Application of Doehlert design in optimizing the solid-state hydrogenogenic stage augmented with biomass fly ash in a two-stage biohythane production process.

This study aimed to optimize the solid-state hydrogenogenic stage supplemented with biomass fly ash in a two-stage anaerobic digestion (AD) process for biohythane production from the organic fraction of municipal solid waste (OFMSW). Doehlert's experimental design was used to obtain the optimal set of two investigated variables, namely total solids (TS) content and biomass fly ash dosage in the defined ranges of 0-20 g/L and 20-40%, respectively. Applying the optimal conditions of TS content (29.1%) and fly ash dosage (19.2 g/L) in the first stage led not only to a total H2 yield of 95 mL/gVSadded, which was very close to the maximum H2 yield predicted by the developed model (97 mL/gVSadded), but also to a high CH4 yield of 400 mL/gVSadded (76% of the theoretical CH4 yield). Moreover, the biohythane obtained from the optimized two-stage process met the standards of a biohythane fuel with an H2 content of 19% v/v.

Biohythane production via anaerobic digestion process: fundamentals, scale-up challenges, and techno-economic and environmental aspects.

Biohythane, a balanced mixture comprising bioH2 (biohydrogen) and bioCH4 (biomethane) produced through anaerobic digestion, is gaining recognition as a promising energy source for the future. This article provides a comprehensive overview of biohythane production, covering production mechanisms, microbial diversity, and process parameters. It also explores different feedstock options, bioreactor designs, and scalability challenges, along with techno-economic and environmental assessments. Additionally, the article discusses the integration of biohythane into waste management systems and examines future prospects for enhancing production efficiency and applicability. This review serves as a valuable resource for researchers, engineers, and policymakers interested in advancing biohythane production as a sustainable and renewable energy solution.