Biohythane (methane and hydrogen) regeneration from agricultural biomass residue: Possible or utopia?

This mini review is mainly on the initial discussion to the point-of-view of the conceptual bioenergy factors of anaerobic digestion towards biohythane (hydrogen and methane) production. Currently, the recent attention from the highly organic wastewater discharge as a major contribution to biohythane production rate. Then, few reviews on the strategies which had been applied to improve the biohythane production from the existing anaerobic digestion are revealed from the collective literature. A lot of efforts have been made to emphasize on the co-digestion and biomass retention improvement within the digester, but has a limited discussion on the utilization of solid biomass (especially agricultural residue) as the main substrate. Other studied strategies to the realization of biohythane from agro-biomass include the selective pre-treatment, additives supplementation (co-digestion and co-mixing of the substrate), bioreactor modifications and engineering influential factors for the controlled process. By integrating the suitable pre-treatment facility and operating the two-stage of anaerobic digestion technology, these applied strategies had become a positive and successive response to the biohythane production.