciting scientific area for the production of bioenergy from low-cost residues and wastes. Hydrogen production by fermentative bacteria, not light dependent, is known as “dark fermentation” and takes place during the fermentation phase of the anaerobic digestion. Anaerobic sludges collected from full scale digesters are frequently reported in scientific literature to be used as inoculum for hydrogen production. The main requirement for an efficient H2 production process is linked to the availability of efficient mixed microbial consortia in which H2-utilizing and non-H2-producing bacteria are suppressed. This study was performed to evaluate the H2 production potentials of the organic fraction of municipal solid waste (OFMSW) without inoculum addition. The H2 production levels were compared to those achieved from the OFMSW seeded with 4 hours heattreated granular sludge. Hydrogen production performances were also assessed using mathematical models. Results suggest that hydrogen production from OFMSW is feasible without inoculum since the indigenous bacteria naturally occurring on the substrate resulted able, after a 5-6 days latency phase, to produce H2 at levels comparable to those achieved in the presence of the pre-treated inoculum. However, the addition of a properly pre-treated inoculum confirmed to be an interesting and improvable tool to obtain high H2 yields from organic wastes.